一个使用MyBatis将数据库表中的一列内容放到List的例子
我的电脑操作系统版本为Win7旗舰版（ServicePack1），Oracle版本为Oracle11g
程序使用的jar包有：mybatis-3.2.2.jar、ojdbc14-10.2.0.2.0.jar
本例中使用的配置文件mybatis-config.xml，可以参见我的另一篇Blog《一个简单的MyBatis连接Oracle数据库的例子》（http://my.oschina.net/Tsybius2014/blog/626206）
现在Oracle数据库中建立一个新表RANK_LIST并插入一些数据，SQL如下：
CREATE TABLE RANK_LIST ( ID NUMBER(12,0) PRIMARY KEY, COMPETITION VARCHAR2(20) NOT NULL, RANK NUMBER(5, 0) NOT NULL, NAME VARCHAR(20) NOT NULL, INPUT_DATE NUMBER(10,0) DEFAULT TO_NUMBER(TO_CHAR(sysdate,'yyyymmdd')), INPUT_TIME NUMBER(10,0) DEFAULT TO_NUMBER(TO_CHAR(sysdate,'hh24miss')) ); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (1, 'COMP1', 1, 'TSYBIUS'); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (2, 'COMP1', 2, 'GALATEA'); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (3, 'COMP1', 3, 'GAIUS'); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (4, 'COMP1', 4, 'JULIA'); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (5, 'COMP2', 1, 'TSYBIUS'); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (6, 'COMP2', 2, 'GAIUS'); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (7, 'COMP2', 3, 'MARCUS'); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (8, 'COMP3', 1, 'QUINTUS'); INSERT INTO RANK_LIST (ID, COMPETITION, RANK, NAME) VALUES (9, 'COMP3', 2, 'MARCUS'); COMMIT; /
这个表中，ID为主键，COMPETITION为赛事，RANK为选手在这项赛事中取得的名次，NAME为选手的姓名。从PL/SQL中看到的RANK_LIST表内容如下：
现在要将获得了名次的选手按字母顺序正序取出，main函数调用代码如下：
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
/**
* MyBatis使用测试
* @author Tsybius2014
* @date 2016年3月14日
* @time 下午10:55:12
* @remark
*
*/
public class MyBatisTest {
public static void main(String[] args) {
try {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession session = sqlSessionFactory.openSession();
try {
RankListMapper mapper = session.getMapper(RankListMapper.class);
List<String> productList = mapper.getWinnerList();
System.out.println(productList);
} finally {
session.close();
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
RankListMapper.java代码如下：
import java.util.List;
public interface RankListMapper {
/** 获取在RANK_LIST表中榜上有名者的列表 */
List<String> getWinnerList();
}
RankListMapper.xml代码如下：
<?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"> <mapper namespace="RankListMapper"> <select id="getWinnerList" resultType="java.lang.String" > SELECT NAME FROM RANK_LIST GROUP BY NAME ORDER BY NAME </select> </mapper>
上面的main函数，执行结果为：
[GAIUS, GALATEA, JULIA, MARCUS, QUINTUS, TSYBIUS]
END