获取到一个list 怎么分页？

ゝ一世哀愁。 2023-08-17 17:39 87阅读 0赞

1 public SearchResult paging(List<T> list, int pageNumber, int pageSize) throws Exception{
     2         List<T> pageList = new ArrayList<T>();
     3         int currIdx = (pageNumber > 1 ? (pageNumber -1) * pageSize : 0);
     4         for (int i = 0; i < pageSize && i < list.size() - currIdx; i++){
     5             T listNew = list.get(currIdx + i);
     6             pageList.add(listNew);
     7         }
     8         SearchResult<T> searchResult = new SearchResult<T>();
     9         searchResult.setList(pageList);
    10         searchResult.setTotal(list.size());
    11         if (searchResult.getTotal()%pageSize == 0){
    12             searchResult.setPages((int)searchResult.getTotal()/pageSize);
    13         }else {
    14             searchResult.setPages((int)searchResult.getTotal()/pageSize + 1);
    15         }
    16         searchResult.setPageNum(pageNumber);
    17         searchResult.setPageSize(pageSize);
    18         searchResult.setSize(pageList.size());
    19         //是否是第一页
    20         if (pageNumber == 1){
    21             searchResult.setIsFirstPage(true);
    22         }else {
    23             searchResult.setIsFirstPage(false);
    24         }
    25         //是否是最后一页
    26         if ((searchResult.getTotal() - pageNumber*pageSize) > 0){
    27             searchResult.setIsLastPage(false);
    28         }else {
    29             searchResult.setIsLastPage(true);
    30         }
    31         return searchResult;
    32     }

public class PageInfo<T> implements Serializable {
        
        private static final long serialVersionUID = 1L;
        //当前页
        private int pageNum;
        //每页的数量
        private int pageSize;
        //当前页的数量
        private int size;
        //排序
        private String orderBy;
    
        //由于startRow和endRow不常用，这里说个具体的用法
        //可以在页面中"显示startRow到endRow 共size条数据"
    
        //当前页面第一个元素在数据库中的行号
        private int startRow;
        //当前页面最后一个元素在数据库中的行号
        private int endRow;
        //总记录数
        private long total;
        //总页数
        private int pages;
        //结果集
        private List<T> list;
    
        //前一页
        private int prePage;
        //下一页
        private int nextPage;
    
        //是否为第一页
        private boolean isFirstPage = false;
        //是否为最后一页
        private boolean isLastPage = false;
        //是否有前一页
        private boolean hasPreviousPage = false;
        //是否有下一页
        private boolean hasNextPage = false;
        //导航页码数
        private int navigatePages;
        //所有导航页号
        private int[] navigatepageNums;
        //导航条上的第一页
        private int navigateFirstPage;
        //导航条上的最后一页
        private int navigateLastPage;
    
        public PageInfo() {
        
        }
    
        /**
         * 包装Page对象
         *
         * @param list
         */
        public PageInfo(List<T> list) {
        
            this(list, 8);
        }
    
        /**
         * 包装Page对象
         *
         * @param list          page结果
         * @param navigatePages 页码数量
         */
        public PageInfo(List<T> list, int navigatePages) {
        
            if (list instanceof Page) {
        
                Page page = (Page) list;
                this.pageNum = page.getPageNum();
                this.pageSize = page.getPageSize();
                this.orderBy = page.getOrderBy();
    
                this.pages = page.getPages();
                this.list = page;
                this.size = page.size();
                this.total = page.getTotal();
                //由于结果是>startRow的，所以实际的需要+1
                if (this.size == 0) {
        
                    this.startRow = 0;
                    this.endRow = 0;
                } else {
        
                    this.startRow = page.getStartRow() + 1;
                    //计算实际的endRow（最后一页的时候特殊）
                    this.endRow = this.startRow - 1 + this.size;
                }
            } else if (list instanceof Collection) {
        
                this.pageNum = 1;
                this.pageSize = list.size();
    
                this.pages = 1;
                this.list = list;
                this.size = list.size();
                this.total = list.size();
                this.startRow = 0;
                this.endRow = list.size() > 0 ? list.size() - 1 : 0;
            }
            if (list instanceof Collection) {
        
                this.navigatePages = navigatePages;
                //计算导航页
                calcNavigatepageNums();
                //计算前后页，第一页，最后一页
                calcPage();
                //判断页面边界
                judgePageBoudary();
            }
        }
    
        /**
         * 计算导航页
         */
        private void calcNavigatepageNums() {
        
            //当总页数小于或等于导航页码数时
            if (pages <= navigatePages) {
        
                navigatepageNums = new int[pages];
                for (int i = 0; i < pages; i++) {
        
                    navigatepageNums[i] = i + 1;
                }
            } else { //当总页数大于导航页码数时
                navigatepageNums = new int[navigatePages];
                int startNum = pageNum - navigatePages / 2;
                int endNum = pageNum + navigatePages / 2;
    
                if (startNum < 1) {
        
                    startNum = 1;
                    //(最前navigatePages页
                    for (int i = 0; i < navigatePages; i++) {
        
                        navigatepageNums[i] = startNum++;
                    }
                } else if (endNum > pages) {
        
                    endNum = pages;
                    //最后navigatePages页
                    for (int i = navigatePages - 1; i >= 0; i--) {
        
                        navigatepageNums[i] = endNum--;
                    }
                } else {
        
                    //所有中间页
                    for (int i = 0; i < navigatePages; i++) {
        
                        navigatepageNums[i] = startNum++;
                    }
                }
            }
        }
    
        /**
         * 计算前后页，第一页，最后一页
         */
        private void calcPage() {
        
            if (navigatepageNums != null && navigatepageNums.length > 0) {
        
                navigateFirstPage = navigatepageNums[0];
                navigateLastPage = navigatepageNums[navigatepageNums.length - 1];
                if (pageNum > 1) {
        
                    prePage = pageNum - 1;
                }
                if (pageNum < pages) {
        
                    nextPage = pageNum + 1;
                }
            }
        }
    
        /**
         * 判定页面边界
         */
        private void judgePageBoudary() {
        
            isFirstPage = pageNum == 1;
            isLastPage = pageNum == pages;
            hasPreviousPage = pageNum > 1;
            hasNextPage = pageNum < pages;
        }
    
        public int getPageNum() {
        
            return pageNum;
        }
    
        public void setPageNum(int pageNum) {
        
            this.pageNum = pageNum;
        }
    
        public int getPageSize() {
        
            return pageSize;
        }
    
        public void setPageSize(int pageSize) {
        
            this.pageSize = pageSize;
        }
    
        public int getSize() {
        
            return size;
        }
    
        public void setSize(int size) {
        
            this.size = size;
        }
    
        public String getOrderBy() {
        
            return orderBy;
        }
    
        public void setOrderBy(String orderBy) {
        
            this.orderBy = orderBy;
        }
    
        public int getStartRow() {
        
            return startRow;
        }
    
        public void setStartRow(int startRow) {
        
            this.startRow = startRow;
        }
    
        public int getEndRow() {
        
            return endRow;
        }
    
        public void setEndRow(int endRow) {
        
            this.endRow = endRow;
        }
    
        public long getTotal() {
        
            return total;
        }
    
        public void setTotal(long total) {
        
            this.total = total;
        }
    
        public int getPages() {
        
            return pages;
        }
    
        public void setPages(int pages) {
        
            this.pages = pages;
        }
    
        public List<T> getList() {
        
            return list;
        }
    
        public void setList(List<T> list) {
        
            this.list = list;
        }
    
        @Deprecated
        // firstPage就是1, 此函数获取的是导航条上的第一页, 容易产生歧义
        public int getFirstPage() {
        
            return navigateFirstPage;
        }
    
        @Deprecated
        public void setFirstPage(int firstPage) {
        
            this.navigateFirstPage = firstPage;
        }
    
        public int getPrePage() {
        
            return prePage;
        }
    
        public void setPrePage(int prePage) {
        
            this.prePage = prePage;
        }
    
        public int getNextPage() {
        
            return nextPage;
        }
    
        public void setNextPage(int nextPage) {
        
            this.nextPage = nextPage;
        }
    
        @Deprecated
        // 请用getPages()来获取最后一页, 此函数获取的是导航条上的最后一页, 容易产生歧义.
        public int getLastPage() {
        
            return navigateLastPage;
        }
    
        @Deprecated
        public void setLastPage(int lastPage) {
        
            this.navigateLastPage = lastPage;
        }
    
        public boolean isIsFirstPage() {
        
            return isFirstPage;
        }
    
        public void setIsFirstPage(boolean isFirstPage) {
        
            this.isFirstPage = isFirstPage;
        }
    
        public boolean isIsLastPage() {
        
            return isLastPage;
        }
    
        public void setIsLastPage(boolean isLastPage) {
        
            this.isLastPage = isLastPage;
        }
    
        public boolean isHasPreviousPage() {
        
            return hasPreviousPage;
        }
    
        public void setHasPreviousPage(boolean hasPreviousPage) {
        
            this.hasPreviousPage = hasPreviousPage;
        }
    
        public boolean isHasNextPage() {
        
            return hasNextPage;
        }
    
        public void setHasNextPage(boolean hasNextPage) {
        
            this.hasNextPage = hasNextPage;
        }
    
        public int getNavigatePages() {
        
            return navigatePages;
        }
    
        public void setNavigatePages(int navigatePages) {
        
            this.navigatePages = navigatePages;
        }
    
        public int[] getNavigatepageNums() {
        
            return navigatepageNums;
        }
    
        public void setNavigatepageNums(int[] navigatepageNums) {
        
            this.navigatepageNums = navigatepageNums;
        }
    
        public int getNavigateFirstPage() {
        
            return navigateFirstPage;
        }
    
        public int getNavigateLastPage() {
        
            return navigateLastPage;
        }
    
        public void setNavigateFirstPage(int navigateFirstPage) {
        
            this.navigateFirstPage = navigateFirstPage;
        }
    
        public void setNavigateLastPage(int navigateLastPage) {
        
            this.navigateLastPage = navigateLastPage;
        }
    
        @Override
        public String toString() {
        
            final StringBuffer sb = new StringBuffer("PageInfo{");
            sb.append("pageNum=").append(pageNum);
            sb.append(", pageSize=").append(pageSize);
            sb.append(", size=").append(size);
            sb.append(", startRow=").append(startRow);
            sb.append(", endRow=").append(endRow);
            sb.append(", total=").append(total);
            sb.append(", pages=").append(pages);
            sb.append(", list=").append(list);
            sb.append(", prePage=").append(prePage);
            sb.append(", nextPage=").append(nextPage);
            sb.append(", isFirstPage=").append(isFirstPage);
            sb.append(", isLastPage=").append(isLastPage);
            sb.append(", hasPreviousPage=").append(hasPreviousPage);
            sb.append(", hasNextPage=").append(hasNextPage);
            sb.append(", navigatePages=").append(navigatePages);
            sb.append(", navigateFirstPage").append(navigateFirstPage);
            sb.append(", navigateLastPage").append(navigateLastPage);
            sb.append(", navigatepageNums=");
            if (navigatepageNums == null) sb.append("null");
            else {
        
                sb.append('[');
                for (int i = 0; i < navigatepageNums.length; ++i)
                    sb.append(i == 0 ? "" : ", ").append(navigatepageNums[i]);
                sb.append(']');
            }
            sb.append('}');
            return sb.toString();
        }
    }

转载于:https://www.cnblogs.com/pan-my/p/11458915.html