关于正则表达式

String chinese = "^[\\u4E00-\\u9FA5\\uF900-\\uFA2D]"; /**这个正则表达式用来判断是否为中文**/ 
                    String username = "^\\w";/**此正则表达式判断单词字符是否为：[a-zA-Z_0-9]**/ 
             
                     /**此正则表达式将上面二者结合起来进行判断，中文、大小写字母和数字**/ 
                    String all  = "^[\\u4E00-\\u9FA5\\uF900-\\uFA2D\\w]{2,10}";//{2,10}表示字符的长度是2-10  
                    Pattern pattern = Pattern.compile(all);
                    Pattern pattern = Pattern.compile(username);
                    boolean tf = pattern.matcher("8*").matches(); 
                    boolean tf1 = Pattern.matches(all, "&&&");  
                    System.out.println(tf);
                    System.out.println(tf1);
                  
               /*   \\u4E00-\\u9FA5\\uF900-\\uFA2D是指汉字的Unicode编码范围  
                  \w是指单词字符：[a-zA-Z_0-9]  */