spring-boot-jap-layui-mysql 完整的jpa多对一

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.xfyuao</groupId>
    <artifactId>spring-boot-jpa-layui-2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-jpa-layui-2</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.2.6.RELEASE</spring-boot.version>
    </properties>

    <dependencies>
        <!-- jpa依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <!-- springmvc依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- mysql依赖 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <!-- 热部署 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
            <scope>true</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <!-- springboot版本 -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

#应用项目名称
#server.context-path=/mydemo
#应用端口
#server.port=8080

# 数据源配置，IDEA当中需主动配置时区为GMT+8
spring.datasource.url=jdbc:mysql://localhost:3306/ace?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=admin
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

##Spring Data JPA 配置，指明用的数据库，数据库方言，因为要生成sql语句
spring.jpa.database-platform=org.hibernate.dialect.MySQL5Dialect
##运行时输出 jpa 执行的 sql 语句
spring.jpa.show-sql=true
## spring-boot-starter-data-jpa 自动映射创建表动作 配置: 有表更新,无表创建，按名称判断不会更新类型
spring.jpa.hibernate.ddl-auto=update

#修改 tomcat 的 URIEncoding 为 UTF-8
server.tomcat.uri-encoding=UTF-8
#集中解决各种编码问题
#banner.charset=UTF-8
spring.http.encoding.charset=UTF-8
spring.http.encoding.enabled=true
spring.http.encoding.force=true
spring.messages.encoding=UTF-8

#jackson 对日期时间格式化设置
#springmvc(也就是controller层)返回前端页面时遵守的日期格式，把Date转化为String
spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
#jackson 对日期时间格式化设置:时区设置
spring.jackson.time-zone=GMT+8

package com.xfyuao;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication
@EnableJpaRepositories("com.xfyuao.dao")
public class App {

    public static void main(String[] args) {
        SpringApplication.run(App.class,args);
    }
}

package com.xfyuao.domain;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import javax.persistence.*;
import java.io.Serializable;
@Entity//基于该类建表
@Table(name = "t_dept")//表名
@Data//主要要getter、setter、toString
@AllArgsConstructor//全参构造器
@NoArgsConstructor//无参构造器
public class Dept implements Serializable {
    @Id//标注主键列
    @GeneratedValue(strategy = GenerationType.IDENTITY)//mysql支持主键自增
    @Column(columnDefinition="int unsigned NOT NULL comment ‘备注:部门编号，主键自动增长‘")
    private Integer deptNo;
    @Column(columnDefinition="varchar(20) NOT NULL comment ‘备注:部门名称‘")
    private String dname;
    @Column(columnDefinition="text comment ‘备注:办公地点‘")
    private String loc;
}

package com.xfyuao.domain;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import javax.persistence.*;
import org.springframework.format.annotation.DateTimeFormat;
import java.io.Serializable;
import java.util.Date;

@Entity
@Table(name = "t_emp")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Emp implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(columnDefinition = "int unsigned NOT NULL comment ‘备注:员工编号，主键自动增长‘")
    private Integer empNo;
    @Column(columnDefinition = "char(34) NOT NULL comment ‘备注:后台生成的卡号‘")
    private String empCardNo;
    @Column(columnDefinition = "varchar(20) NOT NULL comment ‘备注:员工姓名‘")
    private String ename;
    @Column(columnDefinition = "datetime NOT NULL comment ‘备注:入职日期‘")
    @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")//springmvc接收日期字符串时按该格式转化成日期
    private Date hiredate;
    @Column(columnDefinition = "char(1) NOT NULL comment ‘备注:员工状态，0表示正常在职‘")
    private Integer state;
    @Column(columnDefinition = "text comment ‘备注:备注‘")
    private String remake;
    // 不要级联增删改
    @ManyToOne(targetEntity = Dept.class, cascade = CascadeType.REFRESH, fetch = FetchType.EAGER)
    //会自动在emp表新建非空列dept_no，作为外键，但不会创建外键约束
    @JoinColumn(name = "deptNo", referencedColumnName = "deptNo")
    private Dept dept;

}

package com.xfyuao.dao;

import com.xfyuao.domain.Dept;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;
import javax.transaction.Transactional;

/**
 * 部门的dao接口，一个方法对于一条sql语句
 * 继承JpaRepository接口获取基本的crud方法
 * 继承JpaSpecificationExecutor获取实现动态sql查询的方法
 * */
public interface DeptDao extends JpaRepository<Dept, Integer>, JpaSpecificationExecutor<Dept> {
   
    /**
     * 这个方法完全不用写，就使用save方法返回实体类即可
     * 原因：继承的修改方法，在修改时如果没有某一列的值会把该列修改为null，
     * 所以想修改部分列、但不修改的列未传值，就需要使用自定义修改语句：JPQL或原生SQL
     * 方式：原生SQL
     * @return Modifying queries can only use void or int/Integer as return type!
     * */
    @Query(value = "update t_dept set dname=?1,loc=?2  where dept_no=?3 ", nativeQuery = true)
    @Modifying
    @Transactional
    public Integer updateDept(String dame,String loc,Integer deptNo);
    
}

package com.xfyuao.dao;

import com.xfyuao.domain.Dept;
import com.xfyuao.domain.Emp;
import java.util.List;
import javax.transaction.Transactional;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;

public interface EmpDao extends JpaRepository<Emp, Integer>, JpaSpecificationExecutor<Emp> {
    /**
     * 根据外键id查询，使用的是关键字抽象方法，也可以使用原生sql实现；
     * @param dept 只需要部门编号即可
     * @return 该部门下的学生
     * */
    /*关键字抽象方法：findBy/readBy/getBy开头，加上属性名，
     * 表示根据该属性查询，参数对应该属性，有多个条件使用关键字拼接
     */
    public List<Emp> findByDept(Dept dept);
}

package com.xfyuao.dto;

import java.util.Date;
import org.springframework.format.annotation.DateTimeFormat;
import com.xfyuao.domain.Emp;
import lombok.Data;

/**
 * 数据传输类，有额外的查询条件在该类中定义
 * 如：日期区间的多的一个日期
 * */
@Data
public class EmpDto extends Emp {
    @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
    private Date hiredate2;//结束日期
    
    //page分页的一种实现方式，另一种是每次接数据直接用PageUtil类接，参见DeptController的selectPageDept方法
    private Integer page=1 ;// 页码
    private Integer limit=10;// 每页条数
    
    @Override
    public String toString() {
        return super.toString() + " EmpDto [hiredate2=" + hiredate2 + ", page=" + page + ", limit=" + limit + "]";
    }
    
}

package com.xfyuao.service;

import com.xfyuao.domain.Dept;
import com.xfyuao.util.PageUtil;
import java.util.List;
import org.springframework.data.domain.Page;

/**
 * 部门的业务层，一个方法对应页面一个按钮功能
 * 复杂业务逻辑要在本接口的实现类实现
 * */
public interface DeptService {

    /**
     * 新增部门
     * 
     * @param dept 页面传递的要新增的部门信息
     * @return 返回带id的部门对象
     */
    public Dept insert(Dept dept);

    /**
     * 删除部门
     * 
     * @param deptNo 要删除的部门的编号
     * @return 返回状态码，1表示成功
     */
    public Integer delete(Integer deptNo);

    /**
     * 修改部门
     * 
     * @param dept 页面传递的要修改的部门信息
     * @return 返回修改后的部门对象
     */
    public Integer update(Dept dept);

    /**
     * 动态条件分页查
     * 
     * @param deptDto 查询条件，包含分页
     * @return 查询到的Page对象
     */
    public Page<Dept> selectByDynamicSQLPage(Dept dept, PageUtil pageUtil);

    /**
     * 查所有
     * 员工的条件查、新增和修改员工、不能重复添加，都需要查所有
     * @return 查询到的部门结果集
     */
    public List<Dept> selectAll();
}

package com.xfyuao.service;

import com.xfyuao.domain.Emp;
import com.xfyuao.domain.Emp;
import com.xfyuao.dto.EmpDto;
import com.xfyuao.dto.EmpDto;
import java.util.List;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;

public interface EmpService {
    /**
     * 新增员工
     * 
     * @param emp 页面传递的要新增的员工信息
     * @return 返回带id的员工对象
     */
    public Emp insert(Emp emp);

    /**
     * 删除员工
     * 
     * @param empNo 要删除的员工的id
     * @return 返回状态码
     */
    public Integer delete(Integer empNo);

    /**
     * 修改员工
     * 
     * @param emp 页面传递的要修改的员工信息
     * @return 返回修改后的员工对象
     */
    public Emp update(Emp emp);

    /**
     * 动态条件分页查
     * 
     * @param empDto 查询条件，包含分页
     * @return 查询到的Page对象
     */
    public Page<Emp> selectByDynamicSQLPage(EmpDto empDto);

    /**
     * 根据外键查询
     * 
     * @param deptNo 要查询的部门
     * @return 该部门下的员工
     */
    public List<Emp> selectByDeptNo(Integer deptNo);

}

package com.xfyuao.service.impl;

import java.util.List;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Expression;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;

import com.xfyuao.dao.DeptDao;
import com.xfyuao.domain.Dept;
import com.xfyuao.service.DeptService;
import com.xfyuao.util.PageUtil;

@Service // spring的ioc的体现，当前类交给spring管理（创建对象）并标注为service层
public class DeptServiceImpl implements DeptService {

    @Autowired
    private DeptDao deptDao;

    @Override
    public Dept insert(Dept dept) {
        return deptDao.save(dept);
    }

    @Override
    public Integer delete(Integer deptNo) {
        try {
            deptDao.deleteById(deptNo);
            return 1;// 不报错就返回1，模仿数据库成功则受影响的行是1
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("删除失败！");
        }
        return 0;
    }

    @Override
    public Integer update(Dept dept) {
        return deptDao.updateDept(dept.getDname(), dept.getLoc(), dept.getDeptNo());
    }

    @Override
    public Page<Dept> selectByDynamicSQLPage(Dept dept, PageUtil pageUtil) {
        // 根据主键倒叙
        Sort sort = Sort.by(Sort.Direction.DESC, "deptNo");
        // 传入分页条件：页码和条数
        Pageable pageable = PageRequest.of(pageUtil.getPage() - 1, pageUtil.getLimit(), sort);
        // 动态SQL语句
        Specification<Dept> spec = this.myWhere(dept);
        return deptDao.findAll(spec, pageable);
    }

    @Override
    public List<Dept> selectAll() {
        return deptDao.findAll();
    }

    private Specification<Dept> myWhere(Dept dept) {
        Specification<Dept> spec = new Specification<Dept>() {

            @Override
            public Predicate toPredicate(Root<Dept> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                Predicate predicate = cb.conjunction();// 动态 SQL 表达式
                List<Expression<Boolean>> exList = predicate.getExpressions();
                // 如果传来的条件中包含dname，就对dname模糊查
                if (dept.getDname() != null && !"".equals(dept.getDname())) {
                    exList.add(cb.like(root.<String>get("deptName"), "%" + dept.getDname() + "%"));
                }
                return predicate;
            }
        };
        return spec;
    }

}

package com.xfyuao.service.impl;

import java.util.Date;
import java.util.List;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Expression;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;

import com.xfyuao.dao.EmpDao;
import com.xfyuao.domain.Dept;
import com.xfyuao.domain.Emp;
import com.xfyuao.dto.EmpDto;
import com.xfyuao.service.EmpService;

@Service
public class EmpServiceImpl implements EmpService {

    @Autowired
    private EmpDao empDao;

    @Override
    public Emp insert(Emp emp) {
        return empDao.save(emp);
    }

    @Override
    public Integer delete(Integer empNo) {
        try {
            empDao.deleteById(empNo);
            return 1;
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("删除失败！");
        }
        return 0;
    }

    @Override
    public Emp update(Emp emp) {
        return empDao.save(emp);
    }

    @Override
    public Page<Emp> selectByDynamicSQLPage(EmpDto empDto) {
        Sort sort = Sort.by(Sort.Direction.ASC, "empNo");
        Pageable pageable = PageRequest.of(empDto.getPage() - 1, empDto.getLimit(), sort);
        Specification<Emp> spec = this.myWhere(empDto);
        return empDao.findAll(spec, pageable);
    }

    private Specification<Emp> myWhere(EmpDto empDto) {
        Specification<Emp> spec = new Specification<Emp>() {

            @Override
            public Predicate toPredicate(Root<Emp> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                Predicate predicate = cb.conjunction();// 动态 SQL 表达式
                List<Expression<Boolean>> exList = predicate.getExpressions();

                if (empDto.getEname() != null && !"".equals(empDto.getEname())) {
                    exList.add(cb.like(root.<String>get("ename"), "%" + empDto.getEname() + "%"));
                }
                if (empDto.getEmpCardNo() != null && !"".equals(empDto.getEmpCardNo())) {
                    exList.add(cb.like(root.<String>get("empCardNo"), "%" + empDto.getEmpCardNo() + "%"));
                }
                //大于开始日期
                if (empDto.getHiredate() != null) {
                    exList.add(cb.greaterThanOrEqualTo(root.<Date>get("hiredate"), empDto.getHiredate()));
                }
                //小于结束日期
                if (empDto.getHiredate2() != null) {
                    exList.add(cb.lessThanOrEqualTo(root.<Date>get("hiredate"), empDto.getHiredate2()));
                }
                // 根据外键列查询
                if (empDto.getDept() != null && empDto.getDept().getDeptNo() != null) {
                    // 等值使用equal(x,y)
                    exList.add(cb.equal(root.<Integer>get("dept"), empDto.getDept().getDeptNo()));
                }
                return predicate;
            }
        };
        return spec;
    }

    @Override
    public List<Emp> selectByDeptNo(Integer deptNo) {
        return empDao.findByDept(new Dept(deptNo, null, null));
    }

}

package com.xfyuao.web;

import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.xfyuao.domain.Dept;
import com.xfyuao.domain.Emp;
import com.xfyuao.service.DeptService;
import com.xfyuao.service.EmpService;
import com.xfyuao.util.PageUtil;
import com.xfyuao.util.Result;

/**
 * 控制层
 */
@RestController // 每个方法都返回json数据，不走视图解析器
public class DeptController {

    @Autowired // spring的DI，依赖注入，这个是自动注入，自动去spring容器找同名或同类型的对象给该属性赋值
    private DeptService deptService;
    @Autowired
    private EmpService empService;

    /**
     * http://localhost:8080/insertDept 新增，id自增
     * 
     * @param dep
     * @return 0代表成功
     */
    @RequestMapping("/insertDept")
    public Object insertDept(Dept dept) {
        // 简单的业务逻辑可以放在controller层实现
        /* 新增前先判断是否已存在
         * 1.查询所有记录，然后判断名称是否存在，
         * 2.数据行和列较少，考虑没必要单独查名称
         * 3.员工模块的条件查也会用到全查所有部门
         * */
        List<Dept> list = deptService.selectAll();
        for (Dept d : list) {
            if (d.getDname().equals(dept.getDname())) {
                return new Result(1, "添加失败，该名称已存在！");
            }
        }
        Dept de = deptService.insert(dept);
        if (de != null) {
            return new Result(0, "添加成功！");
        }
        return new Result(2, "添加失败！");
    }

    /**
     * http://localhost:8080/deleteDept 根据id删除
     * 
     * @param depId
     * @return 0代表成功
     */
    @RequestMapping("/deleteDept")
    public Object deleteDept(Integer deptNo) {
        // 删除前先判断该部门下是否有数据（员工）
        List<Emp> list = empService.selectByDeptNo(deptNo);
        if (!list.isEmpty()) {
            return new Result(1, "该部门下有数据，删除失败！");
        }
        Integer i = deptService.delete(deptNo);
        if (i == 1) {
            return new Result(0, "删除成功！");
        }
        return new Result(1, "删除失败！");
    }

    /**
     * http://localhost:8080/updateDept 修改
     * 
     * @param dept
     * @return 0代表成功
     */
    @RequestMapping("/updateDept")
    public Object updateDept(Dept dept) {
        List<Dept> list = deptService.selectAll();
        for (Dept d : list) {
            // if (d.getDname().equals(dept.getDname())) {
            // 如果只判断名字，没修改直接提交时会报错，因为原名字是存在的
            // 所以还要判断id，如果传入的名字、id和某一条数据的完全一样，表示是同一条
            if (d.getDname().equals(dept.getDname()) && !d.getDeptNo().equals(dept.getDeptNo())) {
                return new Result(1, "修改失败，该名称已存在！");
            }
        }
        Integer i = deptService.update(dept);
        if (i == 1) {
            return new Result(0, "修改成功！");
        }
        return new Result(1, "修改失败！");
    }

    /**
     * http://localhost:8080/selectPageDept 动态条件分页查
     * 
     * @param dept 查询条件 pageUtil 分页数据
     * @return layui数据表格要的数据格式
     */
    @RequestMapping("/selectPageDept")
    public Object selectPageDept(Dept dept, PageUtil pageUtil) {
        Page<Dept> page = deptService.selectByDynamicSQLPage(dept, pageUtil);
        /*layui要的正确数据：            该页数据                总条数
         *     成功时：{"code":0, "msg":"", data:[{},{}...], count:100}
         *     code不为0则为失败，需要在msg中放入失败原因
         */
        return new Result(0, "", page.getContent(), page.getTotalElements());
    }

    /**
     * http://localhost:8080/selectAllDept 查全部
     * 
     * @return 全部部门
     */
    @RequestMapping("/selectAllDept")
    public Object selectAllDept() {
        return deptService.selectAll();
    }
}

package com.xfyuao.web;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.xfyuao.domain.Emp;
import com.xfyuao.dto.EmpDto;
import com.xfyuao.service.EmpService;
import com.xfyuao.util.CardUtil;
import com.xfyuao.util.Result;

@RestController
public class EmpController {

    @Autowired
    private EmpService empService;

    /**
     * http://localhost:8080/insertEmp 新增，id自增
     * 
     * @param emp
     * @return 0代表成功
     */
    @RequestMapping("/insertEmp")
    public Object insertEmp(Emp emp) {
        System.out.println("接收到的要新增的emp:"+emp);
        //调用工具类获取一个员工卡号
        emp.setEmpCardNo(CardUtil.getEmpCard());
        Emp e = empService.insert(emp);
        if (e != null) {
            return new Result(0, "添加成功！");
        }
        return new Result(2, "添加失败！");
    }

    /**
     * http://localhost:8080/deleteEmp 根据id删除
     * 
     * @param empNo
     * @return 0代表成功
     */
    @RequestMapping("/deleteEmp")
    public Object deleteEmp(Integer empNo) {
        Integer i = empService.delete(empNo);
        if (i == 1) {
            return new Result(0, "删除成功！");
        }
        return new Result(1, "删除失败！");
    }

    /**
     * http://localhost:8080/updateEmp 修改
     * 
     * @param emp
     * @return 0代表成功
     */
    @RequestMapping("/updateEmp")
    public Object updateEmp(Emp emp) {
        Emp e = empService.update(emp);
        if (e != null) {
            return new Result(0, "修改成功！");
        }
        return new Result(1, "修改失败！");
    }

    /**
     * http://localhost:8080/selectPageEmp 动态条件分页查
     * 
     * @param empDto 查询条件
     * @return layui数据表格要的数据格式
     */
    @RequestMapping("/selectPageEmp")
    public Object selectPageEmp(EmpDto empDto) {
        System.out.println("emp查询条件："+empDto);
        Page<Emp> page = empService.selectByDynamicSQLPage(empDto);
        return new Result(0, "查询成功", page.getContent(), page.getTotalElements());
    }
}

package com.xfyuao.util;

import java.util.UUID;
/**
 * 生成学生和老师的uuid卡号
 * */
public class CardUtil {
    public static String getUUID(){
        String uuid= UUID.randomUUID().toString().replace("-","");
        return  uuid;
    }
    public static String getStudentCard(){
        return  "s"+getUUID();
    }
    public static String getTeacherCard(){
        return  "t"+getUUID();
    }
    public static String getEmpCard(){
        return  "e"+getUUID();
    }
}

package com.xfyuao.util;

import lombok.Data;

/***
 * 封装分页类
 * @author Administrator
 *
 * @param <T>
 */
@Data
public class PageUtil {
    
    private int page=1;//当前页数 
    private int limit=10;//每页显示多少条
    private int offset;//偏移量   从哪个下标开始，sql语句limit后的第一个数字

    /*
     * 其实不需要这样设置
     *     1.前端layui自己管理分页
     *     2.持久层jpa自己处理偏移量
     *     3.以上两者都只需要页码和条数就行了
     * */
    public void setPage(int page) {
        this.page = page;    
        this.offset=(this.page-1)*this.limit;
    }
    
}

package com.xfyuao.util;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
/**
 * 封装结果对象，经过springmvc转换成json对象返回给页面
 * */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Result {

    private Integer code; // 0成功
    private String msg;    // 响应失败状态码
    private Object data;
    private Long count;

    public Result(Integer code, String msg) {
        super();
        this.code = code;
        this.msg = msg;
    }

}

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>院系</title>
<link rel="stylesheet" type="text/css"
    href="js/layui-v2.5.4/css/layui.css" />
<script src="js/layui-v2.5.4/layui.js" type="text/javascript"
    charset="utf-8"></script>
</head>
<body>
    <!-- 条件区 -->
    <div class="layui-form-item"
        style="margin-top: 10px; margin-left: 10px">
        <form class="layui-form" method="post" onsubmit="return false;">
            <label class="layui-form-mid">部门名称</label>
            <div class="layui-input-inline" style="width: 200px;">
                <input id="dname" class="layui-input" placeholder="请输入部门名称">
            </div>
            <div class="layui-input-inline" style="width: 100px;">
                <button class="layui-btn" id="mySearch"
                    data-type="mySearchTableReload">搜索</button>
            </div>
        </form>
    </div>

    <!-- 顶部工具栏 -->
    <script type="text/html" id="topToolbar">
                <a href="dept.html" class="layui-btn layui-btn-sm"> 
                    <i class="layui-icon">&#x1002;</i>刷新
                </a>
                <a class="layui-btn layui-btn layui-btn-sm" lay-event="insertBtnEve">
                 <i class="layui-icon">&#xe608;</i> 添加
                </a>
    </script>
    <!--行内工具栏-->
    <script type="text/html" id="barDemo">
              <a class="layui-btn layui-btn-xs" lay-event="updateBtnEve">修改</a>
            <a class="layui-btn layui-btn-xs" lay-event="detailBtnEve">详情</a>
            <a class="layui-btn layui-btn-xs" lay-event="deleteBtnEve">删除</a>
        </script>
    <!-- 表格 -->
    <table class="layui-hide" id="myTable" lay-filter="myTableFil"></table>

    <!-- 增、改、单查共用页面，都不要id，否则和条件区重复了，直接调用serialize即可获取表单数据 -->
    <div id="myHtml" style="display: none; margin-top: 20px;">
        <form class="layui-form" id="myForm" lay-filter="myFormFil"
            onsubmit="return false;">
            <!-- 隐藏id -->
            <input type="hidden" id="deptNo" name="deptNo" value="0">
            <div class="layui-form-item">
                <label class="layui-form-label">部门名称:</label>
                <div class="layui-input-inline" style="width: 350px;">
                    <input type="text" name="dname" class="layui-input">
                </div>
            </div>
            <div class="layui-form-item">
                <label class="layui-form-label">办公地点:</label>
                <div class="layui-input-inline" style="width: 350px;">
                    <input type="text" name="loc" class="layui-input">
                </div>
            </div>
            <div class="layui-btn-container" style="text-align: center;"
                id="mySubmitDiv">
                <button class="layui-btn" lay-filter="mySubmitFil" lay-submit="">提交</button>
            </div>
        </form>
    </div>

    <script>
        /* 所有js代码都写这一行里面 */
        layui.use([ ‘table‘, ‘form‘ ], function() {
            var table = layui.table;
            var form = layui.form;
            var $ = layui.$;
            //渲染表格数据
            table.render({
                elem : ‘#myTable‘,
                url : ‘selectPageDept‘, //数据接口
                toolbar : ‘#topToolbar‘,
                method : ‘post‘,
                title : ‘部门列表‘,
                page : true, //开启分页
                cols : [ [ {
                    field : ‘deptNo‘,
                    title : ‘部门编号‘,
                    align : ‘center‘,
                    sort : true
                //开启排序，layui自己排
                }, {
                    field : ‘dname‘,
                    title : ‘部门名称‘,
                    align : ‘center‘
                }, {
                    field : ‘loc‘,
                    title : ‘办公地点‘,
                    align : ‘center‘
                }, {
                    fixed : ‘‘,
                    title : ‘操作‘,
                    align : ‘center‘,
                    toolbar : ‘#barDemo‘
                } ] ],
                id : "myTableReloadId"
            });
            /* 以layui格式创建函数，暂时只有一个函数：mySearchTableReload */
            active = {
                //定义搜索按钮函数
                mySearchTableReload : function() {
                    table.reload(‘myTableReloadId‘, {
                        where : {
                            //点搜索时以id形式获取表单数据，而不是提交表单
                            ‘dname‘ : $(‘#dname‘).val()
                        }
                    });
                }
            };
            //监听搜索按钮，执行mySearchTableReload方法
            $(‘#mySearch‘).on(‘click‘, function() {
                var type = $(this).data(‘type‘);
                active[type] ? active[type].call(this) : ‘‘;
            });
            //监听顶部工具栏事件，添加/修改按钮，点击弹出页面
            table.on(‘toolbar(myTableFil)‘, function(obj) {
                switch (obj.event) {
                case ‘insertBtnEve‘: {
                    $(‘#mySubmitDiv‘).css("display", "block");

                    //如果先点击了修改按钮，表单里有值了，这里重置一下
                    $(‘#myForm‘)[0].reset();
                    //重置不了id，这里手动重置一下
                    $(‘#deptNo‘).val(0);
                    layer.open({
                        type : 1,
                        title : ‘添加部门‘,
                        content : $("#myHtml"),
                        area : [ ‘500px‘, ‘400px‘ ]
                    });
                }
                    break;
                }
            });
            //监听行内工具条
            table.on(‘tool(myTableFil)‘, function(obj) {
                //获取该行数据
                var data = obj.data;
                if (obj.event === ‘updateBtnEve‘) {
                    $(‘#mySubmitDiv‘).css("display", "block");
                    form.val("myFormFil", data);
                    edit_index = layer.open({
                        type : 1,
                        title : ‘您正在修改‘ + data.dname + ‘的信息‘,
                        content : $("#myHtml"),
                        scrollbar : true, /* 滚动条 */
                        resize : true, /* 是否允许拉伸 */
                        area : [ ‘600px‘, ‘300px‘ ]
                    });
                } else if (obj.event === ‘detailBtnEve‘) {
                    //隐藏提交按钮
                    $(‘#mySubmitDiv‘).css("display", "none");
                    form.val("myFormFil", data);
                    edit_index = layer.open({
                        type : 1,
                        title : ‘您正在查看‘ + data.dname + ‘的信息‘,
                        content : $("#myHtml"),
                        scrollbar : true, /* 滚动条 */
                        resize : true, /* 是否允许拉伸 */
                        area : [ ‘600px‘, ‘200px‘ ]
                    });
                } else if (obj.event === ‘deleteBtnEve‘) {
                    form.val("myFormFil", data);
                    console.log(data.deptNo);
                    layer.confirm(‘确认删除id为[‘ + data.deptNo + ‘]的信息吗?‘, function(index) {
                        $.post("deleteDept", {
                            "deptNo" : data.deptNo
                        }, function(res) {
                            console.log(res);
                            if (res.code == 0) {
                                layer.msg(res.msg, {
                                    icon : 1,
                                    time : 1000
                                }, function() {
                                    layer.close(layer.index);
                                    window.location.reload();
                                });
                            } else {
                                layer.msg(res.msg, {
                                    icon : 2,
                                    time : 1000
                                });
                            }
                        }, "json");
                        return false;
                    });
                }
            });

            //监听新增/修改页面的提交按钮
            form.on(‘submit(mySubmitFil)‘, function(data) {
                $(‘#mySubmitDiv‘).css("display", "block");
                var str = $("#myForm").serialize();//根据name属性获取表单数据
                console.log(str);
                //判断是添加还是修改
                var myUrl;
                if ($(‘#dname‘).val() != null) {//简单的做个输入判断，未输入提交无效
                    if ($(‘#deptNo‘).val() == "0") {//为0说明没赋值，说明是添加
                        myUrl = "insertDept";
                    } else {
                        myUrl = "updateDept";
                    }
                }
                $.post(myUrl, str, function(res) {
                    if (res.code == 0) {
                        //根据后台提示信息弹出msg
                        layer.msg(res.msg, {
                            icon : 1,
                            time : 1000
                        }, function() {
                            layer.close(layer.index);
                            window.location.reload();
                        });
                    } else {
                        layer.msg(res.msg, {
                            icon : 5,
                            time : 1000
                        });
                    }
                }, "json");
            });
        });
    </script>
</body>
</html>

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<link rel="stylesheet" type="text/css"
    href="js/layui-v2.5.4/css/layui.css" />
<script src="js/layui-v2.5.4/layui.js" type="text/javascript"
    charset="utf-8"></script>
</head>
<body>
    <!-- 条件区 -->
    <div class="layui-form-item"
        style="margin-top: 10px; margin-left: 10px">
        <form class="layui-form" method="post" onsubmit="return false;">
            <label class="layui-form-mid">姓名:</label>
            <div class="layui-input-inline" style="width: 100px;">
                <input type="text" id="ename" autocomplete="off" class="layui-input"
                    placeholder="请输入姓名">
            </div>
            <label class="layui-form-mid">部门</label>
            <div class="layui-input-inline" style="width: 100px;">
                <select id="dnameSeach">
                    <option value="">--请选择--</option>
                </select>
            </div>
            <label class="layui-form-mid">卡号:</label>
            <div class="layui-input-inline" style="width: 300px;">
                <input type="text" id="empCardNoSeach" autocomplete="off"
                    class="layui-input" placeholder="请输入卡号，一部分即可">
            </div>
            <label class="layui-form-mid">入职日期:</label>
            <div class="layui-input-inline" style="width: 200px;">
                <input id="hiredate" type="text" autocomplete="off"
                    class="layui-input" placeholder="请选择开始日期">
            </div>
            <div class="layui-input-inline" style="width: 200px;">
                <input id="hiredate2" type="text" autocomplete="off"
                    class="layui-input" placeholder="请选择结束日期">
            </div>
        </form>
        <button class="layui-btn" id="mySearch"
            data-type="mySearchTableReload">搜索</button>
        <button class="layui-btn" onclick="renovates()">刷新</button>
    </div>
    <script type="text/javascript">
        function renovates() {
            window.location.reload(true);
        }
    </script>
    <!-- 顶部工具栏 -->
    <script type="text/html" id="topToolbar">
                <a class="layui-btn layui-btn layui-btn-sm" lay-event="insertBtnEve">
                 <i class="layui-icon">&#xe608;</i> 添加
                </a>
    </script>
    <!--行内工具栏-->
    <script type="text/html" id="barDemo">
              <a class="layui-btn layui-btn-xs" lay-event="updateBtnEve">修改</a>
            <a class="layui-btn layui-btn-xs" lay-event="detailBtnEve">详情</a>
            <a class="layui-btn layui-btn-xs" lay-event="deleteBtnEve">删除</a>
        </script>
    <!-- 表格 -->
    <table class="layui-hide" id="myTable" lay-filter="myTableFil"></table>

    <!-- 增、改、单查共用页面，都不要id，否则和条件区重复了，直接调用serialize即可获取表单数据 -->
    <div id="myHtml" style="display: none; margin-top: 20px;">
        <form class="layui-form" id="myForm" lay-filter="myFormFil"
            onsubmit="return false;">
            <!-- 隐藏id -->
            <input type="hidden" id="empNo" name="empNo" value="0">
            <!-- 隐藏卡号栏，修改回显时显示 -->
            <div id="empCardNoSave" class="layui-form-item" style="display: none">
                <label class="layui-form-label">卡号:</label>
                <div class="layui-input-inline" style="width: 350px;">
                    <input type="text" name="empCardNo"
                        class="layui-input layui-disabled">
                </div>
            </div>
            <div class="layui-form-item">
                <label class="layui-form-label">姓名:</label>
                <div class="layui-input-inline" style="width: 350px;">
                    <input type="text" name="ename" class="layui-input">
                </div>
            </div>
            <div class="layui-form-item">
                <label class="layui-form-label">入职日期:</label>
                <div class="layui-input-inline" style="width: 350px;">
                    <input id="hiredateSave" type="text" name="hiredate"
                        class="layui-input">
                </div>
            </div>
            <div class="layui-form-item">
                <label class="layui-form-label">状态:</label>
                <div class="layui-input-inline" style="width: 350px;">
                    <input type="radio" name="state" value="0" title="在职" checked>
                    <input type="radio" name="state" value="1" title="离职">
                </div>
            </div>
            <div class="layui-form-item">
                <label class="layui-form-label">部门:</label>
                <div class="layui-input-inline" style="width: 150px;">
                    <select id="dnameSave" name="dept.deptNo">
                        <option value="">请选择</option>
                    </select>
                </div>
            </div>
            <div class="layui-form-item">
                <label class="layui-form-label">备注:</label>
                <div class="layui-input-inline" style="width: 350px;">
                    <input type="text" name="remake" class="layui-input">
                </div>
            </div>
            <div class="layui-btn-container" style="text-align: center;"
                id="mySubmitDiv">
                <button class="layui-btn" lay-filter="mySubmitFil" lay-submit="">提交</button>
            </div>
        </form>
    </div>

    <script>
        /* 所有js代码都写这一行里面 */
        layui.use([ ‘table‘, ‘form‘, ‘laydate‘ ], function() {
            var table = layui.table;
            var form = layui.form;
            var laydate = layui.laydate;
            var $ = layui.$;
            //绑定日期插件
            laydate.render({
                elem : ‘#hiredate‘, //开始日期
                type : ‘datetime‘
            });
            laydate.render({
                elem : ‘#hiredate2‘, //结束日期
                type : ‘datetime‘
            });
            laydate.render({
                elem : ‘#hiredateSave‘, //save日期
                type : ‘datetime‘
            });
            //渲染表格数据
            table.render({
                elem : ‘#myTable‘,
                url : ‘selectPageEmp‘, //数据接口
                toolbar : ‘#topToolbar‘,
                method : ‘post‘,
                title : ‘教师表‘,
                page : true, //开启分页
                cols : [ [ {
                    field : ‘empNo‘,
                    title : ‘编号‘,
                    width : ‘10%‘,
                    align : ‘center‘,
                    sort : true
                //开启排序，layui自己排
                }, {
                    field : ‘ename‘,
                    title : ‘姓名‘,
                    width : ‘10%‘,
                    align : ‘center‘
                }, {
                    field : ‘empCardNo‘,
                    title : ‘卡号‘,
                    width : ‘30%‘,
                    align : ‘center‘
                }, {
                    field : ‘dname‘,
                    title : ‘部门名称‘,
                    width : ‘10%‘,
                    align : ‘center‘,
                    templet : function(d) {
                        return d.dept.dname
                    }
                }, {
                    field : ‘state‘,
                    title : ‘状态‘,
                    width : ‘10%‘,
                    align : ‘center‘,
                    templet : function(d) {
                        if (d.state == 0) {
                            return "在职";
                        } else if (d.state == 1) {
                            return "离职";
                        } else {
                            return "异常";
                        }
                    }
                }, {
                    field : ‘remake‘,
                    title : ‘备注‘,
                    width : ‘10%‘,
                    align : ‘center‘
                }, {
                    fixed : ‘‘,
                    title : ‘操作‘,
                    width : ‘15%‘,
                    align : ‘center‘,
                    toolbar : ‘#barDemo‘
                } ] ],
                id : "myTableReloadId"
            });
            /* 以layui格式创建函数，暂时只有一个函数：mySearchTableReload */
            active = {
                mySearchTableReload : function() {
                    table.reload(‘myTableReloadId‘, {
                        where : {
                            ‘ename‘ : $(‘#ename‘).val(),
                            ‘empCardNo‘ : $(‘#empCardNoSeach‘).val(),
                            ‘hiredate‘ : $(‘#hiredate‘).val(),
                            ‘hiredate2‘ : $(‘#hiredate2‘).val(),
                            ‘dept.deptNo‘ : $(‘#dnameSeach‘).val()
                        }
                    });
                }
            };
            //监听搜索按钮，执行mySearchTableReload方法
            $(‘#mySearch‘).on(‘click‘, function() {
                var type = $(this).data(‘type‘);
                active[type] ? active[type].call(this) : ‘‘;
            });
            $.post("selectAllDept", function(res) {
                var shtml = "<option></option>";
                $.each(res, function(index, value) {
                    shtml += ‘<option value="‘ + value.deptNo + ‘" > ‘ + value.dname + ‘</option>‘;
                });
                $(‘#dnameSeach‘).html(shtml);
                $(‘#dnameSave‘).html(shtml);
                form.render(‘select‘); //刷新select选择框渲染
            }, "json");
            //监听顶部工具栏事件，添加/修改按钮，点击弹出页面
            table.on(‘toolbar(myTableFil)‘, function(obj) {
                switch (obj.event) {
                case ‘insertBtnEve‘: {
                    $(‘#mySubmitDiv‘).css("display", "block");
                    //如果先点击了修改按钮，表单里有值了，这里重置一下
                    $(‘#myForm‘)[0].reset();
                    $(‘#myformselect‘).val("");
                    //重置不了id，这里手动重置一下
                    $(‘#empNo‘).val(0);
                    layer.open({
                        type : 1,
                        title : ‘添加页面‘,
                        content : $("#myHtml"),
                        area : [ ‘500px‘, ‘500px‘ ]
                    });
                }
                    break;
                }

            });
            table.on(‘tool(myTableFil)‘, function(obj) {
                var data = obj.data;
                if (obj.event === ‘updateBtnEve‘) {
                    //异步请求到所有部门，res就是返回的全部部门集合
                    $.post("selectAllDept", function(res) {
                        var shtml = "<option></option>";
                        $.each(res, function(index, value) {
                            //如果选中的这行的部门 和 所有的部门中的某个部门一致
                            if (data.dept.deptNo == value.deptNo) {
                                shtml += ‘<option value="‘ + value.deptNo + ‘" selected > ‘ + value.dname + ‘</option>‘;
                            } else {
                                shtml += ‘<option value="‘ + value.deptNo + ‘" > ‘ + value.dname + ‘</option>‘;
                            }
                        });
                        $(‘#dnameSave‘).html(shtml);
                        form.render(‘select‘); //刷新select选择框渲染
                    }, "json");
                    $(‘#empCardNoSave‘).css("display", "block");
                    $(‘#mySubmitDiv‘).css("display", "block");
                    form.val("myFormFil", data);
                    edit_index = layer.open({
                        type : 1,
                        title : ‘您正在修改‘ + data.ename + ‘的信息‘,
                        content : $("#myHtml"),
                        scrollbar : true, /* 滚动条 */
                        resize : true, /* 是否允许拉伸 */
                        area : [ ‘600px‘, ‘500px‘ ]
                    });
                } else if (obj.event === ‘detailBtnEve‘) {
                    //隐藏提交按钮
                    $(‘#mySubmitDiv‘).css("display", "none");
                    form.val("myFormFil", data);
                    edit_index = layer.open({
                        type : 1,
                        title : ‘您正在查看‘ + data.ename + ‘的信息‘,
                        content : $("#myHtml"),
                        scrollbar : true, /* 滚动条 */
                        resize : true, /* 是否允许拉伸 */
                        area : [ ‘600px‘, ‘400px‘ ]
                    });
                } else if (obj.event === ‘deleteBtnEve‘) {
                    layer.confirm(‘确认删除id为[‘ + data.empNo + ‘]的信息吗?‘, function(index) {
                        $.post("deleteEmp", {
                            "empNo" : data.empNo,
                        }, function(res) {
                            if (res.code == 0) {
                                layer.msg(res.msg, {
                                    icon : 1,
                                    time : 1000
                                }, function() {
                                    layer.close(layer.index);
                                    window.location.reload();
                                });
                            } else {
                                layer.msg(res.msg, {
                                    icon : 2,
                                    time : 1000
                                });
                            }
                        }, "json");
                    });
                }
            });

            //监听新增/修改页面的提交按钮
            form.on(‘submit(mySubmitFil)‘, function(data) {
                $(‘#mySubmitDiv‘).css("display", "block");
                console.log(data.field);
                //判断是添加还是修改
                var myUrl;
                if ($(‘#ename‘).val() != null) {
                    if ($(‘#empNo‘).val() == "0") {//为0说明没赋值，说明是添加
                        myUrl = "insertEmp";
                    } else {
                        myUrl = "updateEmp";
                    }
                }
                $.post(myUrl, data.field, function(res) {
                    if (res.code == 0) {
                        //根据后台提示信息弹出msg
                        layer.msg(res.msg, {
                            icon : 1,
                            time : 1000
                        }, function() {
                            layer.close(layer.index);
                            window.location.reload();
                        });
                    } else {
                        layer.msg(res.msg, {
                            icon : 5,
                            time : 1000
                        });
                    }
                }, "json");
            });
        });
    </script>
</body>
</html>