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mybatis-plus多表分頁查詢最佳實(shí)現(xiàn)方法(非常簡(jiǎn)單)

更新時(shí)間：2023年08月19日 11:00:06 作者：?jiǎn)误泔L(fēng)

這篇文章主要給大家介紹了關(guān)于mybatis-plus多表分頁查詢最佳實(shí)現(xiàn)方法,文中介紹的方法非常簡(jiǎn)單,MyBatis-Plus中分頁查詢是比較方便的,這個(gè)功能在網(wǎng)站中也是非常常用的,這方面的知識(shí)點(diǎn)是必備的知識(shí)點(diǎn),需要的朋友可以參考下

1.簡(jiǎn)介

在Mybatis Plus 中，雖然IService 接口幫我們定義了很多常用的方法，但這些都是 T 對(duì)象有用，如果涉及到多表的查詢，還是需要自定義Vo 對(duì)象和自己編寫sql 語句，Mybatis Plus提供了一個(gè)Page 對(duì)象,查詢是需要設(shè)置其中的 size 字段和 current 字段的值。

mybatis-plus的單表分頁就不必多說了，那多表聯(lián)查的分頁該如何實(shí)現(xiàn)呢？其實(shí)也很簡(jiǎn)單，你只需要自己寫好關(guān)聯(lián)查詢的sql再結(jié)合mybatis-plus提供的分頁對(duì)象，就可以實(shí)現(xiàn)了。但是如何才能優(yōu)雅的將分頁參數(shù)和查詢條件提供給mybatis-plus呢？我選擇使用
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;這個(gè)對(duì)象來實(shí)現(xiàn)。直接繼承baomidou提供的類可以省去每次手動(dòng)再new對(duì)象，因?yàn)樵讷@取參數(shù)時(shí)就已經(jīng)自動(dòng)構(gòu)建了

2.實(shí)現(xiàn)

2.1版本

    <mybatis-plus.version>3.5.1</mybatis-plus.version>
    <connector.version>8.0.18</connector.version>

            <!--    ================mybatis-plus==================        -->
            <!--mybatis-plus 持久層-->
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>${mybatis-plus.version}</version>
            </dependency>
            <!-- mybatis plus 代碼生成器依賴 -->
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-generator</artifactId>
                <version>${mybatis-plus.version}</version>
            </dependency>
            <!--    ================mybatis-plus==================        -->
            <!--mysql-->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${connector.version}</version>
            </dependency>

2.2分頁插件

@MapperScan(“。。。”)這些基本配置我就不多說了

@Configuration
public class MPConfig {
    /**
     * 分頁插件
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        //樂觀鎖
        //interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        //分頁鎖
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

2.3 分頁參數(shù) 繼承自 Page

直接繼承baomidou提供的類可以省去每次手動(dòng)再new對(duì)象，因?yàn)樵讷@取參數(shù)時(shí)就已經(jīng)自動(dòng)構(gòu)建了

package com.dxf.common.utils;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import io.swagger.annotations.ApiModelProperty;
import io.swagger.annotations.ApiParam;
import springfox.documentation.annotations.ApiIgnore;
import java.util.List;
public class PageParam<T> extends Page<T> {
    /**
     * 查詢數(shù)據(jù)列表
     */
    @ApiParam(hidden = true)
    private List<T> records;
    /**
     * 總數(shù)
     */
    @ApiParam(hidden = true)
    private long total = 0;
    /**
     * 每頁顯示條數(shù)，默認(rèn) 10
     */
    @ApiParam(value = "每頁大小，默認(rèn)10",required = false, defaultValue = "10")
    private long size = 10;
    /**
     * 當(dāng)前頁
     */
    @ApiParam(value = "當(dāng)前頁，默認(rèn)1",required = false,defaultValue = "1")
    private long current = 1;
    /**
     * 是否進(jìn)行 count 查詢
     */
    @ApiParam(hidden = true)
    private boolean isSearchCount = true;
    @Override
    @ApiParam(hidden = true)
    public List<T> getRecords() {
        return this.records;
    }
    @Override
    public Page<T> setRecords(List<T> records) {
        this.records = records;
        return this;
    }
    @Override
    public long getTotal() {
        return this.total;
    }
    @Override
    public Page<T> setTotal(long total) {
        this.total = total;
        return this;
    }
    @ApiParam(hidden = true)
    public boolean getSearchCount() {
        if (total < 0) {
            return false;
        }
        return isSearchCount;
    }
    @Override
    @ApiParam(hidden = true)
    public boolean isSearchCount() {
        if (total < 0) {
            return false;
        }
        return isSearchCount;
    }
    @Override
    public Page<T> setSearchCount(boolean isSearchCount) {
        this.isSearchCount = isSearchCount;
        return this;
    }
    @Override
    public long getSize() {
        return this.size;
    }
    @Override
    public Page<T> setSize(long size) {
        this.size = size;
        return this;
    }
    @Override
    public long getCurrent() {
        return this.current;
    }
    @Override
    public Page<T> setCurrent(long current) {
        this.current = current;
        return this;
    }
}

2.4 實(shí)現(xiàn)的重點(diǎn)mapper

import org.apache.ibatis.annotations.Param;
public interface SysRoleMapper extends BaseMapper<SysRole> {
    IPage<SysRole> searchPage(PageParam<SysRole> pageParam, @Param("name") String name);
}

關(guān)聯(lián)的是角色表和用戶表

<?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.dxf.data.mapper.SysRoleMapper">
    <select id="searchPage" resultType="com.dxf.data.entity.SysRole">
        SELECT r.id,r.name,r.status,r.role_sort, a.name create_by ,r.create_time,r.update_time,r.remark
        FROM sys_role r left join sys_user a on r.create_by=a.id
        <where>
            <if test="name != null and name != ''">
                r.name like concat(#{name},'%')
            </if>
        </where>
        order by r.role_sort
    </select>
</mapper>

2.5 其他層就是傳下參數(shù)

@RestController
@RequestMapping("/admin/role")
@Api(tags  = "SysRoleControllr|角色控制器")
public class SysRoleController {
    @Autowired
    SysRoleService roleService;
    @GetMapping("/page")
    @ApiOperation("角色列表分頁查詢")
    public ResultJson page(PageParam<SysRole> pageParam,String likeKey) {
        IPage<SysRole> iPage = roleService.searchPage(pageParam,likeKey);
        Map<String, Object> map = new HashMap<>();
        map.put("rows",iPage.getRecords());
        map.put("total",iPage.getTotal());
        return ResultJson.ok().data(map);
    }
public interface SysRole
}
Service extends IService<SysRole> {
    /**
     * 分頁查詢角色
     */
    IPage<SysRole> searchPage(PageParam<SysRole> pageParam,String name);
}
@Service
public class SysRoleServiceImpl extends ServiceImpl<SysRoleMapper, SysRole> implements SysRoleService {
    @Override
    public IPage<SysRole> searchPage(PageParam<SysRole> pageParam,String name) {
        return baseMapper.searchPage(pageParam,name);
    }
}