上面2章写了mybatis的基本操作，今天就写写mybatis的动态代理吧。

动态代理有4个基本原则：

1.userMapper.xml里面的namespace="cn.my.dao.UserDaoMapper"一定要和接口的包名+接口名一致

2.userMapper.xml里面的statementid值要和接口中的方法名一致

3.userMapper.xml里面的入参类型要和接口中方法的参数类型一致

4.userMapper.xml里面的返回类型要和接口中方法的返回类型一致

好了不废话直接上代码.

首先改造一下上一篇的代码，为了不修改user.xml，添加一个新的UserMapper.xml文件，然后修改部分代码

 

     
         
              select * from user where id=#{id}            
          
               
       
                    SELECT LAST_INSERT_ID()        
               INSERT INTO `user` (`username`,`birthday`,`sex`,`address`)         VALUES(#{username},#{birthday},#{sex},#{address})    
             
          
      
               UPDATE `user`         SET          `username` = #{username},          `birthday` = #{birthday},          `sex` = #{sex},          `address` = #{address}         WHERE `id` = #{id} ;    
          
          
      
               delete from user where id=#{id}    
      
     

 

第二步新增一个UserDaoMapper.java接口

package cn.my.dao;import cn.my.mybatis.entity.User;public interface UserDaoMapper {        public User findById(int id);    public void insert(User user);    public void update(User user);    public void delete(int id);}

 

第三步新增一个测试类TestUserMapper.java文件

 

package cn.my.test;import java.io.IOException;import java.io.InputStream;import java.util.Date;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import org.junit.Before;import org.junit.Test;import cn.my.dao.UserDaoMapper;import cn.my.mybatis.entity.User;public class TestUserMapper {    private SqlSessionFactory factory;    @Before    public void setUp() throws IOException{        String resource = "SqlMapConfig.xml";        InputStream inputStream = Resources.getResourceAsStream(resource);        factory = new SqlSessionFactoryBuilder().build(inputStream);    }        @Test      public void testFindById(){          SqlSession session = factory.openSession();        UserDaoMapper dao = session.getMapper(UserDaoMapper.class);//获取mybatis的动态代码实现接口对象        User user = dao.findById(10);        session.close();          System.out.println(user);      }      /**     * 新增用户     */    @Test      public void testInserUser(){          SqlSession session = factory.openSession();        User user = new User();        user.setAddress("许昌");        user.setUsername("曹操1");        user.setSex("男");        user.setBirthday(new Date());        UserDaoMapper dao = session.getMapper(UserDaoMapper.class);//获取mybatis的动态代码实现接口对象        dao.insert(user);         session.commit();        session.close();          System.out.println(user.getId());      }    /**     * 修改     */    @Test      public void testUpdateUser(){          SqlSession session = factory.openSession();        User user = new User();        user.setId(34);        user.setAddress("许昌1");        user.setUsername("曹操2");        user.setSex("女");        user.setBirthday(new Date());        UserDaoMapper dao = session.getMapper(UserDaoMapper.class);//获取mybatis的动态代码实现接口对象        dao.update(user);         session.commit();        session.close();      }      /**     * 删除     */    @Test      public void testDeleteUser(){          SqlSession session = factory.openSession();        UserDaoMapper dao = session.getMapper(UserDaoMapper.class);//获取mybatis的动态代码实现接口对象        dao.delete(34);         session.commit();        session.close();      }                 }

 

 

 

运行结果:

查询结果：User [id=10, username=张三, sex=1, birthday=Thu Jul 10 00:00:00 CST 2014, address=北京市]

新增结果：   　　打印结果：34

 

修改结果：

 

删除结果：

 

 以上修改为动态代理就已经修改好了。

下一章写sql动态标签

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