如何用Jsp判断接收的值的特殊性质？？

全部可以用javascript完成。判断是不是特殊字符可以判断他们的ASCII值是否在大写A到小写z的之间。判断数字可以用函数isNaN()

用javascript，下面为一个例子
<script language="javascript">
  function on_check(){
      if(form1.workid.value==""){
   alert("电子卡号不能为空？");
form1.workid.focus();
return false;
  }
  if(form1.workid.value.length!=0&&form1.workid.value.length==8){
      for(i=0;i<form1.workid.value.length;i++)
   if(form1.workid.value.charAt(i)<"9"&&form1.workid.value.charAt(i)>"0")
break;
if(i==form1.workid.value.length){
alert("不能输入其它字符，只能为数字!");
            form1.workid.focus();
        return false;
}
  }else{
   alert("你输入长度不对!");
       form1.workid.focus();
    return false;

  }
}
</script>

用JSP（JAVA）如何实现。主要是防止恶意攻击。？？？

最简单的方法：判断ascii码就行了

<%String name = request.getParameter("name");

if (name.equals("")) {
System.out.println("不能为空");%>

<jsp:forward page="MyJsp.jsp"/>

<%}
if (name.equals("") || (name.indexOf('@') != -1)
|| (name.indexOf('.') != -1) || (name.indexOf('#') != -1)
|| (name.indexOf('￥') != -1) || (name.indexOf('%') != -1) || (name.indexOf('^') != -1)) {

System.out.println("不能输入特殊字符!");
}
else{
System.out.println("正确");
} %>

<jsp:forward page="MyJsp.jsp"/>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>My JSP 'MyJsp.jsp' starting page</title>

    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">

    
  </head>

  <body>
    <table width="100%" border="0" cellspacing="0" cellpadding="4">  <tr>     <td bgcolor="#000099">       <table width="100%" border="0" cellspacing="0" cellpadding="4">        <tr>                     <td width="100%"><font color="#CCCCCC">  <font color="#FFFFFF"><strong>Title</strong></font></font></td>        </tr>      </table></td>  </tr>  <tr>      <td width="100%" bgcolor="#EAEAEA" colspan="2">       <form name="form1" id="form1" action="post.jsp"><p>
          <label for="textfield">Field 1: </label>          <input type="text" name="name" id="name">        </p>        <p>           <input type="submit" name="Submit" value="Submit">        </p>    </form>  </td>  </tr></table>
  </body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>
My JSP 'post.jsp' starting page
</title> <meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page"> </head> <body>
<%String name = request.getParameter("name");

   if (name.equals("")) {
System.out.println("不能为空");%>

<jsp:forward page="MyJsp.jsp"/>

<%}
if (name.equals("") || (name.indexOf('@') != -1)
|| (name.indexOf('.') != -1) || (name.indexOf('#') != -1)
|| (name.indexOf('￥') != -1) || (name.indexOf('%') != -1) || (name.indexOf('^') != -1)) {

System.out.println("不能输入特殊字符!");
}
else{
   System.out.println("正确");
} %>

<jsp:forward page="MyJsp.jsp"/>


</body>
</html>

这个当然还是要用正则表达式做了　　< %@ page import="java.util.regex.*"%>　　< %　　Pattern p=null; //正则表达式　　Matcher m=null; //操作的字符串　　boolean b;　　String s=null;　　StringBuffer sb=null;　　int i=0;　　//字符串匹配，这是不符合的　　p = Pattern.compile("a*b");　　m = p.matcher("baaaaab");　　b = m.matches();　　out.println(b+"< br>");　　//字符串匹配，这是符合的

guileen(松风抚琴) 方法好，思路没看明白？？

第2种情况也可以直接转INT或其他数据型，只要CATCH异常就可以了

import java.util.regex.*;

    public class BasicMatch {
        public static void main(String[] args) {
            // Compile regular expression
            String patternStr = "b";
            Pattern pattern = Pattern.compile(patternStr);

            // Determine if pattern exists in input
            CharSequence inputStr = "a b c b";
            Matcher matcher = pattern.matcher(inputStr);
            boolean matchFound = matcher.find();    // true

            // Get matching string
            String match = matcher.group();         // b

            // Get indices of matching string
            int start = matcher.start();            // 2
            int end = matcher.end();                // 3
            // the end is index of the last matching character + 1

            // Find the next occurrence
            matchFound = matcher.find();            // true
        }
    }

import java.util.regex.*;public class RegexExample {    public static void main(String[] args)
    {
        Pattern p = Pattern.compile("\\$(\\d+)");
        Matcher m = p.matcher("it costs $4");        boolean found = m.find();
        if( found )
        {
            String foundstring = m.group();
            System.out.println(foundstring);

            int beginPos = m.start();
            int endPos = m.end();
            System.out.println("start:" + beginPos + "\nend:" + endPos);            String found1 = m.group(1); // 括号内匹配内容
            System.out.println(found1);
        }    }
}

package com;import java.util.regex.*;public class pattern { public static void main(String[] args) {

Pattern p = Pattern.compile("\\$(\\d+)");// 自己编写的正则表达式

Matcher m = p.matcher("it costs $23");// 需要验证的字符串

boolean found = m.find();// 查找匹配的字符

if (found) {

String foundstring = m.group();// 将匹配的字符放入foundstring中

System.out.println(foundstring); int beginPos = m.start();// 匹配的第一个字符的前一位

int endPos = m.end();// 匹配字符的最后一位

System.out.println("start:" + beginPos + "\nend:" + endPos);

String found1 = m.group(1); // 括号内匹配内容

System.out.println(found1);
}
String result = m.replaceAll("￥$1");

System.out.println(result);
}
}

调试易

如何用Jsp判断接收的值的特殊性质？？

解决方案 »