import java.util.ArrayList;
import java.util.List;
public class Test2 {
 /**
  * @param args
  */
 public static void main(String[] args) {
  String src = "A B C D E B C";
  //替換掉空格
  src = src.replaceAll(" ", "") ;

  System.out.println("去除空格后字符串：" + src) ;
  List<Character> list = new ArrayList<Character>() ;
  int[] bb = new int[256];  
  char[] cs = src.toCharArray();  

  //倒序
  int mid = cs.length / 2 ;
  int idx = cs.length -1 ;
  for (int i = 0; i < mid ; i++){
   char tmp = cs[i] ;
   cs[i] = cs[idx] ;
   cs[idx] = tmp ;
   idx-- ;
  }
  //統計，并且過濾相同的
  for (char c : cs) { 
   if (bb[c] <1) {
    list.add(c) ;
   }
   bb[c] = bb[c] + 1;  
     }
  System.out.println();
  for (int i = 0; i < list.size(); i++){
   System.out.print(list.get(i)) ;
  }
  System.out.println() ;

  for (int i = 0; i < list.size(); i++){
   char c = list.get(i) ;

   System.out.println(c + " " + bb[c] + "次") ;
  }

 }
}

 * 
 * @author Java人(java2000.net)
*/ 
public class Test { 
  /**
   * @param args
   */ 
  public static void main(String[] args) { 
    String a = "abcd,efg"; 
    String b = ")(*&^%$#@![]{},.///;:'? <>"; 
    byte[] bb = new byte[256]; 
    char[] cs = b.toCharArray(); 
    for (char c : cs) { 
      bb[c] = 1; 
    } 
    cs = a.toCharArray(); 
    for (char c : cs) { 
      if (bb[c] == 1) { 
        System.out.println(c); 
      } 
    } 
  } 
}