JAVA练习集合类：去除ArrayList中的重复元素

一、去除ArrayList中的重复元素

public class Person {
    public String name;
    public int age;
    public Person(String name,int age){
        this.name = name;
        this.age = age;
    }

    public boolean equals(Object obj){      //覆盖equals方法
        if(this == obj)
            return true;
        if(!(obj instanceof Person)){
            throw new ClassCastException("类型错误");
        }
        Person p = (Person) obj;
        return this.name.equals(p.name) && this.age == p.age;
    }
}

import java.util.ArrayList;
import java.util.Iterator;

public class ArrayListTest {
    public static void main(String[] args) {
        ArrayList a1 = new ArrayList();
        a1.add(new Person("abc1",1));
        a1.add(new Person("abc2",1));
        a1.add(new Person("abc1",1));
        a1.add(new Person("abc2",1));
        a1.add(new Person("abc",1));

       // a1 = getSingleElement(a1);     //去除字符串
        a1 = getSingleElement2(a1);       //去除自定义对象
        Iterator it = a1.iterator();
        while(it.hasNext()){
            Person p = (Person)it.next();
            System.out.println(p.name+"...."+p.age);
        }
    }

    private static ArrayList getSingleElement2(ArrayList a1) {
        //定义临时容器
        ArrayList temp = new ArrayList();
        //迭代集合
        Iterator it = a1.iterator();

        while(it.hasNext()){
            Object obj = it.next();
            //判断被迭代到的元素是否在临时容器中存在
            if(!temp.contains(obj)){
                temp.add(obj);
            }
        }
        return temp;
    }

    public static ArrayList getSingleElement(ArrayList a1) {
        //定义临时容器
        ArrayList temp = new ArrayList();
        //迭代集合
        Iterator it = temp.iterator();

        while(it.hasNext()){
            Object obj = it.next();
            //判断被迭代到的元素是否在临时容器中存在
            if(!temp.contains(obj)){
                temp.add(obj);
            }
        }
        return temp;
    }


}