大家帮忙研究下这个问题!

[chb_2000_0]

import java.util.*;

public class SearchString{
public static void main(String argv[])
{
Pattern p = Pattern.compile("a*b");
Matcher m = p.matcher("aaaaab");
boolean b = m.matches();
System.out.println(b);
}
}

编译出现如下错误

SearchString.java:1: cannot resolve symbol
symbol : class regex
location: package util
import java.util.regex;
^
SearchString.java:6: cannot resolve symbol
symbol : class Pattern
location: class SearchString
Pattern p = Pattern.compile("a*b");
^
SearchString.java:6: cannot resolve symbol
symbol : variable Pattern
location: class SearchString
Pattern p = Pattern.compile("a*b");
^
SearchString.java:7: cannot resolve symbol
symbol : class Matcher
location: class SearchString
Matcher m = p.matcher("aaaaab");
^
4 errors

jdk的版本是1.4.2