package?com.imooc.student;

import?java.util.ArrayList;
import?java.util.Collections;
import?java.util.List;
import?java.util.Random;


public?class?RandomString?{
	private?List<String>?list?;
	public?RandomString(){
		this.list=?new?ArrayList<String>();
	}
	public?void?stringRandom(){
		String?string?=?"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
		Random?random?=?new?Random();
		int?length=0;
		for(int?i=0;i<10;i++){
			String?str="";
			do?{
				str="";
				length=random.nextInt(9)+1;
				for(int?j=0;j<length;j++){
					char?cr=string.charAt(random.nextInt(string.length()-1));
					str+=cr;
				}
			}?while?(list.contains(str));
			list.add(str);
		}
	}
	public?void?stringSort(){
		System.out.println("排序前:");
		for?(String?string?:?list)?{
			System.out.println(string);
		}
		Collections.sort(list);
		System.out.println("排序后:");
		for?(String?string?:?list)?{
			System.out.println(string);
		}
	}
	public?static?void?main(String[]?args)?{
		RandomString?rs?=?new?RandomString();
		rs.stringRandom();
		rs.stringSort();
	}

}

當list.contains(str)判斷為true的時候！如果str語句不清空的話！str語句是不是會在重復的基礎上增加！ 這樣是不是會超過規定的長度了！雖然幾率很小！ ?但是這也是有可能的吧！ ?