MyBatis 与 Spring 整合 MyBatis 与 Spring 的完美整合方法

<?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"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
  http://www.springframework.org/schema/beans/spring-beans.xsd
  http://www.springframework.org/schema/context
  http://www.springframework.org/schema/context/spring-context.xsd">
 <!-- 加载配置文件 -->
 <context:property-placeholder location="classpath:db.properties"/>
 <!-- 配置数据源 -->
 <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
  <property name="driverClassName" value="${jdbc.driver}"/>
  <property name="url" value="${jdbc.url}"/>
  <property name="username" value="${jdbc.username}"/>
  <property name="password" value="${jdbc.password}"/>
 </bean>
 <!-- sqlSessionFactory -->
 <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
  <!-- 加载 MyBatis 的配置文件 -->
  <property name="configLocation" value="mybatis/SqlMapConfig.xml"/>
  <!-- 数据源 -->
  <property name="dataSource" ref="dataSource"/>
 </bean>
</beans>

<?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>
 <!-- settings -->
 <settings>
  <!-- 打开延迟加载的开关 -->
  <setting name="lazyLoadingEnabled" value="true"/>
  <!-- 将积极加载改为消极加载（即按需加载） -->
  <setting name="aggressiveLazyLoading" value="false"/>
  <!-- 打开全局缓存开关（二级缓存）默认值就是 true -->
  <setting name="cacheEnabled" value="true"/>
 </settings>
 <!-- 别名定义 -->
 <typeAliases>
  <package name="cn.wmyskxz.pojo"/>
 </typeAliases>
 <!-- 加载映射文件 -->
 <mappers>
  <!-- 通过 resource 方法一次加载一个映射文件 -->
  <mapper resource="sqlmap/UserMapper.xml"/>
  <!-- 批量加载mapper -->
  <package name="cn.wmyskxz.mapper"/>
 </mappers>
</configuration>

<?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="test">
 <select id="findUserById" parameterType="_int" resultType="user">
 SELECT * FROM USER WHERE id = #{id}
</select>
</mapper>

package cn.wmyskxz.pojo;
import java.io.Serializable;
public class User implements Serializable {
 private int id;
 private String username;
 /* getter and setter */
}

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?characterEncoding=UTF-8
jdbc.username=root
jdbc.password=root

# Global logging configuration
# 在开发环境下日志级别要设置成 DEBUG ，生产环境设为 INFO 或 ERROR
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

package cn.wmyskxz.dao;
import cn.wmyskxz.pojo.User;
public interface UserDAO {
 // 根据 id 查询用户信息
 public User findUserById(int id) throws Exception;
}

package cn.wmyskxz.dao;
import cn.wmyskxz.pojo.User;
import org.apache.ibatis.session.SqlSession;
import org.mybatis.spring.support.SqlSessionDaoSupport;
public class UserDAOImpl extends SqlSessionDaoSupport implements UserDAO {
 @Override
 public User findUserById(int id) throws Exception {
  // 继承 SqlSessionDaoSupport 类，通过 this.getSqlSession() 得到 sqlSession
  SqlSession sqlSession = this.getSqlSession();
  User user = sqlSession.selectOne("test.findUserById", id);
  return user;
 }
}

<!-- 原始 DAO 接口 -->
<bean id="userDAO" class="cn.wmyskxz.dao.UserDAOImpl">
 <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>

package cn.wmyskxz.test;
import cn.wmyskxz.dao.UserDAO;
import cn.wmyskxz.pojo.User;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class UserServiceTest {
 private ApplicationContext applicationContext;
 // 在执行测试方法之前首先获取 Spring 配置文件对象
 // 注解@Before在执行本类所有测试方法之前先调用这个方法
 @Before
 public void setup() throws Exception {
  applicationContext = new
    ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
 }
 @Test
 public void testFindUserById() throws Exception {
  // 通过配置资源对象获取 userDAO 对象
  UserDAO userDAO = (UserDAO) applicationContext.getBean("userDAO");
  // 调用 UserDAO 的方法
  User user = userDAO.findUserById(1);
  // 输出用户信息
  System.out.println(user.getId() + ":" + user.getUsername());
 }
}

package cn.wmyskxz.mapper;

import cn.wmyskxz.pojo.User;
import org.apache.ibatis.annotations.Select;

public interface UserQueryMapper {

 @Select("SELECT * FROM USER WHERE id = #{id}")
 public User findUserById(int id) throws Exception;
}

<!-- Mapper 扫描器 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
 <!-- 扫描 cn.wmyskxz.mapper 包下的组件 -->
 <property name="basePackage" value="cn.wmyskxz.mapper"/>
</bean>

package cn.wmyskxz.test;
import cn.wmyskxz.mapper.UserQueryMapper;
import cn.wmyskxz.pojo.User;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class UserServiceTest {
 private ApplicationContext applicationContext;
 // 在执行测试方法之前首先获取 Spring 配置文件对象
 // 注解@Before在执行本类所有测试方法之前先调用这个方法
 @Before
 public void setup() throws Exception {
  applicationContext = new
    ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
 }
 @Test
 public void testFindUserById() throws Exception {
  // 通过配置资源对象获取 userDAO 对象
  UserQueryMapper userQueryMapper = (UserQueryMapper) applicationContext.getBean("userQueryMapper");
  // 调用 UserDAO 的方法
  User user = userQueryMapper.findUserById(1);
  // 输出用户信息
  System.out.println(user.getId() + ":" + user.getUsername());
 }
}