MybatisPlus

1. MybatisPlus

mybatis-plus的pom依赖(详细见官网)

        <!--mybatis-plus-->
        <!--mybatis-plus与spring-boot的集成包，不用再导入mybatis和mybatis-spring的包-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
        </dependency>
        <!--代码生成器-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
        </dependency>

2. BUG解决

1.查询部分字段, 但是返回所有字段,未查询字段显示为null

1. 使用Mybatis-plus做自定义SQL查询部分字段时,查询出了表中所有的字段,sql语句中未提到的字段显示为空的问题:

   实体类 :

   package com.workorder.work_order.pojo;
   
   import com.baomidou.mybatisplus.annotation.TableName;
   import com.baomidou.mybatisplus.annotation.IdType;
   import com.baomidou.mybatisplus.annotation.TableId;
   import java.time.LocalDateTime;
   import com.baomidou.mybatisplus.annotation.TableField;
   import java.io.Serializable;
   
   import lombok.AllArgsConstructor;
   import lombok.Data;
   import lombok.EqualsAndHashCode;
   import lombok.NoArgsConstructor;
   import lombok.experimental.Accessors;
   @Data
   @AllArgsConstructor
   @NoArgsConstructor
   @EqualsAndHashCode(callSuper = false)
   @Accessors(chain = true)
   @TableName("work_order_classification")
   public class WorkOrderClassification implements Serializable {
   
       private static final long serialVersionUID = 1L;
   
       @TableId(value = "id", type = IdType.AUTO)
       private Long id;
   
       /**
        * 工单分类信息
        */
       @TableField("name")
       private String name;
       /**
        * 工单关联分类信息
        */
       @TableField("node_id")
       private String nodeId;
   
       /**
        * 创建时间
        */
       @TableField("create_time")
       private LocalDateTime createTime;
   
       /**
        * 更新时间
        */
       @TableField("update_time")
       private LocalDateTime updateTime;
   }
   
   

   Mapper接口:

   package com.workorder.work_order.mapper;
   
   import com.baomidou.mybatisplus.core.conditions.Wrapper;
   import com.baomidou.mybatisplus.core.toolkit.Constants;
   import com.devloper.joker.mybatis.plus.query.core.QuerySupport;
   import com.workorder.work_order.pojo.WorkOrderClassification;
   import com.baomidou.mybatisplus.core.mapper.BaseMapper;
   import org.apache.ibatis.annotations.Param;
   import org.apache.ibatis.annotations.ResultMap;
   import org.apache.ibatis.annotations.Select;
   
   import java.util.List;
   import java.util.Map;
   
   /**
    *
    * @author lw
    * @since 2019-06-27
    */
   public interface WorkOrderClassificationMapper extends BaseMapper<WorkOrderClassification> {
   
       /**
        * 获取数据列表
        * @param
        * @return
        */
   
       String  getOrderClassification= "SELECT ID,NAME ,NODE_ID FROM work_order_classification";
   
       @ResultMap("ClassificationResultMap")
       @Select(getOrderClassification)
       @QuerySupport
       List<Map<String,Object>> getOrderClassification();
   
   }
   
   

   ps: 接口中定义为如下,会返回实体类所有的字段属性,

   ​ 而sql中未查询的字段,会默认为实体类中对应的字段赋值为null .

   List<WorkOrderClassification>getOrderClassification();
   

   ​ 应该设置以下此接口用map接收得到的sql查询数据

    List<Map<String,Object>> getOrderClassification();
   

   ​ 对应的在mapper的配置文件WorkOrderClassificationmapper.xml中 , 配置查询的返回值类型

   <?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.workorder.work_order.mapper.WorkOrderClassificationMapper">
   
       <!-- 通用查询映射结果 -->
       <resultMap id="ClassificationResult" type="com.workorder.work_order.pojo.WorkOrderClassification">
           <id column="id" property="id"/>
           <result column="node_id" property="nodeId"/>
           <result column="name" property="name"/>
           <result column="create_time" property="createTime"/>
          	<result column="update_time" property="updateTime"/>
       </resultMap>
       
       <resultMap id="ClassificationResultMap" type="java.util.Map">
           <id column="id" property="id"/>
           <result column="node_id" property="nodeId"/>
           <result column="name" property="name"/>
   
       </resultMap>
   
   </mapper>
   
   

   最后在业务层写具体代码即可 , 定义一个 List<Map<String,Object>>对象接收返回的SQL对象

   public Result getOrderClassification() {
    List<Map<String,Object>> list=workOrderClassificationMapper.getOrderClassification();
       if(list!=null){
           return Result.ok(list);
       }else{
           return Result.error(500,"查找失败");
       }
   
   }