| 获取该字符串中每一个字母出现的个数    “GZITCASTADVANCEDTRAININGJAVASEJAVAEE ANDROID”   import java.util.TreeMap;   public class Test5 {  public static void main(String[] args) {     String str = null;   try {         str = "GZITCASTADVANCEDTRAININGJAVASEJAVAEE ANDROID";       }  catch (Exception e)      {       e.printStackTrace();      }   Map tree = new TreeMap();     for (int i = 0; i < str.length(); i++) {    char ch = str.charAt(i);    if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z')) {     if (!tree.containsKey(ch)) {      tree.put(ch, new Integer(1));     } else {      Integer in = (Integer) tree.get(ch) + 1;      tree.put(ch, in);     }    }   }   Iterator tit = tree.keySet().iterator();   while (tit.hasNext()) {    Object temp = tit.next();    System.out.print(temp.toString() + "(" + tree.get(temp) + ")");   }  } } 输出:A(9)C(2)D(4)E(4)G(2)I(4)J(2)N(4)O(1)R(2)S(2)T(3)V(3)Z(1) |