Mybatis中的resultType和resultMap查询操作实例详解

resulttype和resultmap只能有一个成立，resulttype是直接表示返回类型的，而resultmap则是对外部resultmap的引用，resultmap解决复杂查询是的映射问题。比如：列名和对象属性名不一致时可以使用resultmap来配置；还有查询的对象中包含其他的对象等。

mybatisconfig.xml

<?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>
<!--定义别名 注意typealiases一定要在environments之前-->
<typealiases>
<typealias type="jike.book.pojo.jikeuser" alias="jikeuser"/>
</typealiases>
<environments default="development">
<environment id="development">
<transactionmanager type="jdbc">
</transactionmanager>
<datasource type="pooled">
<property name="driver" value="com.mysql.jdbc.driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/jikebook"/>
<property name="username" value="root"/>
<property name="password" value="*****"/>
</datasource>
</environment>
</environments>
<mappers>
<mapper resource="jike/book/map/jikeuser.xml"/>
<mapper class="jike.book.impl.interfacejikeusermap"/>
</mappers>
</configuration>

jikeuser.xml

<?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="/">
<resultmap id="jikeusermap" type="jikeuser">
<id property="id" column="id"/>
<result property="username" column="username"/>
<result property="password" column="password"/>
</resultmap>
<select id="selectusermap" resultmap="jikeusermap">
select * from jikeuser;
</select>
<select id="selectuserlist" resulttype="jikeuser" parametertype="jikeuser">
select * from jikebook.jikeuser;
</select>
</mapper>

testselect.java

package jike.book.test;
import jike.book.pojo.jikeuser;
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 java.io.ioexception;
import java.io.reader;
import java.util.list;
/**
* datetime: 2016/9/5 21:45
* 功能：
* 思路：
*/
public class testselect {
public static void main(string[] args) {
// 资源路径
string resource="jike/book/map/mybatisconfig.xml";
reader reader=null;
sqlsession session;
try {
reader= resources.getresourceasreader(resource);
} catch ( ioexception e ) {
e.printstacktrace();
}
sqlsessionfactory sqlmapper=new sqlsessionfactorybuilder().build(reader);
session=sqlmapper.opensession();
list<jikeuser> list=session.selectlist("selectusermap");
// list<jikeuser> list=session.selectlist("selectuserlist");
for(jikeuser jikeuser:list){
system.out.println(jikeuser.getusername());
}
session.close();
}
}

运行

list<jikeuser> list=session.selectlist("selectusermap");

或者

list<jikeuser> list=session.selectlist("selectuserlist");

结果都是一样的

以上所述是小编给大家介绍的mybatis中的resulttype和resultmap查询操作实例详解，希望对大家有所帮助