Mybatis实现Mapper动态代理方式详解

<?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="cn.itcast.mybatis.mapper.UserMapper"> 
<!-- 根据id获取用户信息 --> 
 <select id="findUserById" parameterType="int" resultType="cn.itcast.mybatis.po.User"> 
  select * from user where id = #{id} 
 </select> 
<!-- 自定义条件查询用户列表 --> 
 <select id="findUserByUsername" parameterType="java.lang.String" 
   resultType="cn.itcast.mybatis.po.User"> 
  select * from user where username like '%${value}%' 
 </select> 
<!-- 添加用户 --> 
 <insert id="insertUser" parameterType="cn.itcast.mybatis.po.User"> 
 <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer"> 
  select LAST_INSERT_ID() 
 </selectKey> 
  insert into user(username,birthday,sex,address) 
  values(#{username},#{birthday},#{sex},#{address}) 
 </insert> 
 
</mapper> 

/** 
 * 用户管理mapper 
 */ 
Public interface UserMapper { 
 //根据用户id查询用户信息 
 public User findUserById(int id) throws Exception; 
 //查询用户列表 
 public List<User> findUserByUsername(String username) throws Exception; 
 //添加用户信息 
 public void insertUser(User user)throws Exception; 
} 

<!-- 加载映射文件 --> 
 <mappers> 
 <mapper resource="mapper/UserMapper.xml"/> 
 </mappers> 

Public class UserMapperTest extends TestCase { 
 
 private SqlSessionFactory sqlSessionFactory; 
  
 protected void setUp() throws Exception { 
  //mybatis配置文件 
  String resource = "sqlMapConfig.xml"; 
  InputStream inputStream = Resources.getResourceAsStream(resource); 
  //使用SqlSessionFactoryBuilder创建sessionFactory 
  sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); 
 } 
 
  
 Public void testFindUserById() throws Exception { 
  //获取session 
  SqlSession session = sqlSessionFactory.openSession(); 
  //获取mapper接口的代理对象 
  UserMapper userMapper = session.getMapper(UserMapper.class); 
  //调用代理对象方法 
  User user = userMapper.findUserById(1); 
  System.out.println(user); 
  //关闭session 
  session.close(); 
   
 } 
 @Test 
 public void testFindUserByUsername() throws Exception { 
  SqlSession sqlSession = sqlSessionFactory.openSession(); 
  UserMapper userMapper = sqlSession.getMapper(UserMapper.class); 
  List<User> list = userMapper.findUserByUsername("张"); 
  System.out.println(list.size()); 
 
 } 
Public void testInsertUser() throws Exception { 
  //获取session 
  SqlSession session = sqlSessionFactory.openSession(); 
  //获取mapper接口的代理对象 
  UserMapper userMapper = session.getMapper(UserMapper.class); 
  //要添加的数据 
  User user = new User(); 
  user.setUsername("张三"); 
  user.setBirthday(new Date()); 
  user.setSex("1"); 
  user.setAddress("北京市"); 
  //通过mapper接口添加用户 
  userMapper.insertUser(user); 
  //提交 
  session.commit(); 
  //关闭session 
  session.close(); 
 } 
  
 
}