JSP 網站建設 分頁技巧

在BBS論壇中常用到分頁，自己總結的分頁技巧如下：

<%
final int PAGE_SIZE = 4;//定義每頁要顯示的頁數爲一個final變量
int pageNo = 1;
String strPageNo = request.getParameter("pageNo");//拿到傳到本頁面的pageNo
//對pageNo 進行判斷
if(strPageNo != null && !strPageNo.trim().equals("")) {
    try {
        pageNo = Integer.parseInt(strPageNo);//用Integer包裝類把strPageno 轉化爲int 類型
    } catch (NumberFormatException e) {
        pageNo = 1;
    }
}
if(pageNo <= 0) pageNo = 1;//對pageNo小於0的情況進行判斷
//int totalPages;//給總頁面數一個初值
List<Article> articles = new ArrayList<Article>();//new 一個list容器裝數據
Connection conn = DB.getConn();//拿到鏈接
Statement stmtCount = DB.createStmt(conn);//拿到Statement
ResultSet rsCount = DB.executeQuery(stmtCount, "select count(*) from article where pid = 0");//因爲是平板型展現,從數據庫中取出pid爲0的帖子
rsCount.next();//遍歷
int totalRecords = rsCount.getInt(1);//
//第一種計算所有頁數的方法
//totalPages = (totalRecords + PAGE_SIZE - 1)/PAGE_SIZE;
//算出所有的頁數（第二種方法）
int  totalPages = totalRecords % PAGE_SIZE == 0 ? totalRecords/ PAGE_SIZE : totalRecords / PAGE_SIZE + 1;/
if(pageNo > totalPages) pageNo = totalPages;//如果頁號比總頁數要少，把總頁數賦給頁號
Statement stmt = DB.createStmt(conn);
int startPos = (pageNo-1) * PAGE_SIZE; //起始位置爲頁數-1後再乘以每頁要顯示的頁數
String sql = "select * from article where pid = 0 order by pdate desc limit " + startPos + "," + PAGE_SIZE ;
System.out.println(sql);
ResultSet rs = DB.executeQuery(stmt, sql);
while(rs.next()) {
    Article a = new Article();
    a.initFromRs(rs);
    articles.add(a);
}
DB.close(rsCount);
DB.close(stmtCount);
DB.close(rs);
DB.close(stmt);
DB.close(conn);
%>