mybatis 详解（三）------入门实例（基于注解）

1、创建MySQL数据库：mybatisDemo和表：user

2、建立一个Java工程，并导入相应的jar包，具体目录如下

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

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

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();
}
}