JSP操作技巧(摘自www.java-cn.com)
1 表單的另一種參數傳遞方法：
<form name="form1<%=id%>" method="post" action="bookOrder.jsp?bookid=<%=id%>">
<img src="images/all1.gif" width="40" height="40" onClick="submit()"></form>
2 防止爲登陸瀏覽：
if(session.getAttribute("UserName")==null||session.getAttribute("UserName")=="")
{
out.println("<Script language=′javascript′>");
out.println("alert(′對不起！請你登陸後再訂閱′)");
out.println("history.go(-1)");
out.println("</script>");
}
else
{
%>
3驗證 用戶信息的合法性：
<%@ page language="java" import="java.sql.*" %>
<jsp:useBean id="bookM" scope="page" class="date.SearchBookCar" />
<%! String bookid,bookNumS; int Id,bookNumI;
%>
<%
bookid=request.getParameter("bookid");//得到ID
bookNumS=request.getParameter("bookfield");//得到數量
if(bookNumS!=""&bookNumS!=null)
{
try
{
bookNumI=Integer.parseInt(bookNumS);//轉換成int類型
Id=Integer.parseInt(bookid) ;
}
catch(NumberFormatException e)
{
out.println("<Script language=′javascript′>");
out.println("alert(′對不起,您輸入的數字格式不對!′)");
out.println("history.back(-1)");
out.println("</script>");
}
boolean one=bookM.bookQuery(Id,bookNumI,""+session.getAttribute("loginTime"),""+session.getAttribute("UserName"));
if(one)
{
out.println("<Script language=′javascript′>");
out.println("alert(′提交成功!′)");
out.println("history.back(-1)");
out.println("</script>");
}
else
{
out.println("<Script language=′javascript′>");
out.println("alert(′您已經訂過此書！′)");
out.println("history.back(-1)");
out.println("</script>");
}
}
bookM.bclose();
}
%>
4表單的檢驗
<form action="search.jsp" name="search_form" methor="post">
<input type="submit" name="Submit3" value="確定" onclick=search_sub()>
<script language="javascript">
function search_sub()
{
if(document.search_form.keyword.value==""|document.search_form.keyword.value=="請輸入關鍵字")
{
window.alert("請輸入關鍵字!");
document.search_form.keyword.focus();
return;
}
else
{
document.search_form.submit();
}
}
5搜索的sql代碼：
String strSQL="Select * from hotbook";
if(way!=null&&keyword!=null)
{
//////////////出版社********************
if(way.trim().equals("3"))
{
strSQL="SELECT * FROM hotbook where";
strSQL=strSQL+" 出版社 like "+"′%"+keyword+"%′";
}
//////////////出版日期********************
if(way.trim().equals("4"))
{
strSQL="SELECT * FROM hotbook where";
strSQL=strSQL+" 出版日期 like ′%"+keyword+"%′";
}
//////////////書名********************
if(way.trim().equals("1"))
{
strSQL="SELECT * FROM hotbook where";
strSQL=strSQL+" 書名 like ′%"+keyword+"%′";
}
//////////////作者********************
if(way.trim().equals("2"))
{
strSQL="SELECT * FROM hotbook where";
strSQL=strSQL+" 作者 like ′%"+keyword+"%′";
}
//////////////ISBN********************
if(way.trim().equals("5"))
{
strSQL="SELECT * FROM hotbook where";
strSQL=strSQL+" ISBN like ′%"+keyword+"%′";
}
}
6分頁顯示
if (strSQL!=null)
{
Connection con=yy.getConn();
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
ResultSet RSa=stmt.executeQuery(strSQL);
RSa.last();
int qikan_num=0;//每頁實際頁數
int pageNO=1;//第幾頁
int pageRecorders=5;//每頁10條記錄
int pageTotal=RSa.getRow();//共幾條
int pageCount=pageTotal/pageRecorders;//每頁10條共幾頁
String strPage = request.getParameter("pagenum");//得到傳遞上來的頁數
if(strPage==null)
{
//表明在QueryString中沒有page這一個參數，此時顯示第一頁數據
pageNO = 1;
}
else
{
//將字符串轉換成整型
pageNO= java.lang.Integer.parseInt(strPage);
if(pageNO<1)
{pageNO = 1;}
}
if(pageCount>=0)
{
//將記錄指針定位到待顯示頁的第一條記錄//的前一條上
if((pageNO-1)==0)//如果爲第一頁，則指向第0條
{
RSa.beforeFirst();//如果爲第一條記錄，
}
else RSa.absolute((pageNO-1) * pageRecorders);//如果爲其它，則指向當前條的下一條
}
%>
<table width="772" border="0">
<tr>
<td width="120"><%if (session.getAttribute("UserName")!=null)
{ out.println("<font color=red>歡迎您："+session.getAttribute("UserName")+"</font>");}
else
{ out.println("<font color=red>請您登陸!</font>"); };%>
</td>
<%if(pageNO<=pageCount){%>
<td width="128">
<a href="../search.jsp?pagenum=<%=pageNO+1%>&keyword=<%=keyword%>&way=<%=way%>">下一</a></td>
<%}%>
<%if(pageNO>1){%>
<td width="124">
<a href="../search.jsp?pagenum=<%=pageNO-1%>&keyword=<%=keyword%>&way=<%=way%>">上一</a></td>
<%}%>
<td width="124"> </td>
<td width="124"><a href="search.jsp">查看全部熱點書</a></td>
<td width="126"><a href="myorder.jsp" target="_blank">查看我的訂單</a></td>
</tr>
</table>
</td>
</tr>
</table>
<table width="660" border=0 align="center" cellpadding=6 cellspacing=0 class=linehight height="123">
<%
while( RSa.next()&&qikan_num<pageRecorders)
{
String bookname= RSa.getString("書名");
String writer=RSa.getString("作者");
float sale2=RSa.getFloat("定價");
String pubname= RSa.getString("出版社");
String pubtime= RSa.getString("出版日期");
int bookid= RSa.getInt("id");
String image= RSa.getString("ISBN");
%>
<tr>
<td align=middle width="23%" height=16>
<a href=javascript:show("../search_info.jsp?id=<%=bookid%>","詳細資料",600,300)>
<img src="image/hotbook/<%=image%>.jpg" border="0"></a></td>
<td valign=top width="58%" ><b>書名:</b>
<a href=javascript:show("../search_info.jsp?id=<%=bookid%>","詳細資料",600,300)><font color="#cc0000"><b><%= bookname%></b></font></a><br>
<b><br>作者:</b><%=writer%><br>
<b>定價:</b><font color="#cc0000"> ￥<%=sale2%></font><br>
<b>出版社:</b><%=pubname%><br>
<b>出版日期:</b><%=pubtime%></td>
<td valign=bottom width="19%" height=16 >
<form name="form1<%=bookid%>" method="post"
action="bookTiqiao.jsp?bookid=<%=bookid%>">
<input type="text" name="bookfield" size="3" maxlength="3" value="1">
本<img src="images/all1.jpg" width="41" height="36" onClick="submit()" style="cursor:hand">
</form>
</td>
</tr>
<tr align=middle>
<td valign=top colspan=3 height=0>
<div align="right"><img src="images/search_end.gif" width="424" height="15"></div>
</td>
</tr>
<%
qikan_num++;
}
%>
</table>
<table width="772" border="0" align="center">
<tr>
<td><%
out.println("<p><b><font color=′#174572′ size=′2′>本頁有"+qikan_num+"條紀錄，共找到"+pageTotal+"條</font></b></p>");
out.println("<font color=′#cc00000′ size=′2′>當前是第"+pageNO+"頁</font>");
out.println("頁數");
for(int i=1;i<pageCount+2;i++)
{
%>
<a href="../search.jsp?pagenum=<%=i%>&keyword=<%=keyword%>&way=<%=way%>"><u><%=i%></u></a>
<%
}
RSa.close();
stmt.close();
con.close();
}%>
</td>
</tr>
</table>
7另一種 刪除數據後，跳轉的方法
<%
if (session.getAttribute("UserName")==null)
{
response.sendRedirect("../index.jsp");
}
else
{
String keyword1,SQL;
keyword1=request.getParameter("bookid");
SQL="Delete From bookdindan Where ??????id=′"+keyword1+"′";
Connection con=yy.getConn();
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
stmt.executeUpdate(SQL);
response.sendRedirect("../myorder.jsp");
stmt.close();
con.close();
}
%>
8將 年月日轉換的方法 如 2004-05-02 2004年5月2日
<%!
public static String YMD(String dt)
{
try
{
return dt.substring(0,4)+"年"+dt.substring(5,7)+"月"+dt.substring(8,10)+"日";
}
catch(Exception e)
{
}
return "null";
}
%>
9 中文轉換
<%!
public String getStr(String str)
{
try
{
String temp_p=str;
byte[] temp_t=temp_p.getBytes("GBK");
String temp=new String(temp_t,"ISO8859_1");
return temp;
}
catch(Exception e)
{
}
return "null";
}
10 用戶註銷 代碼
<%
session.setAttribute("UserName","");
session.setAttribute("station","");
session.setAttribute("id","");
response.sendRedirect("default.jsp");
%>
第二篇
1 防止用戶刷新頁面，等待10秒
// default.jsp
<%
String aaa="b"+session.getAttribute("nF");
if(!aaa.equals("bnull"))
{
session.setAttribute("nF",null);
response.sendRedirect("1.jsp");
}
else
{
session.setAttribute("nF","a");
%>
//1.jsp
<%@ page contentType="text/html; charset=gb2312"%>
<%@ page language="java" %>
<p>對不起，服務器正在運行時，請勿刷新頁面，謝謝合作，如有不便敬請諒解</p>
<p>頁面將於10秒後重新回到主頁.......請等待！！！</p>
<%response.setHeader("Refresh","10;URL=default.jsp");%>
2用javaBean調用javascript指令
//jsp
try{
studentID=(String)session.getAttribute("studentID");
if(studentID==null){
throw new Exception();
}
}catch(Exception e){
Tools.showalert("您還沒有登錄，或連接超時，請重新登錄!",out);
Tools.showJS("window.open(′../login.jsp′,′_self′)",out);
}
//Bean
import javax.servlet.jsp.JspWriter;
public static void showalert(String msg, JspWriter out)
{
try
{
out.print(String.valueOf(String.valueOf((new StringBuffer("<SCRIPT
LANGUAGE=/"javascript/"/n> alert(/"")).append(msg).append("/");/n").append("</SCRIPT>/n"))));
}
catch(Exception e)
{
System.out.println(e.toString());
}
}
3用javaBean 返回
public static void goback(JspWriter out)
{
try
{
out.print("<SCRIPT LANGUAGE=/"javascript/"/n> history.go(-1);/n</SCRIPT>/n");
}
catch(Exception e)
{
System.out.println(e.toString());
}
}
4用bean 插入javascript
public static void goback(JspWriter out)
{
try
{
out.print("<SCRIPT LANGUAGE=/"javascript/"/n> history.go(-1);/n</SCRIPT>/n");
}
catch(Exception e)
{
System.out.println(e.toString());
}
}