Java 去除 ArrayList 集合中的重复元素

// One practice
package Collection;

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

// 去除 ArrayList 集合中的重复元素
public class ArrayListTest
{
	public static void sop(Object obj)
	{
		System.out.println(obj);
	}

	public static void main(String[] args)
	{
		ArrayList<String> arrayList = new ArrayList<String>();

		arrayList.add("java01");
		arrayList.add("java02");
		arrayList.add("java03");
		arrayList.add("java04");
		arrayList.add("java01");
		arrayList.add("java02");
		arrayList.add("java03");

		sop(arrayList);
		arrayList = singleElement(arrayList);
		sop(arrayList);

	}

	public static ArrayList<String> singleElement(ArrayList<String> al)
	{
		// 定义一个临时容器
		ArrayList newAl = new ArrayList();
		Iterator iterator = al.iterator();
		while (iterator.hasNext())
		{
			Object obj = iterator.next();
			if (!newAl.contains(obj))
			{
				newAl.add(obj);
			}
		}
		return newAl;
	}
}

// Practice Two

package Collection;

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

// 将自定义对象作为元素存到 ArrayList 集合中，并去除重复元素
// 比如：存人对象。同姓名同年龄，视为同一个人。为重复元素

/*
1.对人描述，将数据封装进入对象
2.定义容器，将人存入
3.取出

List集合判断元素是否相同，依据是元素的 equals 方法。
*/

class Person
{
	private String name;
	private int age;
	Person(String name,int age)
	{
		this.name = name;
		this.age = age;
	}
	// 重写 equals 方法
	public boolean equals(Object obj)
	{
		if (!(obj instanceof Person))
		{
			return false;
		}
		Person person = (Person)obj;
		return this.name.equals(person.name) && this.age == person.age;
	}

	public String getname()
	{
		return name;
	}
	public int getage()
	{
		return age;
	}

}

public class ArrayListTest2
{
	public static void sop(Object obj)
	{
		System.out.println(obj);
	}

	public static void main(String[] args)
	{
		ArrayList al = new ArrayList();
		al.add(new Person("Xp01", 30));
		al.add(new Person("Xp02", 35));
		al.add(new Person("Xp02", 35));
		al.add(new Person("Xp03", 37));
		al.add(new Person("Xp04", 35));
		al.add(new Person("Xp04", 35));

		al = singleElement(al);

		Iterator it = al.iterator();

		while (it.hasNext())
		{
			Person p = (Person)it.next();
			sop(p.getname()+"::"+p.getage());
		}
	}

	public static ArrayList singleElement(ArrayList<String> al)
	{
		// 定义一个临时容器
		ArrayList newAl = new ArrayList();
		Iterator iterator = al.iterator();
		while (iterator.hasNext())
		{
			Object obj = iterator.next();
			if (!newAl.contains(obj))
			{
				newAl.add(obj);
			}
		}
		return newAl;
	}
}