应用 Collections.sort() 实现 List 排序 练习

public void testSort3() {
        List<String> stringList = new ArrayList<String>();
        String str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        Random random = new Random();
        for (int j = 0; j < 10; j++) {
            int x;
            StringBuffer st = new StringBuffer();
            do{
                x = random.nextInt(11);
                for (int i = 0; i < x; i++) {
                    st.append(str.charAt(random.nextInt(62)));
                }
            }while(stringList.contains(st)||x==0);
            stringList.add(st.toString());
        }
        System.out.println("---------------排序前---------------");
        for (String string : stringList) {
            System.out.println(string);
        }
        System.out.println("---------------排序后---------------");
        Collections.sort(stringList);
        for (String string : stringList) {
            System.out.println(string);
        }
    }