Spring+Mybatis整合开发（Mapper接口方式开发）实现简单的增删改查

相关jar包下载【链接：https://pan.baidu.com/s/1qJg8VjwnAqZt0GEq6Z258A?pwd=5hwd
提取码：5hwd 】
复制这段内容后打开百度网盘手机App，操作更方便哦
1、创建数据库并插入几条数据

CREATE TABLE `t_user` (
`id`  int NOT NULL AUTO_INCREMENT,
`username`  varchar(255) NULL ,
`jobs`  varchar(255) NULL ,
`phone`  varchar(255) NULL ,
PRIMARY KEY (`id`)
)
;

2、创建db.properties文件
maxTotal：最大连接数，maxIdle：最大空闲连接数，initialSize：初始化连接数

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/db_mybatis
jdbc.username=root
jdbc.password=root
jdbc.maxTotal=30
jdbc.maxIdle=10
jdbc.initialSize=5

3、创建applicationContext.xml配置文件

<?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:aop="http://www.springframework.org/schema/aop"
        xmlns:tx="http://www.springframework.org/schema/tx"
        xmlns:context="http://www.springframework.org/schema/context"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
        		http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
        		http://www.springframework.org/schema/tx
        		http://www.springframework.org/schema/tx/spring-tx-4.3.xsd
        		http://www.springframework.org/schema/context
        		http://www.springframework.org/schema/context/spring-context-4.3.xsd
        		http://www.springframework.org/schema/aop
        		http://www.springframework.org/schema/aop/spring-aop-4.3.xsd">
        <!-- 读取db.properties -->
        <context:property-placeholder location="classpath:db.properties" />
        <!-- 配置数据源 -->
        <bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource">
        <!-- 数据库驱动 -->
        <property name="driverClassName" value="${jdbc.driver}"  />
        <!-- 连接数据库的url -->
        <property name="url" value="${jdbc.url}" />
        <!-- 连接数据库的用户名 -->
        <property name="username" value="${jdbc.username}" />
        <!-- 连接数据库的密码 -->
        <property name="password" value="${jdbc.password}" />
        <!-- 最大连接数 -->
        <property name="maxTotal" value="${jdbc.maxTotal}" />
        <!-- 最大闲置连接 -->
        <property name="maxIdle" value="${jdbc.maxIdle}" />
        <!-- 初始化连接数 -->
        <property  name="initialSize" value="${jdbc.initialSize}" />
        </bean>
        <!-- 事务管理器，依赖于数据源 -->
        <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
        </bean>
        <!-- 注册事务管理器驱动，开启事务注解 -->
        <tx:annotation-driven  transaction-manager="transactionManager"  />
        <!-- 配置mybatis工厂 -->
        <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 注入数据源 -->
        <property name="dataSource" ref="dataSource" />
        <!-- 指定核心配置文件位置 -->
        <property name="configLocation" value="classpath:mybatis-config.xml" />
        </bean>
         <!-- 实例化Dao -->
        <bean id="userDao" class="com.ssm.dao.impl.UserDaoImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
        </bean>
        <!-- mapper代理开发（基于MapperFactoryBean） -->
        <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        	<property name="mapperInterface" value="com.ssm.mapper.UserMapper" />
        	<property name="sqlSessionFactory" ref="sqlSessionFactory" />
        </bean>
         
         <!-- mapper代理开发（基于MapperScannerConfigurer） -->
          <!-- 
         <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
         	<property name="basePackage" value="com.ssm.mapper" />
         </bean>
       --> 
       </beans>

3、mybatis-config.xml

<?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>
	<!-- 配置别名 -->
	<typeAliases>
	<package name="com.ssm.po" />
	</typeAliases>
	<!-- 配置mapper的位置 -->
	<mappers>
		<mapper resource="com/ssm/mapper/UserMapper.xml" />
	</mappers>
</configuration>

4、在com.ssm.po包中创建User

package com.ssm.po;

public class User {
	private Integer id;
	private String username;
	private String jobs;
	private String phone;
	public Integer getId() {
		return id;
	}
	public String getUsername() {
		return username;
	}
	public String getJobs() {
		return jobs;
	}
	public String getPhone() {
		return phone;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public void setJobs(String jobs) {
		this.jobs = jobs;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", username=" + username + ", jobs=" + jobs + ", phone=" + phone + "]";
	}
	
}

5、在com.ssm.mapper下创建UserMapper接口及对应的映射文件（名字要相同）

package com.ssm.mapper;

import com.ssm.po.User;

public interface UserMapper {
//查找
	public User findUserById(Integer id);
	//添加
	public int insertUser(User user);
	//更新
	public int updateUserById(User user);
	//删除
	public int deleteUser(Integer id);
}

UserMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
	"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
	<mapper namespace="com.ssm.mapper.UserMapper">
	<!-- 通过编号获取信息 -->
	<select id="findUserById" parameterType="Integer" resultType="com.ssm.po.User">
	select * from t_user where id=#{id}
	</select>
	<!-- 添加用户信息 -->
	<insert id="insertUser" parameterType="com.ssm.po.User" >
	insert into t_user(username,jobs,phone) values(#{username},#{jobs},#{phone})
	</insert>
	<!-- 更新用户信息 -->
	<update id="updateUserById"  parameterType="com.ssm.po.User" >
	update t_user set username=#{username},jobs=#{jobs},phone=#{phone} where id=#{id}
	</update>
	<!-- 删除用户信息 -->
	<delete id="deleteUser" parameterType="Integer" >
	delete from t_user where id=#{id}
	</delete>
	</mapper>

select元素要有parameterType属性以及resultType属性，因为查完返回查到的信息。
而insert、update、delete不需要resultType属性。还要注意这几个元素的parameterType属性值，传入的语句参数不同。最重要的是要保证他们的id要与你在UserMapper中写的方法名一致，最好复制粘贴。

Spring_MyBatis_Test测试类

package com.ssm.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.ssm.dao.UserDao;
import com.ssm.mapper.UserMapper;
import com.ssm.po.User;

public class Spring_MyBatis_Test {
	@Test
	public void findUserByIdTest(){
		//1、初始化spring容器，加载配置文件
		ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
		//2、通过容器获得userDao实例
		UserDao userDao=(UserDao)applicationContext.getBean("userDao");
		//调用UserDao接口查询方法（id为2）
		User user=userDao.findUserById(2);
		System.out.println(user.toString());
	}
	@Test
	public void findUserByIdTest2(){
		ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
		UserMapper userMapper=(UserMapper) applicationContext.getBean("userMapper");
		User user=userMapper.findUserById(2);
		System.out.println(user);
	}
	@Test
	public void insertUserTest(){
		ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
		UserMapper userMapper=(UserMapper) applicationContext.getBean("userMapper");
		User user=new User();
		user.setUsername("hqx2");
		user.setJobs("teaccher");
		user.setPhone("123456789");
	userMapper.insertUser(user);
		
	}
	@Test
	public void insertUserTest1(){
		ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
		//2、通过容器获得userDao实例
		UserDao userDao=(UserDao)applicationContext.getBean("userDao");
		User user=new User();
		user.setUsername("hqx1");
		user.setJobs("teaccher");
		user.setPhone("123456789");
		userDao.insertUser(user);
	}
	@Test
	public void updateUser(){
		ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
		UserMapper userMapper=(UserMapper) applicationContext.getBean("userMapper");
		User user=new User();
		user.setUsername("11");
		user.setJobs("11");
		user.setPhone("11");
		user.setId(2);
		userMapper.updateUserById(user);
	}
	@Test
	public void deleteUserTest(){
		ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
		UserMapper userMapper=(UserMapper) applicationContext.getBean("userMapper");
		userMapper.deleteUser(2);
		
	}
}

通过Dao接口方式开发与Mapper接口方式开发都能够实现，读者可自行测试。
但Mapper的开发方式更加简洁，代码比其少。
以下是一些注意事项：
1、在Mapper开发时，要保证Mapper接口名与Mapper.xml映射文件名一致
2、要将Mapper.xml文件的namespace与Mapper接口类路径一致（接口与映射文件要在一个包下）
项目总体架构