分页工具类

红太狼 2021-09-28 12:06 338阅读 0赞

package com.sms.tenantexamineserver.util;
    
    import org.apache.commons.lang3.StringUtils;
    
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.List;
    
    /**
     * @ClassName PageUtil
     * @Description TODO
     **/
    public class PageUtil {
        /**
         * 将数组分页，返回请求的页码的内容
         * @return java.lang.String[]
         **/
    //    public static String[] getPageList(String[] all,int pageNo,int pageSize){
    //        if(all == null || all.length <= 0){
    //            return null;
    //        }
    //        int length = all.length;
    //        //分页处理
    //        PageBean pageBean = new PageBean(pageSize,pageNo,length);
    //        int page = pageBean.getPageNo();
    //        int startIndex = (page -1) * pageSize;
    //        int endIndex = page * pageSize > length ? length : page * pageSize;
    //
    //        return Arrays.copyOfRange(all,startIndex,endIndex);
    //    }
    
        /**
         * 将数组分页，返回请求的页码的内容
         * @return java.lang.String[]
         **/
        public static Object[] getPageArray(Object[] all,int pageNo,int pageSize){
            if(all == null || all.length <= 0){
                return null;
            }
            int length = all.length;
            //分页处理
            PageBean pageBean = new PageBean(pageSize,pageNo,length);
            int page = pageBean.getPageNo();
            int startIndex = (page -1) * pageSize;
            int endIndex = page * pageSize > length ? length : page * pageSize;
    
            return Arrays.copyOfRange(all,startIndex,endIndex);
        }
    
        /**
         *  pageNo 页码
         *  pageSize 每页数量
         */
        public static <T> List<T> getPageList(List<T> all,int pageNo,int pageSize){
            if(all == null || all.size() <= 0){
                return null;
            }
            int length = all.size();
            //分页处理
            PageBean pageBean = new PageBean(pageSize,pageNo,length);
            int page = pageBean.getPageNo();
            int startIndex = (page -1) * pageSize;
            int endIndex = page * pageSize > length ? length : page * pageSize;
            List<T> tList = new ArrayList<>();
            for(int i = startIndex;i < endIndex;i++){
                tList.add(all.get(i));
            }
            return tList;
        }
    
        public static String[] getDescPageList(String[] all,int pageNo,int pageSize){
            if(all == null || all.length <= 0){
                return null;
            }
            int length = all.length;
            PageBean pageBean = new PageBean("desc",length,pageNo + "",pageSize);
            int endIndex = pageBean.getStartIndex() + 1;
            int startIndex = endIndex - pageBean.getPageSize();
            return getDescArray(Arrays.copyOfRange(all,startIndex,endIndex));
        }
    
        private static String[] getDescArray(String[] strings) {
            if(strings == null || strings.length <= 0){
                return null;
            }
            String[] arrays = new String[strings.length];
            for(int i = 0;i < arrays.length;i++){
                arrays[i] = strings[strings.length - 1 - i];
            }
            return arrays;
        }
    }

分页bean

package com.sms.tenantexamineserver.util;
    
    import org.apache.commons.lang3.StringUtils;
    import org.apache.commons.lang3.math.NumberUtils;
    
    /**
     * @Description TODO
     **/
    public class PageBean {
        //页码，默认页面是1
        private int pageNo = 1;
    
        //总页数
        private int totalPage = 0;
    
        //起始位置
        private int startIndex=0;
    
        //本页实际展示数
        private int pageSize = 0;
    
        //请求每页显示数
        private int reqPageSize;
    
        private int totalSize;
    
        public PageBean(int size, int page, int totalSize){
            reqPageSize = size <= 0 ? NumberUtils.toInt("10") : size;
            this.pageNo = page;
            this.totalSize = totalSize;
            if(size > 0){
                //计算总页数
                if(totalSize % size == 0){
                    //整除，正好每页显示pageSize条数据，没有多余一页要显示少于pageSize条数据的
                    this.totalPage = totalSize/size;
                }else{
                    //不整除，就要在加一页，来显示多余的数据。
                    this.totalPage = totalSize/size + 1;
                }
                // 计算当前页数
                if(page <= 0){
                    this.pageNo = 1;
                }
                if(page > totalPage){
                    this.pageNo = totalPage;
                }
                this.pageSize = size;
                //开始索引
                this.startIndex = (pageNo - 1)*size;
    
                // 设置需要展示的字数或者记录条数
                int length = this.startIndex + size;
                if(length > totalSize){
                    this.pageSize = totalSize - this.startIndex;
                }else{
                    this.pageSize = size;
                }
            }
        }
    
        /**
         * <一句话功能简述> <功能详细描述>
         * 
         * @param orderType 排序方式
         * @param total 总字数/总记录条数
         * @param page 当前页码
         * @param size 每页显示字数/每页显示记录条数
         * @return
         */
        public PageBean(String orderType, int total, String page, int size){
            this.reqPageSize = size;
            this.totalSize = total;
            if (!"desc".equals(orderType)){
                // 默认按正序排列
                orderType = "asc";
            }
            if(size == 0){
                return;
            }
            // 设置总页数
            if(total == 0){
                this.totalPage = 1;
            }else if(0 == total/size){
                this.totalPage = total/size;
            }else{
                this.totalPage = total/size + 1;
            }
    
            // 计算当前页码,输入的页面为空或非数字,则默认为1
            if(StringUtils.isEmpty(page) || !page.matches("\\d+")){
                page = "1";
            }
            //当前页
            this.pageNo = Integer.parseInt(page);
            // 页面大于总页数,则为总页数,少于1,则为1
            if(pageNo > totalPage){
                pageNo = totalPage;
            }else if (pageNo <= 0){
                pageNo = 1;
            }
            // 当前页图书起始阅读字节位置
            if(StringUtils.equals(orderType,"desc")){
                this.startIndex = total - ((pageNo - 1) * size);
                if(startIndex < 0){
                    startIndex =pageNo*size - total;
                }
    
                startIndex = startIndex - 1;
                // 设置需要展示的字数或者记录条数
                int length = this.startIndex - size;
                if(length < 0){
                    this.pageSize = startIndex + 1;
                }else{
                    this.pageSize = size;
                }
            }else{
                this.startIndex = (pageNo - 1)*size;
                // 设置需要展示的字数或者记录条数
                int length = this.startIndex + size;
                if(length > total){
                    this.pageSize = total - this.startIndex;
                }else{
                    this.pageSize = size;
                }
            }
        }
    
        public int getPageNo() {
            return pageNo;
        }
    
        public int getTotalPage() {
            return totalPage;
        }
    
        //起始位置，从0开始
        public int getStartIndex() {
            return startIndex;
        }
    
        //本页实际展示条数
        public int getPageSize() {
            return pageSize;
        }
    
        //分页请求，每页显示数
        public int getReqPageSize() {
            return reqPageSize;
        }
    
        //返回 totalSize
        public int getTotalSize() {
            return totalSize;
        }
    }