BBS_笔记

日期格式化：

<%=new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(a.getPdate()) %> 

id传值必须的判断：

	String strid = request.getParameter("id");
	if(strid==null||strid.trim().equals("")){
		out.print("id error!");
		return;
	}
	int id = 0;
	try{
		id = Integer.parseInt(strid);
	}catch(NumberFormatException e){
		out.print("id error again!");
		return;
	}

关于中文乱码需要转码两种方式：

request.setCharacterEncoding("utf8");
	
String title = new String(request.getParameter("title").getBytes("8859_1"),"utf-8");
String cont = new String(request.getParameter("cont").getBytes("8859_1"),"utf-8");

对于自动生成key获取办法：

PreparedStatement st = DB.createPstmt(conn,sql,Statement.RETURN_GENERATED_KEYS);
ResultSet rs = st.getGeneratedKeys();
rs.next();
rootId = rs.getInt(1);

事物处理：

conn.setAutoCommit(false);
。。。。
conn.commit();
conn.setAutoCommit(true);

读秒返回到首页：

<script type="text/javascript">
function toUrl(url){
	window.location.href=url;
}
</script>
 <script type="text/javascript">
 	function delayTime(){
  	var time = document.getElementById("time").innerHTML;
  	if(time>0){
  		time--;
  		document.getElementById("time").innerHTML=time;
  		setTimeout("delayTime()",1000);
  	}else{
	  	var url ="article.jsp";
	  	toUrl(url);
  	}
 	}
</script>

分页处理：

final int PAGE_SIZE = 4; //每页显示数量
int totalPages = 0;//总页数
int totalRecords = 0;//总记录数
int pageNo =1; //页码（当前第pageNo页）  
String pno = request.getParameter("pageNo");
if(pno!=null&&!pno.trim().equals("")){
	try{
		pageNo = Integer.parseInt(pno);
	}catch(NumberFormatException e){
		pageNo = 1;
	}
}
if(pageNo<=0)
	pageNo=1;
List<Article> articles = new ArrayList<Article>();
Connection conn = DB.getConn();
Statement stmt = DB.createStmt(conn);
ResultSet rs = DB.executeSql(stmt, "select count(*) from article where pid=0");
if(rs.next()){
	totalRecords = rs.getInt(1);
}
totalPages = (totalRecords+PAGE_SIZE-1)/PAGE_SIZE;//常用算法，算出总页数
if(pageNo>totalPages)
	pageNo = totalPages;
int startPos = (pageNo-1)*PAGE_SIZE;
Statement st = DB.createStmt(conn);
ResultSet r = DB.executeSql(st, "select * from article where pid=0 limit "+startPos+","+PAGE_SIZE);
while(r.next()){
	Article a = new Article();
	a.artFormrs(r);
	articles.add(a);
}

DB.close(rs);
DB.close(stmt);
DB.close(conn);