使用MyBatis进行数据库映射的方式

<dependency>
 <groupId>org.mybatis</groupId>
 <artifactId>mybatis</artifactId>
 <version>3.4.5</version>
</dependency>

<?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"></properties>
 <environments default="my-config">
   <environment id="my-config">
    <transactionManager type="JDBC" />
    <dataSource type="POOLED">
     <property name="driver" value="${driver}"></property>
     <property name="url" value="${url}"></property>
     <property name="username" value="${user}"></property>
     <property name="password" value="${pwd}"></property>
    </dataSource>
   </environment>
 </environments>
 <mappers>
  <mapper resource="mapping.xml" />
 </mappers>
</configuration>

url=jdbc:oracle:thin:@xxx.xxx.xxx.xx:1521/orcl
user=xxx
pwd=xxx
driver=oracle.jdbc.driver.OracleDriver

<?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="user">
  <select id="es_temp" fetchSize="10" resultType="java.util.LinkedHashMap">
   select ENTNAME,UNISCID,INDUSTRY,REGION,OPSTATE,ESTYEAR,SCALE from xxx where rownum <![CDATA[<=]]> 20
  </select>
</mapper>

import java.io.Reader;
import java.util.*;
import com.alibaba.fastjson.*;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.*;
public class Demo {
  public static SqlSessionFactory sessionFactory;
  public static void main(String[] args) {
    try {
      Reader reader = Resources.getResourceAsReader("config.xml");
      sessionFactory = new SqlSessionFactoryBuilder().build(reader);
      SqlSession session = sessionFactory.openSession();
      List<LinkedHashMap<?,?>> result = session.selectList("user.es_temp");
      String json_str = JSON.toJSONString(result);
      System.out.println(json_str);
      session.close();
    } catch (Exception e){
      e.printStackTrace();
    }
  }
}

[
  {
    "ENTNAME":"深圳市蓝海汇装饰设计工程有限公司",
    "UNISCID":"91440300359236108Q",
    "INDUSTRY":"批发和零售业",
    "REGION":"深圳",
    "OPSTATE":"存续（在营、开业、在册）",
    "ESTYEAR":"3年以下",
    "SCALE":"小微企业"
  },
  {
    "ENTNAME":"暴风雨（深圳）电子商务有限公司",
    "UNISCID":"91440300MA5DF887XE",
    "INDUSTRY":"批发和零售业",
    "REGION":"深圳",
    "OPSTATE":"存续（在营、开业、在册）",
    "ESTYEAR":"3年以下",
    "SCALE":"小微企业"
  },
  ...
]