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分页配置

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stivepeim edited this page Dec 31, 2020 · 1 revision

分页配置

配置代码 此处不需要改动

package com.common;

import com.constants.Constants;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

@Data
public class PageParamRequest {

    @ApiModelProperty(value = "页码", example= Constants.DEFAULT_PAGE + "")
    private int page = Constants.DEFAULT_PAGE;

    @ApiModelProperty(value = "每页数量", example = Constants.DEFAULT_LIMIT + "")
    private int limit = Constants.DEFAULT_LIMIT;

}

配置常量

package com.constants;
    public class Constants {
        //默认分页页码
        public static final int DEFAULT_PAGE = 1;
        
        //默认分页每页数量
        public static final int DEFAULT_LIMIT = 20;

        //此处省略无数其余常量配置
}
  1. 如果想修改默认分页数值，请修改 DEFAULT_LIMIT 的值即可，这块会在前端不传递分页参数的时候起作用，或者自己new 分页参数类的时候起作用。
  2. 分页参数的最终值以前端传递为准
  3. 需要分页的时候在 *ServiceImpl文件的具体方法里，执行sql之前加一行代码
PageHelper.startPage(pageParamRequest.getPage(), pageParamRequest.getLimit());
  1. 如果最终方法返回的类和当前分页的时候映射的类不相同，例如当前业务是 class a，需要返回 class b，那么需要处理下数据。下文看文章这块如何处理
/**
* 文章列表
* @param request ArticleSearchRequest 请求参数
* @param pageParamRequest 分页类参数
* @author Mr.Zhang
* @since 2020-04-18
* @return List<Article>
*/
@Override
public PageInfo<ArticleVo> getList(ArticleSearchRequest request, PageParamRequest pageParamRequest) {

    //需要做赋值操作
    Page<Article> articlePage = PageHelper.startPage(pageParamRequest.getPage(), pageParamRequest.getLimit());

    LambdaQueryWrapper<Article> lambdaQueryWrapper = new LambdaQueryWrapper<>();

    if(StringUtils.isNotBlank(request.getCid())){
        lambdaQueryWrapper.eq(Article::getCid, request.getCid());
    }

    if(!StringUtils.isBlank(request.getKeywords())){
        lambdaQueryWrapper.and(i -> i.or().like(Article::getTitle, request.getKeywords())
                .or().like(Article::getAuthor, request.getKeywords())
                .or().like(Article::getSynopsis, request.getKeywords())
                .or().like(Article::getShareTitle, request.getKeywords())
                .or().like(Article::getShareSynopsis, request.getKeywords()));
    }

    if(request.getIsBanner() != null){
        lambdaQueryWrapper.eq(Article::getIsBanner, request.getIsBanner());
    }

    if(request.getIsHot() != null){
        lambdaQueryWrapper.eq(Article::getIsHot, request.getIsHot());
    }

    if(request.getHide() != null){
        lambdaQueryWrapper.eq(Article::getHide, request.getHide());
    }

    if(request.getStatus() != null){
        lambdaQueryWrapper.eq(Article::getStatus, request.getStatus());
    }

    if(null != request.getIsHaveMediaId()){
        lambdaQueryWrapper.isNotNull(Article::getMediaId).ne(Article::getMediaId, "");
    }


    lambdaQueryWrapper.orderByDesc(Article::getSort).orderByDesc(Article::getVisit).orderByDesc(Article::getCreateTime);
    List<Article> articleList = dao.selectList(lambdaQueryWrapper);

    ArrayList<ArticleVo> articleVoArrayList = new ArrayList<>();
    if(articleList.size() < 1){
        return CommonPage.copyPageInfo(articlePage, articleVoArrayList);
    }

    for (Article article : articleList) {
        ArticleVo articleVo = new ArticleVo();
        BeanUtils.copyProperties(article, articleVo);
        if(!StringUtils.isBlank(article.getImageInput()) ){
            articleVo.setImageInput(CrmebUtil.jsonToListString(article.getImageInput()));
            articleVo.setImageInputs(article.getImageInput());
        }
        articleVoArrayList.add(articleVo);
    }
    
    //需要通过复制转化分页类指定的对象
    return CommonPage.copyPageInfo(articlePage, articleVoArrayList);  
}

分页操作类

package com.common;
import com.constants.Constants;
import lombok.Data;
import org.springframework.beans.BeanUtils;
import org.springframework.data.domain.Page;
import com.github.pagehelper.PageInfo;


import java.util.ArrayList;
import java.util.List;

@Data
public class CommonPage<T> {
    private Integer page = Constants.DEFAULT_PAGE;
    private Integer limit = Constants.DEFAULT_LIMIT;
    private Integer totalPage = 0;
    private Long total = 0L ;
    private List<T> list = new ArrayList<>();


    /**
     * 将PageHelper分页后的list转为分页信息
     */
    public static <T> CommonPage<T> restPage(List<T> list) {
        CommonPage<T> result = new CommonPage<T>();
        PageInfo<T> pageInfo = new PageInfo<T>(list);
        result.setTotalPage(pageInfo.getPages());
        result.setPage(pageInfo.getPageNum());
        result.setLimit(pageInfo.getPageSize());
        result.setTotal(pageInfo.getTotal());
        result.setList(pageInfo.getList());
        return result;
    }

    /**
     * 将SpringData分页后的list转为分页信息
     */
    public static <T> CommonPage<T> restPage(Page<T> pageInfo) {
        CommonPage<T> result = new CommonPage<T>();
        result.setTotalPage(pageInfo.getTotalPages());
        result.setPage(pageInfo.getNumber());
        result.setLimit(pageInfo.getSize());
        result.setTotal(pageInfo.getTotalElements());
        result.setList(pageInfo.getContent());
        return result;
    }

    /**
     * 将PageHelper分页后的 PageInfo 转为分页信息
     */
    public static <T> CommonPage<T> restPage(PageInfo<T> pageInfo) {
        CommonPage<T> result = new CommonPage<T>();
        result.setTotalPage(pageInfo.getPages());
        result.setPage(pageInfo.getPageNum());
        result.setLimit(pageInfo.getPageSize());
        result.setTotal(pageInfo.getTotal());
        result.setList(pageInfo.getList());
        return result;
    }

    /**
     * 对象A复制对象B的分页信息 //TODO 多次数据查询导致分页数据异常解决办法
     */
    public static <T> PageInfo<T> copyPageInfo(com.github.pagehelper.Page originPageInfo, List<T> list) {
        PageInfo<T> pageInfo = new PageInfo<>(list);
        BeanUtils.copyProperties(originPageInfo, pageInfo, "list");
        return pageInfo;
    }
}

在控制器里需要用下面代码来接受分页类的信息作为数据输出

CommonPage.restPage(articleService.getList(request, pageParamRequest))

对外输出JSON下面自动封装

/**
 * 分页显示文章管理表
 * @param request ArticleSearchRequest 搜索条件
 * @param pageParamRequest 分页参数
 * @author Mr.Zhang
 * @since 2020-04-18
 */
@ApiOperation(value = "分页列表")
@RequestMapping(value = "/list", method = RequestMethod.GET)
@ApiImplicitParam(name="keywords", value="搜索关键字")
public CommonResult<CommonPage<ArticleVo>> getList(@Validated ArticleSearchRequest request,
                                                   @Validated PageParamRequest pageParamRequest){
    return CommonResult.success(CommonPage.restPage(articleService.getList(request, pageParamRequest)));
}
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