码迷，mamicode.com
首页 > 数据库 > 详细

小峰mybatis（4）mybatis使用注解配置sql映射器

时间：2017-04-12 10:07:44      阅读：340      评论：0      收藏：0      [点我收藏+]

标签：eid   ota   conf   this   play   学生   out   one   bsp   

主流开发还是使用xml来配置；使用注解配置比较快，但是不支持所有功能；有些功能还是得用配置文件；

一、基本映射语句：　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

@Inert

@Update

@Delete

@Select

二、结果集映射语句　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

项目结够：

技术分享

Student.java model实体类：

技术分享 
package com.cy.model;

public class Student{
    private Integer id;
    private String name;
    private Integer age;
    
    public Student(){
        
    }
    
    public Student(String name, Integer age){
        this.name = name;
        this.age = age;
    }
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
    }
    
    
    
}
View Code

mybatis-config.xml:

技术分享 
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <properties resource="jdbc.properties"/>
    <!-- 别名 -->
    <typeAliases>
        <package name="com.cy.model"/>
    </typeAliases>
    
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
                <dataSource type="POOLED">
                    <property name="driver" value="${jdbc.driverClassName}" />
                    <property name="url" value="${jdbc.url}" />
                    <property name="username" value="${jdbc.username}" />
                    <property name="password" value="${jdbc.password}" />
                </dataSource>
        </environment>
        <environment id="test">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driverClassName}" />
                <property name="url" value="${jdbc.url}" />
                <property name="username" value="${jdbc.username}" />
                <property name="password" value="${jdbc.password}" />
            </dataSource>
        </environment>
    </environments>
    
    <mappers>
        <package name="com.cy.mapper"/>
    </mappers>
</configuration>
View Code

StudentMapper.java 接口：

package com.cy.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Update;
import org.apache.ibatis.annotations.Select;

import com.cy.model.Student;

public interface StudentMapper {
    
    //插入
    @Insert("insert into t_student values(null, #{name}, #{age})")
    public int inertStudent(Student student);
    
    //更新
    @Update("update t_student set name=#{name}, age=#{age} where id = #{id}")
    public int updateStudent(Student stu);
    
    //删除
    @Delete("delete from t_student where id=#{id}")
    public int deleteStudent(int id);
    
    //根据id查找学生
    @Select("select * from t_student where id=#{id}")
    public Student getStudentById(Integer id);
    
    //查询所有学生  结果集映射  id主键列
    @Select("select * from t_student")
    @Results(
            {
                @Result(id=true,column="id",property="id"),
                @Result(column="name",property="name"),
                @Result(column="age",property="age")
            }
    )
    public List<Student> findStudents();

}

测试代码StudentTest.java:

package com.cy.service;


import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.cy.mapper.StudentMapper;
import com.cy.model.Student;
import com.cy.util.SqlSessionFactoryUtil;

public class StudentTest {
    private static Logger logger = Logger.getLogger(StudentTest.class);
    
    private SqlSession sqlSession=null;
    private StudentMapper studentMapper=null;
    
    @Before
    public void setUp() throws Exception {
        sqlSession=SqlSessionFactoryUtil.openSession();
        studentMapper=sqlSession.getMapper(StudentMapper.class);
    }
    
    @After
    public void tearDown() throws Exception {
        sqlSession.close();
    }
    
    @Test
    public void testInsertStudent() {
        logger.info("测试insertStudent");
        Student stu = new Student("cpp", 12);
        int count = studentMapper.inertStudent(stu);
        sqlSession.commit();
    }
    
    @Test
    public void testUpdateStudent() {
        logger.info("测试updateStudent");
        Student stu = new Student("cppp", 13);
        stu.setId(14);
        int count = studentMapper.updateStudent(stu);
        sqlSession.commit();
    }
    
    @Test
    public void testDeleteStudent() {
        logger.info("测试删除学生");
        int count = studentMapper.deleteStudent(14);
        sqlSession.commit();
    }
    
    @Test
    public void testGetById(){
        logger.info("根据id查找学生");
        Student stu = studentMapper.getStudentById(1);
        System.out.println(stu);
    }
    
    @Test
    public void testFindStudent() {
        logger.info("测试查询所有学生");
        List<Student> students = studentMapper.findStudents();
        for(Student student : students){
            System.out.println(student);
        }
    }
}

 

三、使用注解 一对一映射：　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

每个学生都有一个地址，一对一；
数据库中t_student和t_address：
技术分享
t_address:
技术分享
Student.java 实体：
技术分享 
package com.cy.model;

public class Student{
    private Integer id;
    private String name;
    private Integer age;
    private Address address;
    
    public Student(){
        
    }
    
    public Student(String name, Integer age){
        this.name = name;
        this.age = age;
    }
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    
    
    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", age=" + age
                + ", address=" + address + "]";
    }

    
    
}
View Code

Address.java 实体：

技术分享 
package com.cy.model;

public class Address {

    private Integer id;
    private String sheng;
    private String shi;
    private String qu;
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getSheng() {
        return sheng;
    }
    public void setSheng(String sheng) {
        this.sheng = sheng;
    }
    public String getShi() {
        return shi;
    }
    public void setShi(String shi) {
        this.shi = shi;
    }
    public String getQu() {
        return qu;
    }
    public void setQu(String qu) {
        this.qu = qu;
    }
    @Override
    public String toString() {
        return "Address [id=" + id + ", sheng=" + sheng + ", shi=" + shi
                + ", qu=" + qu + "]";
    }
    
    
}
View Code

StudentMapper.java接口：

//查询学生，带地址
    @Select("select * from t_student where id=#{id}")
    @Results(
            {
                @Result(id=true,column="id",property="id"),
                @Result(column="name",property="name"),
                @Result(column="age",property="age"),
                @Result(column="addressId",property="address",one=@One(select="com.cy.mapper.AddressMapper.findById"))
            }
    )
    public Student findStudentWithAddress(int id);

AddressMapper.java接口：

public interface AddressMapper {

    @Select("select * from t_address where id=#{id}")
    public Address findById(Integer id);

}

mybatis的实现是：在查找学生的时候，将addressId,传到AddressMapper.findById方法，根据这个addressId查找address；

测试代码：

@Test
    public void testFindStudentWithAddress() {
        logger.info("测试学生,带地址");
        Student student = studentMapper.findStudentWithAddress(15);
        System.out.println(student);
    }

console打印：

技术分享

 

四、使用注解，一对多映射　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

一个年级下有多个学生，多个学生属于一个年级，年级和学生是一对多；
Student.java:
技术分享 
package com.cy.model;

public class Student{
    private Integer id;
    private String name;
    private Integer age;
    private Address address;
    private Grade grade;
    
    public Student(){
        
    }
    
    public Student(String name, Integer age){
        this.name = name;
        this.age = age;
    }
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    
    
    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }
    

    public Grade getGrade() {
        return grade;
    }

    public void setGrade(Grade grade) {
        this.grade = grade;
    }

    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", age=" + age
                + ", address=" + address + ", grade=" + grade + "]";
    }

    

    
    
}
View Code

Grade.java:

技术分享 
package com.cy.model;

import java.util.List;

public class Grade {

    private Integer id;
    private String gradeName;
    private List<Student> students;
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getGradeName() {
        return gradeName;
    }
    public void setGradeName(String gradeName) {
        this.gradeName = gradeName;
    }
    public List<Student> getStudents() {
        return students;
    }
    public void setStudents(List<Student> students) {
        this.students = students;
    }
    @Override
    public String toString() {
        return "Grade [id=" + id + ", gradeName=" + gradeName +"]";
    }
    
    
}
View Code

数据库中表，t_student:

技术分享

t_grade:

技术分享

1)根据id查找年级，将年级下的学生也查出来：

GradeMapper.java:

public interface GradeMapper {
    
    //根据id查找年级，将年级下的学生也查出来
    @Select("select * from t_grade where id = #{id}")
    @Results(
            {
                @Result(id=true,column="id",property="id"),
                @Result(column="gradeName",property="gradeName"),
                @Result(column="id",property="students",many=@Many(select="com.cy.mapper.StudentMapper.findStudentByGradeId"))
            }
    )
    public Grade findById(Integer id);
}

StudentMapper.java:

//根据年级查找学生
    @Select("select * from t_student where gradeId=#{gradeId}")
    @Results(
            {
                @Result(id=true,column="id",property="id"),
                @Result(column="name",property="name"),
                @Result(column="age",property="age"),
                @Result(column="addressId",property="address",one=@One(select="com.cy.mapper.AddressMapper.findById"))
            }
    )
    public Student findStudentByGradeId(int gradeId);

测试代码：

//根据id查找年级，将年级下的学生也查出来
    @Test
    public void testFindGradeWithStudents() {
        logger.info("根据id查询年级(带学生)");
        Grade grade=gradeMapper.findById(1);
        System.out.println(grade);
        List<Student> studentList=grade.getStudents();
        for(Student student:studentList){
            System.out.println(student);
        }
    }

结果：

技术分享

 

2）根据id查询学生，将年级信息也查出来：

StudentMapper.java:

//根据id查询学生带地址   和 年级
    @Select("select * from t_student where id=#{id}")
    @Results(
            {
                @Result(id=true,column="id",property="id"),
                @Result(column="name",property="name"),
                @Result(column="age",property="age"),
                @Result(column="addressId",property="address",one=@One(select="com.cy.mapper.AddressMapper.findById")),
                @Result(column="gradeId",property="grade",one=@One(select="com.cy.mapper.GradeMapper.findById"))
            }
    )
    public Student findStudentWithAddressAndGrade(int id);

GradeMapper.java中的findById和上面1）中一样；

测试代码：

//根据id查询学生，带地址和年级
    @Test
    public void testSelectStudentWithAddressAndGrade() {
        logger.info("根据id查询学生(带地址、年级)");
        Student student=studentMapper.findStudentWithAddressAndGrade(1);
        System.out.println(student);
    }

打印结果：

技术分享

 

 

 

 

 

 

 

 

 

小峰mybatis（4）mybatis使用注解配置sql映射器

标签：eid   ota   conf   this   play   学生   out   one   bsp   

原文地址：http://www.cnblogs.com/tenWood/p/6697198.html
踩
(0)
赞
(0)
   
举报
评论 一句话评论（0）
登录后才能评论！
分享档案
更多>
2021年07月29日 (22)
2021年07月28日 (40)
2021年07月27日 (32)
2021年07月26日 (79)
2021年07月23日 (29)
2021年07月22日 (30)
2021年07月21日 (42)
2021年07月20日 (16)
2021年07月19日 (90)
2021年07月16日 (35)
周排行
mamicode.com排行更多图片
更多
友情链接
兰亭集智   国之画   百度统计   站长统计   阿里云   chrome插件   新版天听网
关于我们 - 联系我们 - 留言反馈
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码！