分页算法（三）

	/**
	 * 分页器（评论）：上一页 1 ... 8 9 10 11 12 13 14 ... 16 下一页
	 * @param totalRows	总记录数
	 * @param pageSize	每页显示记录数
	 * @param start		开始记录数
	 * @param bizData	业务参数
	 * @param displayCount	跨度
	 * @param actionUrl	因为链接
	 * @return
	 */
	public static String pagerComment(int totalRows, int pageSize, int start, 
			Map<Object, Object> bizData, int displayCount, String actionUrl) {
		//参数检验
		if (start <= 0 || start > totalRows || pageSize <= 0) {
			return "";
		}
		
		start =  (start - 1) * pageSize + 1;
		
		//计算总页数
		int totalPages = 1;
		if (totalRows != pageSize) {
			totalPages = (int) Math.ceil((double) totalRows / (double) pageSize);
		}
		//计算当前页
		int currentPage = start / pageSize;
		if (start % pageSize != 0) {
			currentPage ++;
		}
		//计算左右跨度显示的起始页
		int low = currentPage - displayCount > 0 ? currentPage - displayCount : 1;
		int high = currentPage + displayCount;
		
		StringBuilder pageBuilder = new StringBuilder(100);
		
		//总记录数小于每页记录数，则只显示一页
		if (totalRows <= pageSize) {
			pageBuilder.append(new ATag("javascript:void(0);", new HashMap<Object, Object>(), "1", STYLE_ACTIVE));
		//当前页是中间某一页
		} else {
			//当前页不是第一页，则显示“上一页”
			if (currentPage > 1) {
				bizData.put("start", (currentPage - 1));
				pageBuilder.append(new ATag(actionUrl, bizData, "上一页", STYLE_NON_ACTIVE));
			}
			
			if (low - 1 > 1) {
				bizData.put("start", 1);
				pageBuilder.append(new ATag(actionUrl, bizData, "1", STYLE_NON_ACTIVE));
				
				pageBuilder.append("<span>...</span>");
				
				while(low < currentPage) {
					bizData.put("start", low);
					pageBuilder.append(new ATag(actionUrl, bizData, "" + low++, STYLE_NON_ACTIVE));
				}
			} else {
				low = 1;
				while(low < currentPage) {
					bizData.put("start", low);
					pageBuilder.append(new ATag(actionUrl, bizData, "" + low++, STYLE_NON_ACTIVE));
				}
			}
			
			pageBuilder.append(new ATag("javascript:void(0);", new HashMap<Object, Object>(), "" + currentPage, STYLE_ACTIVE));
			
			int temp = currentPage + 1;
			if (totalPages - high > 1) {
				while(temp <= high) {
					bizData.put("start", temp);
					pageBuilder.append(new ATag(actionUrl, bizData, "" + temp++, STYLE_NON_ACTIVE));
				}
				
				pageBuilder.append("<span>...</span>");
				
				bizData.put("start", totalPages);
				pageBuilder.append(new ATag(actionUrl, bizData, "" + totalPages, STYLE_NON_ACTIVE));
			} else {
				while(temp <= totalPages) {
					bizData.put("start", temp);
					pageBuilder.append(new ATag(actionUrl, bizData, "" + temp++, STYLE_NON_ACTIVE));
				}
			}
			
			//当前页不是最后一页，则显示“下一页”
			if (currentPage < totalPages) {
				bizData.put("start", currentPage + 1);
				pageBuilder.append(new ATag(actionUrl, bizData, "下一页", STYLE_NON_ACTIVE));
			}
		} 
		return pageBuilder.toString();
	}