mybatis-plus使用问题小结

更新时间：2022年03月01日 11:37:19 作者：别动我的猫

这篇文章主要介绍了mybatis-plus使用问题汇总,本文通过实例代码给大家介绍的非常详细，对大家的学习或工作具有一定的参考借鉴价值，需要的朋友可以参考下

一、多表联合分页查询

1.多表联合查询结果集建议使用VO类，当然也可以使用resultMap

package com.cjhx.tzld.entity.vo;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.cjhx.tzld.entity.TContent;
import com.fasterxml.jackson.annotation.JsonFormat;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import org.springframework.format.annotation.DateTimeFormat;
import java.util.Date;
@Data
@ApiModel(value="TContentVo", description="内容池多表联合数据对象")
public class TContentVo extends TContent {
    @ApiModelProperty(value = "编号")
    private Integer cid;
    @ApiModelProperty(value = "内容标题")
    private String title;
    @ApiModelProperty(value = "作者Id")
    @TableField("authorId")
    private Integer authorId;
    @ApiModelProperty(value = "时间")
    @JsonFormat(pattern="yyyy-MM-dd HH:mm:ss",timezone = "GMT+8") //返回时间类型
    @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss") //接收时间类型
    private Date time;
    @ApiModelProperty(value = "内容")
    private String content;
    @ApiModelProperty(value = "作者姓名")
    private String author;
    @ApiModelProperty(value = "话题")
    private String topic;
    @ApiModelProperty(value = "模块编号")
    private int moduleNum;
    @ApiModelProperty(value = "模块")
    private String module;
    public TContentVo() {
    }
    public TContentVo(Integer cid, String title, Date time, String content, String author, String topic, int moduleNum) {
        this.cid = cid;
        this.title = title;
        this.time = time;
        this.content = content;
        this.author = author;
        this.topic = topic;
        this.moduleNum = moduleNum;
}

2.controller

package com.cjhx.tzld.controller;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.cjhx.tzld.common.Result;
import com.cjhx.tzld.entity.TContent;
import com.cjhx.tzld.entity.TContentRelationFund;
import com.cjhx.tzld.entity.TTopicPk;
import com.cjhx.tzld.entity.vo.TContentVo;
import com.cjhx.tzld.service.TContentService;
import io.swagger.annotations.*;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
import java.util.Date;
import java.util.List;
/**
 * @since 2022-02-28
 */
@RestController
@RequestMapping("/content")
@Api("内容池模块")
public class ContentController {
    @Resource
    private TContentService contentService;
    @ApiImplicitParams({
            @ApiImplicitParam(name = "cid",value = "cid",dataType = "int",defaultValue = "0",required = false),
            @ApiImplicitParam(name = "title",value = "标题",dataType = "String",defaultValue = "",required = false),
            @ApiImplicitParam(name = "author",value = "作者姓名",dataType = "String",defaultValue = "",required = false),
            @ApiImplicitParam(name = "time",value = "发布时间",dataType = "Date",defaultValue = "",required = false),
            @ApiImplicitParam(name = "content",value = "内容",dataType = "String",defaultValue = "",required = false),
            @ApiImplicitParam(name = "topic",value = "话题",dataType = "String",defaultValue = "",required = false),
            @ApiImplicitParam(name = "moduleNum",value = "投放模块 1热点速递 2基会直达",dataType = "int",defaultValue = "",required = false),
            @ApiImplicitParam(name = "pageIndex",value = "页码",dataType = "int",defaultValue = "1",required = false),
            @ApiImplicitParam(name = "pageSize",value = "每页数量",dataType = "int",defaultValue = "10",required = false)
    })
    @ApiResponses({
            @ApiResponse(code = 200,message = "OK",response = TContent.class)
    @ApiOperation(value="分页获取内容接口(Web端)", notes="支持多条件查询",httpMethod = "GET")
    @RequestMapping(value = "/getContentPage",method = RequestMethod.GET)
    public Result getContentPage(@RequestParam(defaultValue = "0",required = false) int cid,
                                 @RequestParam(defaultValue = "",required = false) String title,
                                 @RequestParam(defaultValue = "",required = false) String author,
                                 @RequestParam(required = false) Date time,
                                 @RequestParam(defaultValue = "",required = false) String content,
                                 @RequestParam(defaultValue = "",required = false) String topic,
                                 @RequestParam(defaultValue = "0",required = false) int moduleNum,
                                 @RequestParam(defaultValue = "1",required = false) int pageIndex,
                                 @RequestParam(defaultValue = "10",required = false)  int pageSize) throws Exception{
        try {
            IPage<TContentVo> byPage = contentService.findByPage(new Page<TContentVo>(pageIndex, pageSize),new TContentVo(cid, title, time, content, author,  topic, moduleNum));
            return Result.success(byPage);
        }catch (Exception e){
            return Result.serviceFail(e.getMessage());
        }
    }
}

3.service

package com.cjhx.tzld.service.impl;

import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.cjhx.tzld.common.PageUtil;
import com.cjhx.tzld.entity.TContent;
import com.cjhx.tzld.entity.vo.TContentVo;
import com.cjhx.tzld.mapper.TContentMapper;
import com.cjhx.tzld.service.TContentService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.Date;
/**
 * @since 2022-02-28
 */
@Service
public class TContentServiceImpl extends ServiceImpl<TContentMapper, TContent> implements TContentService {
    @Resource
    private TContentMapper tContentMapper;
    @Override
    public IPage<TContentVo> findByPage(Page<TContentVo> page, TContentVo contentVo) {
        return tContentMapper.findByPage(page,contentVo);
    }
}

4.mapper

package com.cjhx.tzld.mapper;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.cjhx.tzld.entity.TContent;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.cjhx.tzld.entity.vo.TContentVo;
import org.apache.ibatis.annotations.Param;
/**
 * @since 2022-02-28
 */
public interface TContentMapper extends BaseMapper<TContent> {
    IPage<TContentVo> findByPage(Page<TContentVo> page, @Param("contentVo") TContentVo contentVo);
}

5.mapper.xml，注意入参contentVo

<?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.cjhx.tzld.mapper.TContentMapper">

    <select id="findByPage" resultType="com.cjhx.tzld.entity.vo.TContentVo" parameterType="com.cjhx.tzld.entity.vo.TContentVo">
        SELECT t.`cid`,t.`authorId`,a.`name`,t.`title`,t.`time`,t.`content`,p.`topic`,h.`title` AS `module`
        FROM `t_content` t
        LEFT JOIN `t_author` a ON a.`aid`=t.`authorId`
        LEFT JOIN `t_topic_pk` p ON p.`cid` = t.`cid`
        LEFT JOIN `t_hot_express` h ON h.`cid` = t.`cid`
        UNION ALL
        SELECT t.`cid`,t.`authorId`,a.`name`,t.`title`,t.`time`,t.`content`,p.`topic`,f.`title` AS `module`
        LEFT JOIN `t_fund_point` f ON f.`cid` = t.`cid`
        <where>
            1=1
            <if test="contentVo.cid > 0"> and cid = #{contentVo.cid}</if>
            <if test="contentVo.title != null and contentVo.title != ''"> and t.title like concat('%', #{contentVo.title}, '%')</if>
            <if test="contentVo.author != null and contentVo.author != ''"> and a.author like concat('%', #{contentVo.author}, '%')</if>
            <if test="contentVo.time != null"> and t.time =${contentVo.time}</if>
            <if test="contentVo.content != null and contentVo.content != ''"> and t.content like concat('%', #{contentVo.content}, '%')</if>
            <if test="contentVo.topic != null and contentVo.topic != ''"> and p.topic like concat('%', #{contentVo.topic}, '%')</if>
            <if test="contentVo.moduleNum == 1"> and f.currentState = -1</if>
            <if test="contentVo.moduleNum == 2"> and h.currentState = -1</if>
        </where>
        order by time desc
    </select>
</mapper>

二、找不到mapper

首先排除@MapperScan("com.cjhx.tzld.mapper")已添加

1.首先配置文件扫描，mapper-locations:classpath:/com/cjhx/tzld/mapper/xml/*.xml

mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  mapper-locations: classpath:/com/cjhx/tzld/mapper/xml/*.xml

2.在pom.xml的<build>添加xml资源

<build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
        <resources>
            <!--引入mapper对应的xml文件-->
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
    </build>

到此这篇关于mybatis-plus使用问题汇总的文章就介绍到这了,更多相关mybatis-plus使用内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！

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