public void testChallenge() {

List <String> newst=new ArrayList<String>();

String substring="0123456789qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM";

? ? ? Random random=new Random();

for(int m=0;m<10;m++) {

StringBuilder sb=new StringBuilder();

? ?do{

? ?int? ss=random.nextInt(10);

for(int i=0;i<ss;i++ ) {

int sbint=random.nextInt(62);

sb.append(substring.charAt(sbint));

? ? ? ? ?}

? ? }while(newst.contains(sb));//保證字符串不重復

newst.add(sb.toString());

}

System.out.println("---------------排序前");

for(String st1:newst) {

System.out.println("排序前的字符串為："+st1);

}

System.out.println("----------排序后");

Collections.sort(newst );

for(String st1:newst) {

System.out.println("排序后的字符串為："+st1);

}

}