/**

• 1.创建完List<String>之后，往其中添加十条随机字符串
• 2.每条字符串的长度为10以内的随机整数
• 3.每条字符串的每个字符都为随机生成的字符，字符可以重复
• 4.每条随机字符串不重复
• @param args
  */
  public void testExercise() {
  List<String> stringList = new ArrayList<String>();
  Random random = new Random();
  String base="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  for(int i = 0;i < 10;i++) {
  StringBuilder str = new StringBuilder();
  int k = random.nextInt(10);//每条字符串的长度
  do {
  for(int j = 0;j < k;j++) {
  int num = random.nextInt(base.length());
  str.append(base.charAt(num));
  }
  } while (stringList.contains(str.toString()));
  stringList.add(str.toString());
  }
  System.out.println("------------------排序前--------------");
  for (String string : stringList) {
  System.out.println("元素：" + string);
  }
  Collections.sort(stringList);
  System.out.println("------------------排序后--------------");
  for (String string : stringList) {
  System.out.println("元素：" + string);
  }
  }