java 怎么利用正则表达式从给定的字符串中取出匹配规则字符串

Answer 1

import java.util.regex.*;
public class Email {
public static void main(String[] args) throws Exception {
String input = args[0];
//检测输入的EMAIL地址是否以 非法符号"."或"@"作为起始字符
Pattern p = Pattern.compile("^.|^@");
Matcher m = p.matcher(input);
if (m
//检测是否以"www."为起始
p = Pattern.compile("^www.");
m = p.matcher(input);
if (m
//检测是否包含非法字符
p = Pattern.compile("[^A-Za-z0-9.@_-~#]+");
m = p.matcher(input);
StringBuffer sb = new StringBuffer();
boolean result = m.find();
boolean deletedIllegalChars = false;
while(result) {
//如果找到了非法字符那么就设下标记
deletedIllegalChars = true;
//如果里面包含非法字符如冒号双引号等，那么就把他们消去，加到SB里面
m.appendReplacement(sb, "");
result = m.find();
}
m.appendTail(sb);
input = sb.toString();
if (deletedIllegalChars) {
System.out.println("输入的EMAIL地址里包含有冒号、逗号等非法字符，请修改");
System.out.println("您现在的输入为: "+args[0]);
System.out.println("修改后合法的地址应类似: "+input);
}
}
}