mybatis 详解（三）------入门实例（基于注解）

1、创建MySQL数据库：mybatisDemo和表：user

　　详情参考：mybatis 详解（二）------入门实例（基于XML） 一致

2、建立一个Java工程，并导入相应的jar包，具体目录如下

 　　详情参考：mybatis 详解（二）------入门实例（基于XML） 一致

3、在 MyBatisTest 工程中添加数据库配置文件 mybatis-configuration.xml

4、定义表所对应的实体类

5、定义操作 user 表的注解接口 UserMapper.java

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package com.ys.annocation; import org.apache.ibatis.annotations.Delete; import org.apache.ibatis.annotations.Insert; import org.apache.ibatis.annotations.Select; import org.apache.ibatis.annotations.Update; import com.ys.po.User; public interface UserMapper { //根据 id 查询 user 表数据 @Select ( "select * from user where id = #{id}" ) public User selectUserById( int id) throws Exception; //向 user 表插入一条数据 @Insert ( "insert into user(username,sex,birthday,address) value(#{username},#{sex},#{birthday},#{address})" ) public void insertUser(User user) throws Exception; //根据 id 修改 user 表数据 @Update ( "update user set username=#{username},sex=#{sex} where id=#{id}" ) public void updateUserById(User user) throws Exception; //根据 id 删除 user 表数据 @Delete ( "delete from user where id=#{id}" ) public void deleteUserById( int id) throws Exception; }

　　

6、向 mybatis-configuration.xml 配置文件中注册 UserMapper.java 文件

<mappers> <mapper class = "com.ys.annocation.UserMapper" /> </mappers>

 7、创建测试类

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package com.ys.test; import java.io.InputStream; 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 com.ys.annocation.UserMapper; import com.ys.po.User; public class UserAnnocationTest { //定义 SqlSession SqlSession session = null ; @Before public void init(){ //定义mybatis全局配置文件 String resource = "mybatis-configuration.xml" ; //加载 mybatis 全局配置文件 InputStream inputStream = CRUDTest. class .getClassLoader() .getResourceAsStream(resource); //构建sqlSession的工厂 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //根据 sqlSessionFactory 产生 session session = sessionFactory.openSession(); } //注解的增删改查方法测试 @Test public void testAnncationCRUD() throws Exception{ //根据session获取 UserMapper接口 UserMapper userMapper = session.getMapper(UserMapper. class ); //调用selectUserById()方法 User user = userMapper.selectUserById( 1 ); System.out.println(user); //调用  insertUser() 方法 User user1 = new User(); user1.setUsername( "aliks" ); user1.setSex( "不详" ); userMapper.insertUser(user1); //调用 updateUserById() 方法 User user2 = new User(); user2.setId( 6 ); user2.setUsername( "lbj" ); userMapper.updateUserById(user2); //调用 () 方法 userMapper.deleteUserById( 6 ); session.commit(); session.close(); } }

注意：注解配置我们不需要 userMapper.xml 文件了