JSP操作技巧(摘自www.java-cn.com)

[/b]JSP操作[/b]技巧(摘自www.java-cn.com)
[/b]
[/b]1 [/b]表单的另一种参数传递方法：
[/b]<form name="form1<%=id%>" method="post" action="bookOrder.jsp?bookid=<%=id%>">
<img src="images/all1.gif" width="40" height="40" onClick="submit()"></form>
2 防止为登陆浏览： if(session.getAttribute("UserName")==null||session.getAttribute("UserName")=="")
{
out.println("<Script language=′javascript′>");
out.println("alert(′对不起！请你登陆后再订阅′)");
out.println("history.go(-1)");
out.println("</script>");
}
else
{
%>
3[/b]验证 [/b]用户信息的合法性：
[/b]
<%@ 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");//得到数量
if(bookNumS!=""&bookNumS!=null)
{
try
{
bookNumI=Integer.parseInt(bookNumS);//转换成int类型
Id=Integer.parseInt(bookid) ;
}
catch(NumberFormatException e) { out.println("<Script language=′javascript′>");
out.println("alert(′对不起,您输入的数字格式不对!′)");
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(′您已经订过此书！′)"); out.println("history.back(-1)"); out.println("</script>"); } } bookM.bclose(); }%> 4[/b]表单的检验
[/b]<form action="search.jsp" name="search_form" methor="post"> <input type="submit" name="Submit3" value="确定" onclick=search_sub()> <script language="javascript"> function search_sub() { if(document.search_form.keyword.value==""|document.search_form.keyword.value=="请输入关键字") { window.alert("请输入关键字!"); document.search_form.keyword.focus(); return; } else
{ document.search_form.submit(); } } 5[/b]搜索的sql[/b]代码：[/b]
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+"%′"; } //////////////书名******************** if(way.trim().equals("1"))
{ strSQL="SELECT * FROM hotbook where";
strSQL=strSQL+" 书名 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[/b]分页显示
[/b]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;//每页实际页数 int pageNO=1;//第几页 int pageRecorders=5;//每页10条记录 int pageTotal=RSa.getRow();//共几条 int pageCount=pageTotal/pageRecorders;//每页10条共几页 String strPage = request.getParameter("pagenum");//得到传递上来的页数 if(strPage==null) { //表明在QueryString中没有page这一个参数，此时显示第一页数据 pageNO = 1; } else { //将字符串转换成整型 pageNO= java.lang.Integer.parseInt(strPage); if(pageNO<1) {pageNO = 1;} } if(pageCount>=0) { //将记录指针定位到待显示页的第一条记录//的前一条上 if((pageNO-1)==0)//如果为第一页，则指向第0条 { RSa.beforeFirst();//如果为第一条记录， } else RSa.absolute((pageNO-1) * pageRecorders);//如果为其它，则指向当前条的下一条 } %> <table width="772" border="0"> <tr> <td width="120"><%if (session.getAttribute("UserName")!=null) { out.println("<font color=red>欢迎您："+session.getAttribute("UserName")+"</font>");} else { out.println("<font color=red>请您登陆!</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">查看全部热点书</a></td> <td width="126"><a href="myorder.jsp" target="_blank">查看我的订单</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("书名"); String writer=RSa.getString("作者"); float sale2=RSa.getFloat("定价"); 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%>","详细资料",600,300)><img src="image/hotbook/<%=image%>.jpg" border="0"></a></td> <td valign=top width="58%" ><b>书名:</b><a href=javascript:show("../search_info.jsp?id=<%=bookid%>","详细资料",600,300)><font color="#cc0000"><b><%= bookname%></b></font></a><br> <b><br>作者:</b><%=writer%><br> <b>定价:</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′>本页有"+qikan_num+"条纪录，共找到"+pageTotal+"条</font></b></p>"); out.println("<font color=′#cc00000′ size=′2′>当前是第"+pageNO+"页</font>"); out.println("页数"); 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[/b]另一种 [/b]删除数据后，跳转的方法
[/b]<% 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[/b]将 [/b]年月日转换的方法 [/b]如 2004-05-02 2004[/b]年5[/b]月2[/b]日
[/b]<%! 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 [/b]中文转换
[/b]<%! 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 [/b]用户注销 [/b]代码
[/b]<% session.setAttribute("UserName",""); session.setAttribute("station",""); session.setAttribute("id",""); response.sendRedirect("default.jsp"); %> 第二篇[/b]
[/b]1 [/b]防止用户刷新页面，等待10[/b]秒
[/b]// 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>对不起，服务器正在运行时，请勿刷新页面，谢谢合作，如有不便敬请谅解</p> <p>页面将于10秒后重新回到主页.......请等待！！！</p>
<%response.setHeader("Refresh","10;URL=default.jsp");%> 2[/b]用javaBean[/b]调用javascript[/b]指令
[/b]//jsp try{ studentID=(String)session.getAttribute("studentID"); if(studentID==null){ throw new Exception(); } }catch(Exception e){ Tools.showalert("您还没有登录，或连接超时，请重新登录!",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[/b]用javaBean [/b]返回
[/b]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[/b]用bean [/b]插入javascript
[/b]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()); } }