resultMap：适合使用返回值是自己定义实体类的情况

resultType：适合使用返回值得数据类型是非自己定义的，即jdk的提供的类型

resultMap ： 

type：映射实体类的数据类型

id：resultMap的唯一标识

column:库表的字段名

property：实体类里的属性名

配置映射文件：

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:当前库表映射文件的命名空间，唯一的不能反复 --> <mapper namespace="com.hao947.sql.mapper.PersonMapper"> <!-- type:映射实体类的数据类型 id：resultMap的唯一标识 --> <resultMap type="person" id="BaseResultMap"> <!-- column:库表的字段名 property:实体类里的属性名 --> <id column="person_id" property="personId" /> <result column="name" property="name" /> <result column="gender" property="gender" /> <result column="person_addr" property="personAddr" /> <result column="birthday" property="birthday" /> </resultMap> <!--id:当前sql的唯一标识 parameterType：输入參数的数据类型 resultType：返回值的数据类型 #{}:用来接受參数的。假设是传递一个參数#{id}内容随意，假设是多个參数就有一定的规则,採用的是预编译的形式select * from person p where p.id = ? ，安全性非常高 --> <!-- sql语句返回值类型使用resultMap --> <select id="selectPersonById" parameterType="java.lang.Integer" resultMap="BaseResultMap"> select * from person p where p.person_id = #{id} </select> <!-- resultMap:适合使用返回值是自己定义实体类的情况 resultType：适合使用返回值的数据类型是非自己定义的，即jdk的提供的类型 --> <select id="selectPersonCount" resultType="java.lang.Integer"> select count(*) from person </select> <select id="selectPersonByIdWithMap" parameterType="java.lang.Integer" resultType="java.util.Map"> select * from person p where p.person_id= #{id} </select> </mapper>

实体类Person.java

package com.hao947.model;import java.util.Date;public class Person {	private Integer personId;	private String name;	private Integer gender;	private String personAddr;	private Date birthday;	@Override	public String toString() {		return "Person [personId=" + personId + ", name=" + name + ", gender="				+ gender + ", personAddr=" + personAddr + ", birthday="				+ birthday + "]";	}}

測试类

public class PersonTest {	SqlSessionFactory sqlSessionFactory;	@Before	public void setUp() throws Exception {		// 读取资源流		InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");		// 初始化session工厂		sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);	}		@Test	public void selectPersonById() {		// 创建一个sqlsession		SqlSession session = sqlSessionFactory.openSession();		try {			Person p = session.selectOne(					"com.hao947.sql.mapper.PersonMapper.selectPersonById", 1);			System.out.println(p);		} finally {			session.close();		}	}	@Test	public void selectPersonCount() {		// 创建一个sqlsession		SqlSession session = sqlSessionFactory.openSession();		try {			Integer p = session.selectOne(					"com.hao947.sql.mapper.PersonMapper.selectPersonCount");			System.out.println(p);		} finally {			session.close();		}	}	@Test	public void selectPersonByIdWithMap() {		// 创建一个sqlsession		SqlSession session = sqlSessionFactory.openSession();		try {			Map
     
       map = session.selectOne(					"com.hao947.sql.mapper.PersonMapper.selectPersonByIdWithMap",1);			System.out.println(map);		} finally {			session.close();		}	}}