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mybatis学习之路(二)mapper代理开发方法-开发规范及实现
1.在mapper.xml中namespace等于mapper接口得地址
<?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">
<mapper namespace="com.jjt.ssm.mapper.TuserMapper">
<select id="findUserById" parameterType="int" resultType="com.jjt.ssm.pojo.Tuser">
SELECT * FROM tuser WHERE id=#{userid}
</select>
</mapper>
2.mapper.java接口中的方法名字和mapper.xml中的statement即(findUserById)一致
3.mapper.java接口中的方法输入参数类型和mapper.xml和statement的parameterType指定类型保持一致。
4.mapper.java接口中的返回类型和mapper.xml和statement的resultType指定类型保持一致。
import com.jjt.ssm.pojo.Tuser;
public interface TuserMapper {
public Tuser findUserById(int userid) throws Exception;
}
sqlMapConfig.xml配置
<?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整合后这个 environments 移除-->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<!-- 配置数据库连接信息 -->
<dataSource type="POOLED">
<!-- value属性值引用db.properties配置文件中配置的值 -->
<property name="driver" value="http://www.mamicode.com/com.mysql.jdbc.Driver" />
<property name="url" value="http://www.mamicode.com/jdbc:mysql://127.0.0.1:3306/jiajitao?useUnicode=true&characterEncoding=UTF-8" />
<property name="username" value="http://www.mamicode.com/root" />
<property name="password" value="http://www.mamicode.com/root" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- <mapper resource="sqlmap/Tuser.xml"/> -->
<mapper resource="mapper/TuserMapper.xml"/>
</mappers>
</configuration>
测试类
import java.io.InputStream;
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 com.jjt.ssm.pojo.Tuser;
public class TuserMapperTest {
SqlSessionFactory sqlSessionFactory;@Before
public void setUp() throws Exception {
String resource = "sqlMapConfig.xml";
// 配置文件读取
InputStream inputStream = Resources.getResourceAsStream(resource);sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}@Test
public void testFindUserById() throws Exception {
SqlSession sqlSession = sqlSessionFactory.openSession();
TuserMapper userMapper = sqlSession.getMapper(TuserMapper.class);
Tuser user = userMapper.findUserById(1);
System.out.println(user.getUsername());}
}
mybatis学习之路(二)mapper代理开发方法-开发规范及实现