java--去重练习

方法一：
package com.test;
import java.util.ArrayList;
import com.bean.Student;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Random;
import java.util.Scanner;

import com.bean.Student;
public class qiantao_1 {

public static void main(String[] args) {
	//extracted_3();
	Scanner  sc = new Scanner(System.in);
	System.out.println("please String");
	HashSet<Character> hs= new  HashSet<>();
	String line = sc.nextLine();
	char[] arr = line.toCharArray();
	for(char c: arr) {
		hs.add(c);
	}
	for(Character ch :hs) {
		
	}
            System.out.println(hs);
}

方法二：

package com.test;
import com.bean.Student;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Random;
import java.util.Scanner;

import com.bean.Student;
public class qiantao_1 {

public static void main(String[] args) {
	//extracted_4();
	ArrayList<String> list = new ArrayList<>();
	list.add("a");
	list.add("a");
	list.add("b");
	list.add("b");
	list.add("b");
	getSingLe(list);
	System.out.println(list);
}
     private static void getSingLe(List<String> list) {      //定义去重方法
	LinkedHashSet<String> lhs =new LinkedHashSet();
	lhs.addAll(list);
	list.clear();
	list.addAll(lhs);
}