Mapper接口开发方法只需要程序员编写Mapper接口(相当于Dao接口),由Mybatis框架根据接口定义创建接口的动态代理对象,代理对象的方法体同Dao接口实现类方法。
Mapper接口开发需要遵循以下规范:
1、 Mapper.xml文件中的namespace与mapper接口的类路径相同;
2、 Mapper接口方法名和Mapper.xml中定义的每个statement的id相同 ;
3、 Mapper接口方法的输入参数类型和mapper.xml中定义的每个sql 的parameterType的类型相同;
4、 Mapper接口方法的输出参数类型和mapper.xml中定义的每个sql的resultType的类型相同.
UserMapper接口如下:
package com.sea.crm.mapper;
import java.util.List;
import com.sea.crm.pojo.User;
public interface UserMapper {
public int save(User user);
public User queryById(int id);
public List<User> queryByName(String name);
public List<User> queryAll();
public int update(User user);
public int delete(int id);
}
UserMapper.xml如下:
<?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">
<!-- namespace:命名空间,用于隔离sql>
<mapper namespace="com.sea.crm.mapper.UserMapper">
<!-- 添加用户 -->
<insert id="save" parameterType="com.sea.crm.pojo.User">
insert into user(userName,birthday,sex,address)
values(#{username},#{birthday},#{sex},#{address})
</insert>
<!-- 根据ID查询用户 -->
<select id="queryById" parameterType="int" resultType="com.sea.crm.pojo.User">
select * from user where id = #{id}
</select>
<!-- 根据名称模糊查询 -->
<select id="queryByName" parameterType="string" resultType="com.sea.crm.pojo.User">
select * from user where username like '%${value}%'
</select>
<!-- 查询全部 -->
<select id="queryAll" resultType="com.sea.crm.pojo.User">
select * from user
</select>
<!-- 修改用户信息 -->
<update id="update" parameterType="com.sea.crm.pojo.User">
update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id}
</update>
<!-- 根据ID删除用户 -->
<delete id="delete" parameterType="int">
delete from user where id = #{id}
</delete>
</mapper>
SqlMapConfig.xml如下:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 和spring整合后 environments配置将废除 -->
<environments default="development">
<environment id="development">
<!-- 使用jdbc事务管理 -->
<transactionManager type="JDBC" />
<!-- 数据库连接池 -->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url"
value="jdbc:mysql://localhost:3306/seamybatis?characterEncoding=utf-8" />
<property name="username" value="******" />
<property name="password" value="******" />
</dataSource>
</environment>
</environments>
<!-- 注册映射文件 -->
<!-- 将映射文件配置到mybatis的配置文件中 -->
<mappers>
<mapper resource="sqlmap/UserMapper.xml"/>
</mappers>
</configuration>
单元测试这里就写一个添加用户了:
package com.sea.crm.test;
import java.io.InputStream;
import java.util.Date;
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.sea.crm.mapper.UserMapper;
import com.sea.crm.pojo.User;
/**
* @author Sea You
*
* 2018年10月30日上午1:07:06
*/
public class MyBatisTest {
SqlSessionFactory factory = null;
private UserMapper userMapper=null;
@Before
public void testInit() {
// 1. 创建SqlSessionFactoryBuilder对象
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
// 2. 加载SqlMapConfig.xml配置文件
InputStream in = MyBatisTest.class.getResourceAsStream("/SqlMapConfig.xml");
// 3. 创建SqlSessionFactory对象
factory = builder.build(in);
}
@Test
public void testSave() {
User user = new User();
user.setUsername("尤海");
user.setBirthday(new Date());
user.setSex(1);
user.setAddress("江苏无锡");
SqlSession session = factory.openSession();
//通过动态代理实现接口对象
userMapper = session.getMapper(UserMapper.class);
userMapper.save(user);
session.commit();
session.close();
}
}
添加测试成功: