MyBatis 7 输出参数为简单类型、对象类型、HashMap及resultMap使用

输出参数为简单类型、对象类型、HashMap及resultMap使用

学习于https://study.163.com/course/courseMain.htm?courseId=1005847005&_trace_c_p_k2_=82d8e4a53fbd48c5842d426aad41b6d2

项目结构

1.

CREATE TABLE empinfo (
eid INT (10) PRIMARY KEY,
name VARCHAR (20),
age INT(10),
sex VARCHAR(5)
);

2.

<?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>
	
	<properties resource="db.properties"/>
	
	<typeAliases>
		<!-- 单个定义别名 -->
		<!-- <typeAlias type="org.lanqiao.entity.Empinfo" alias="empinfo"/> -->
		<!-- 批量定义别名 -->
		<package name="org.lanqiao.entity"/>
	</typeAliases>

	<!--通过 environments的 default值和environments的id值来指定MyBatis运行时的数据库环境-->
	 <environments default="development">
		 <environment id="development">
			 <transactionManager type="JDBC"/>
			 <dataSource type="POOLED">
			 	<!--修改的第一处，配置数据库信息，根据自己的数据库修改-->
				 <property name="driver" value="${driver}"/>
				 <property name="url" value="${url}"/>
				 <property name="username" value="${username}"/>
				 <property name="password" value="${password}"/>
			 </dataSource>
	 	</environment>
	 </environments>
	 <mappers>
	 	<!--加载映射文件-->
	 	<mapper resource="org/lanqiao/mapper/empinfoMapper.xml"/><!--修改的第二处-->
	 </mappers>
</configuration>

3.

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/company
username=root
password=root

4.

package org.lanqiao.entity;
 
public class Empinfo {
	private int eid;
	private String name;
	private int age;
	private String sex;
	private String phone;
	
	//无参构造
	public Empinfo () {
	}
	//有参构造
	public Empinfo (int eid, String name, int age, String sex, String phone) {
		super();
		this.eid = eid;
		this.name = name;
		this.age = age;
		this.sex = sex;
		this.phone = phone;
	}
	
	/**
	 * @return the eid
	 */
	public int getEid() {
		return eid;
	}
	/**
	 * @param eid the eid to set
	 */
	public void setEid(int eid) {
		this.eid = eid;
	}
	/**
	 * @return the name
	 */
	public String getName() {
		return name;
	}
	/**
	 * @param name the name to set
	 */
	public void setName(String name) {
		this.name = name;
	}
	/**
	 * @return the age
	 */
	public int getAge() {
		return age;
	}
	/**
	 * @param age the age to set
	 */
	public void setAge(int age) {
		this.age = age;
	}
	/**
	 * @return the sex
	 */
	public String getSex() {
		return sex;
	}
	/**
	 * @param sex the sex to set
	 */
	public void setSex(String sex) {
		this.sex = sex;
	}
	/**
	 * @return the phone
	 */
	public String getPhone() {
		return phone;
	}
	/**
	 * @param phone the phone to set
	 */
	public void setPhone(String phone) {
		this.phone = phone;
	}
	
	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return eid+"-"+name+"-"+age+"-"+sex+"-"+phone ;
	}
 
}

5.

<?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="org.lanqiao.mapper.EmpinfoMapper">
	<!-- 查询Empinfo总数 -->
 	<select id="queryEmpinfoCount" resultType="int" >	
 	select count(*) from empinfo
 	</select>
 	<!-- （1）按eid查询Empinfo-->
 	<select id="queryEmpinfoByeid" resultType="empinfo" parameterType="int" >	
 	select * from empinfo where eid=${value}<!-- 但是eid也行，这是数据库不同的原因吗？ -->
 	</select>
 	<!-- （4）.查询所有Empinfo -->
 	<select id="queryAllEmpinfos" resultType="Empinfo">
 		select * from empinfo
 	</select>
 	<!-- 别名作为Map的key 1 -->
 	<select id="queryAllEmpinfoOutByHashMap" resultType="HashMap">
 		select eid "id",name "nm" from empinfo where eid=200812011
 	</select>
 	<!-- 别名作为Map的key 2-->
 	<select id="queryAllEmpinfosOutByHashMap" resultType="HashMap">
 		select eid "id",name "nm" from empinfo 
 	</select>	
</mapper>

6.

package org.lanqiao.mapper;


import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.lanqiao.entity.Empinfo;

public interface EmpinfoMapper {
	//查询Empinfo总数
	int queryEmpinfoCount();
	Empinfo queryEmpinfoByeid(int eid);
	List<Empinfo> queryAllEmpinfos();
	//别名作为Map的key，1个学生的多个属性
	HashMap<String,Object> queryAllEmpinfoOutByHashMap();
	//别名作为Map的key，多个学生的多个属性
	List<HashMap<String,Object>> queryAllEmpinfosOutByHashMap();
}

7.

package org.lanqiao.test;

import java.io.IOException;
import java.io.Reader;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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.lanqiao.entity.Empinfo;
import org.lanqiao.mapper.EmpinfoMapper;

public class TestEmpinfo {
	//查询Empinfo总数
	public static void queryEmpinfoCount() throws IOException {
		Reader reader = Resources.getResourceAsReader("empinfoConf.xml");
		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);		
		SqlSession session = sessionFactory.openSession();
		
		EmpinfoMapper empinfoMapper = session.getMapper(EmpinfoMapper.class);
		int count=empinfoMapper.queryEmpinfoCount();
		System.out.println(count);
		session.close();
	}
	//（1）按eid查询Empinfo
	public static void queryEmpinfoByeid() throws IOException {
		Reader reader = Resources.getResourceAsReader("empinfoConf.xml");
		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);		
		SqlSession session = sessionFactory.openSession();
		
		EmpinfoMapper empinfoMapper = session.getMapper(EmpinfoMapper.class);
		Empinfo empinfo=empinfoMapper.queryEmpinfoByeid(20170519);
		System.out.println(empinfo);
		session.close();
	}
	//（4）.查询所有Empinfo
	public static void queryAllEmpinfos() throws IOException {
		Reader reader = Resources.getResourceAsReader("empinfoConf.xml");
		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);		
		SqlSession session = sessionFactory.openSession();
		//String statement = "org.lanqiao.entity.empinfoMapper."+"queryAllEmpinfos";		
		//List<Empinfo> empinfos = session.selectList(statement);
		EmpinfoMapper empinfoMapper = session.getMapper(EmpinfoMapper.class);
		List<Empinfo> empinfos=empinfoMapper.queryAllEmpinfos();
		System.out.println(empinfos);
		session.close();
	}
	//查询Empinfo，结果为Map类型
	public static void queryAllEmpinfoOutByHashMap() throws IOException {
		Reader reader = Resources.getResourceAsReader("empinfoConf.xml");
		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);		
		SqlSession session = sessionFactory.openSession();
		
		EmpinfoMapper empinfoMapper = session.getMapper(EmpinfoMapper.class);
		HashMap<String,Object> empinfoMap=empinfoMapper.queryAllEmpinfoOutByHashMap();
		System.out.println(empinfoMap);
		session.close();
	}
	//查询Empinfo，结果为Map类型
	public static void queryAllEmpinfosOutByHashMap() throws IOException {
		Reader reader = Resources.getResourceAsReader("empinfoConf.xml");
		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);		
		SqlSession session = sessionFactory.openSession();
		
		EmpinfoMapper empinfoMapper = session.getMapper(EmpinfoMapper.class);
		List<HashMap<String,Object>> empinfoMap=empinfoMapper.queryAllEmpinfosOutByHashMap();
		System.out.println(empinfoMap);
		session.close();
	}

	public static void main(String[] args) throws IOException {
		
		//queryEmpinfoCount();//查询Empinfo总数
		//queryEmpinfoByeid();
		//queryAllEmpinfos();
		//queryAllEmpinfoOutByHashMap();
		queryAllEmpinfosOutByHashMap();
	}
}