标签：abstract get key 命名 row integer html frame mon
前提是MyBatis环境部署好了，参考地址：
https://www.cnblogs.com/package-java/p/10316536.html
为了方便演示，我提前在数据库插入了数据方便查询
1. 创建新的数据库`tedu_ums`；
CREATE DATABASE tedu_ums;
2. 在新数据库中创建数据表`t_user`，表中至少包含id, username, password, age, phone, email这6个属性；
USE tedu_ums;
CREATE TABLE t_user (
id INT AUTO_INCREMENT,
username VARCHAR(20) UNIQUE NOT NULL,
password VARCHAR(20) NOT NULL,
age INT,
phone VARCHAR(20),
email VARCHAR(50),
PRIMARY KEY(id)
) DEFAULT CHARSET=utf8;
3. 添加不少于10条数据；
INSERT INTO t_user
(username, password, age, phone, email)
VALUES
(‘root‘, ‘1234‘, 18, ‘13800138001‘, ‘root@tedu.cn‘),
(‘admin‘, ‘4567‘, 19, ‘13800138002‘, ‘admin@tedu.cn‘),
(‘jack‘, ‘1234‘, 20, ‘13800138003‘, ‘jack@tedu.cn‘),
(‘tom‘, ‘1234‘, 22, ‘13800138010‘, ‘tom@tedu.cn‘),
(‘jerry‘, ‘1234‘, 25, ‘13800138011‘, ‘jerry@tedu.cn‘),
(‘rose‘, ‘1234‘, 21, ‘13800138004‘, ‘rose@tedu.cn‘),
(‘mike‘, ‘1234‘, 22, ‘13800138005‘, ‘mike@tedu.cn‘),
(‘lily‘, ‘1234‘, 23, ‘13800138006‘, ‘lily@tedu.cn‘),
(‘lucy‘, ‘1234‘, 24, ‘13800138007‘, ‘lucy@tedu.cn‘),
(‘mary‘, ‘1234‘, 25, ‘13800138008‘, ‘mary@tedu.cn‘),
(‘alex‘, ‘1234‘, 26, ‘13800138009‘, ‘alex@tedu.cn‘);
4. 查询所有数据；
SELECT id,username,password,age,phone,email FROM t_user;
一、创建实体类
每张数据表都应该有1个对应的实体类，所以，创建`cn.tedu.mybatis.entity.User`类，属性的数量与类型请参考数据表的设计：
package cn.tedu.mybatis.entity; public class User { private Integer id; private String username; private String password; private Integer age; private String phone; private String email; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } @Override public String toString() { return "User [id=" + id + ", username=" + username + ", password=" + password + ", age=" + age + ", phone=" + phone + ", email=" + email + "]"; } }
二、创建接口，声明抽象方法
创建`cn.tedu.mybatis.mapper.UserMapper`接口，并在接口中声明“插入用户数据”的抽象方法：
package cn.tedu.mybatis.mapper; import cn.tedu.mybatis.entity.User; public interface UserMapper { Integer addnew(User user);//增 User findById(Integer id);//查 Integer updatenew(User user);//改 Integer deletenew(Integer id);//删 }
关于抽象方法，在MyBatis中，执行的操作如果是增、删、改，返回值均使用`Integer`，表示受影响的行数；方法的名称可以自定义，只要不违反Java的命名规则即可，另外，不允许在接口中使用重载机制；参数也可以自定义，如果执行的是增加操作，参数应该是与数据表对应的实体类的类型。
三、配置接口所在的包并配置配置XML文件的位置与数据源
1、在MyBatis中，通过`MapperScannerConfigurer`类扫描持久层接口的，所以，应该在`spring-dao.xml`文件中进行配置：
2、MyBatis通过`SqlSessionFactoryBean`获取数据源，并且扫描配置了SQL语句的XML文件，最终由MyBatis框架来执行SQL语句，所以，需要在`spring-dao.xml`中配置`SqlSessionFactoryBean`：
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:util="http://www.springframework.org/schema/util" xmlns:jpa="http://www.springframework.org/schema/data/jpa" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd"> <!-- 加载数据库的配置文件 --> <util:properties id="dbConfig" location="classpath:db.properties"></util:properties> <!-- 配置数据源 --> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"> <property name="url" value="#{dbConfig.url}"></property> <property name="driverClassName" value="#{dbConfig.driver}"></property> <property name="username" value="#{dbConfig.username}"></property> <property name="password" value="#{dbConfig.password}"></property> <property name="initialSize" value="#{dbConfig.initialSize}"></property> <property name="maxActive" value="#{dbConfig.maxActive}"></property> </bean> <!-- 扫描持久层接口 --> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <!-- 配置接口文件所在的包 --> <property name="basePackage" value="cn.tedu.mybatis.mapper"></property> </bean> <!-- 或取数据源 --> <bean class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource"></property> <property name="mapperLocations" value="classpath:mappers/*.xml"></property> </bean> </beans>
四、在XML中配置接口方法对应的SQL语句
在`src/main/resources`下创建名为`mappers`文件夹，创建名为UserMapper.xml的文件
根节点必须是`<mapper>`，且根节点的`namespace`表示对应的接口文件，然后，添加子节点，以对应接口中的抽象方法：
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd"> <!-- 根节点必须是mapper --> <!-- namespace对应的接口文件 --> <mapper namespace="cn.tedu.mybatis.mapper.UserMapper"> <!-- 根据执行的操作类型选择节点 --> <!-- id:对应的抽象方法的方法名 --> <!-- 值：#{}括号里面的是User的属性名 --> <insert id="addnew"> INSERT INTO t_user( username,password,age,phone,email ) value( #{username},#{password},#{age},#{phone},#{email} ) </insert> <select id="findById" resultType="cn.tedu.mybatis.entity.User"> SELECT id,username,password,age,phone,email FROM t_user WHERE id=#{id} </select> <insert id="addnewone"> INSERT INTO t_user( username,password,age,phone,email ) value( #{username},#{password},#{age},#{phone},#{email} ) </insert> <update id="updatenew"> UPDATE t_user SET username=#{username}, password=#{password}, age = #{age}, phone = #{phone}, email=#{email} WHERE id=#{id} </update> <delete id="deletenew"> DELETE FROM t_user WHERE age=#{age} </delete> </mapper>
五、在测试类中测试
package web; import org.junit.After; import org.junit.Before; import org.junit.Test; import org.springframework.context.support.AbstractApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import cn.tedu.mybatis.entity.User; import cn.tedu.mybatis.mapper.UserMapper; public class TestDemo01 { AbstractApplicationContext ac; UserMapper mapper; @Before public void doBefore() { ac = new ClassPathXmlApplicationContext("spring-dao.xml"); mapper = ac.getBean("userMapper",UserMapper.class);//根据id或取对象 } @After public void doafter() { ac.close(); } /* 测试插入*/ @Test public void add() { User user = new User(); user.setUsername("学海无崖"); user.setPassword("12345600"); Integer row = mapper.addnew(user); System.out.println("row:"+row); } /* 测试查询*/ @Test public void findById() { Integer id=8; User user = mapper.findById(id); System.out.println(user); } /* 测试修改*/ @Test public void updatenew() { User user = new User(); user.setUsername("小珠佩琦"); user.setPassword("5548"); user.setAge(18); user.setEmail("44@qq.com"); user.setPhone("448484"); user.setId(6); Integer num = mapper.updatenew(user); System.out.println("num:"+num); } /* 测试删除*/ @Test public void deletenew() { Integer age = 60; Integer row = mapper.deletenew(age); System.out.println("row:"+row); } }
标签：abstract get key 命名 row integer html frame mon
原文地址：https://www.cnblogs.com/package-java/p/10327215.html
