jsp中email格式限制问题！sun给的例子便宜不通！！！
大家好！下面是老师给的sun的例子，我没改过！ 但是为什么编译不同呢？谢谢大家帮忙看以下！

/*
* Checks for invalid characters
* in email addresses
*/
public class EmailValidation {
public static void main(String[] args)
throws Exception {
try{
String input = "123@sun.com ";
//Checks for email addresses starting with
//inappropriate symbols like dots or @ signs.
Pattern p = Pattern.compile( "^\\.|^\\@ ");
Matcher m = p.matcher(input);
if (m.find())
System.err.println( "Email addresses don 't start " +
" with dots or @ signs. ");

//Checks for email addresses that start with
//www. and prints a message if it does.
p = Pattern.compile( "^www\\. ");
m = p.matcher(input);
if (m.find()) {
System.out.println( "Email addresses don 't start " +
" with \ "www.\ ", only web pages do. ");
}
p = Pattern.compile( "[^A-Za-z0-9\\.\\@_\\-~#]+ ");
m = p.matcher(input);
StringBuffer sb = new StringBuffer();
boolean result = m.find();
boolean deletedIllegalChars = false;

while(result) {
deletedIllegalChars = true;
m.appendReplacement(sb, " ");

result = m.find();
}

// Add the last segment of input to the new String
m.appendTail(sb);

input = sb.toString();

if (deletedIllegalChars) {
System.out.println( "It contained incorrect characters " +
" , such as spaces or commas. ");
}
}catch(Exception e){System.out.print(e.toString());}
}
}

[解决办法]
这种验证别进到后台在验证，在页面就先过滤掉，这里是个比较简单的JS验证
function checkEmail(){
var email=t_hotel_hnmc.f_SAFETY_EMAIL_HOTE.value;
var filter=/^[A-Za-z0-9][A-Za-z0-9_-]*@[A-Za-z0-9_-]+\.[A-Za-z0-9_.]+[A-za-z]$/;

if (email.length> 0)
{
if (filter.test(email))
return true;
else
alert( "请输入一个合法的电子信箱地址! " );
}
return false;
}