mybatis中resulthandler的用法

目录

• resulthandler的用法
• 创建实体类
• sql，返回值类型要写
• Mapper，返回值必须是void
• Test
• ResultHandler(传入map返回map)
• 测试代码
• 实现
• xml

resulthandler的用法

ResultHandler，顾名思义，对返回的结果进行处理，最终得到自己想要的数据格式或类型。也就是说，可以自定义返回类型。下面通过一个例子讲解它的使用方法：

创建实体类

package com.ccb.demossm.entity;
import com.ccb.demossm.annotation.MyAnnotation;
import org.springframework.stereotype.Component;
@Component
public class Users {
    //用户ID
    private String userId;
    //用户名
    private String userName;
    //用户密码
    private String userPwd;
    //用户性别
    public String sex;
    //备注
    protected String mark;
    public String getMark() {
        return mark;
    }
    public void setMark(String mark) {
        this.mark = mark;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getUserId() {
        return userId;
    }
    public void setUserId(String userId) {
        this.userId = userId;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getUserPwd() {
        return userPwd;
    }
    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }
    public Users() {
    }
    public Users(String userId) {
        this.userId = userId;
    }
}

sql，返回值类型要写

    <select id="getUserResult" resultType="com.ccb.demossm.entity.Users">
         select u.userId,u.userName, u.userPwd from users u
    </select>

Mapper，返回值必须是void

void getUserResult(ResultHandler<Users> resultHandler);package com.ccb.demossm.mapper;
import com.ccb.demossm.entity.Users;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.session.ResultHandler;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Repository;
import java.util.List;
import java.util.Map;
@Repository
@SpringBootApplication
public interface UsersMapper {
    void getUserResult(ResultHandler<Users> resultHandler);
}

Test

package com.ccb.demossm;
import com.ccb.demossm.entity.Users;
import com.ccb.demossm.mapper.UsersMapper;
import org.apache.ibatis.session.ResultContext;
import org.apache.ibatis.session.ResultHandler;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
@SpringBootTest
@RunWith(SpringRunner.class)
public class TestResultHandle {
    @Autowired
   private UsersMapper usersMapper;
    @Test
    public void test() {
        usersMapper.getUserResult(new ResultHandler<Users>() {
            @Override
            public void handleResult(ResultContext<? extends Users> resultContext) {
                Users resultObject = resultContext.getResultObject();
                String userId = resultObject.getUserId();
                //写数据处理业务
                System.out.println(userId);
            }
        });
    }
}

ResultHandler(传入map返回map)

测试代码

package com.xwhbshweb.service;
import java.util.HashMap;
import java.util.Map;
import org.apache.ibatis.session.ResultContext;
import org.apache.ibatis.session.ResultHandler;
public interface OrdersService {
    /**
     * 返回某日订单成交数及当日成交总金额 day 的格式为 2018/01/30
     *
     * 若 day 为 null 则返回总成交订单及总成交金额
     *
     * @param id
     *            商户号
     * @param day
     * @return
     */
    public Map<String, String> getOrderCountTotal(String id, String day);
    /**
     * 处理 select 结果
     *
     * @author Administrator
     *
     */
    class OrdersResultHandler implements ResultHandler {
        private final Map<String, String> mappedResults = new HashMap<String, String>();
        @Override
        public void handleResult(ResultContext resultContext) {
            Map map = (Map) resultContext.getResultObject();
            if (map.get("count") instanceof Long) {
                System.out.println("count Long ");
                if (null == String.valueOf((Long) map.get("count"))
                        || String.valueOf((Long) map.get("count")).equals("")) {
                    mappedResults.put("count", "0");
                } else {
                    mappedResults.put("count", String.valueOf((Long) map.get("count")));
                }
            }

            if (map.get("total") instanceof Double) {
                System.out.println("total Long ");
                String total = String.valueOf((Double) map.get("total")).split("\\.")[0];
                if (total.equals("0")) {
                    mappedResults.put("total", "0");
                }else {
                    float yuan = Float.valueOf(total) / 1000;
                    mappedResults.put("total", String.valueOf(yuan));
                }
            }
        }
        public Map getMappedResults() {
            return mappedResults;
        }
    }
}

实现

package com.xwhbshweb.service.imp;
import java.util.HashMap;
import java.util.Map;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.stereotype.Service;
import com.xwhbshweb.config.MybatisSqlSessionFactory;
import com.xwhbshweb.service.OrdersService;
@Service
public class OrdersServiceI implements OrdersService {
    private SqlSessionFactory sqlSessionFactory = MybatisSqlSessionFactory.getOne();
    @Override
    public Map<String, String> getOrderCountTotal(String id,String day) {
        SqlSession session = sqlSessionFactory.openSession(true);
        Map<String, String> params = new HashMap<String, String>();
        params.put("id", id);
        if (null == day) {
            params.put("day", "%");
        }else {
            params.put("day", day+"%");
        }
        OrdersService.OrdersResultHandler handler = new OrdersService.OrdersResultHandler();
        session.select("com.xwhbank.cn.config.mybatis.namespace.ordersMapper.selectDayOrderCountTotal", params, handler);
        session.close();
        Map<String,String> map =handler.getMappedResults();
        return map;
    }
}

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="com.xwhbank.cn.config.mybatis.namespace.ordersMapper">
  <select id="selectOne"  resultType="orders">
    select * from orders where the_super_id = #{id};
  </select>

   <select id="selectDayOrderCountTotal"  parameterType="java.util.Map" resultType="java.util.HashMap">
    select count(*) as count,SUM(money_to_tenant) as total from orders where the_super_id = #{id} and order_time like #{day} and state='2';
  </select>

 <insert id="insertOne" parameterType="orders">
      insert into orders (id,tenant_order_no,the_super_id,state,money_amount,cut,money_to_tenant,money_to_xwh,pay_way,good_info,asy_notify_url,sy_return_url,sign_,order_time,sharding_id) values ("next value for MYCATSEQ_order",#{tenant_order_no},#{the_super_id},#{state},#{money_amount},#{cut},#{money_to_tenant},#{money_to_xwh},#{pay_way},#{good_info},#{asy_notify_url},#{sy_return_url},#{sign_},#{order_time},#{sharding_id});
  </insert>

</mapper>

注意传入 map参数 及 传出map参数 的颜色对应

map传入值时 若是不同类型 将 map的值改为Object就好了

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。