过滤空格字符

public static void replaceBlank()  
{  
Pattern p = Pattern.compile("\\s*|\t|\r|\n");  
String str="I am a, I am Hello ok, \n new lineffdsa!";  
System.out.println("before:"+str);  
Matcher m = p.matcher(str);  
String after = m.replaceAll("");  
System.out.println("after:"+after);  
}