基于注解入门实例

Posted 2020-12-03 zhoanghua

1、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;       }

　　

 

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

　　

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

　　

 

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 3、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