List集合之ArrayList

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1，创建Person类

public class Person {
	private String name;
	private Integer age;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}

	public Person(String name,Integer age){
		this.name = name;
		this.age = age;
	}
	@Override
	//重写toString方法
	public String toString() {
		// TODO Auto-generated method stub
		return name+":"+age;
	}
	@Override
	//重写hashcode方法
	public int hashCode() {
		// TODO Auto-generated method stub
		return this.name.hashCode()+age*37;
	}
	@Override
	//重写equals方法
	public boolean equals(Object obj) {
		// TODO Auto-generated method stub
		if(!(obj instanceof Person)){
			return false;
		}
		Person p = (Person)obj;
		return this.name.equals(p.name)&&this.age==p.age;
	}
	
}

2，主方法，去除ArrayList中重复的元素。

public static void main(String[] args) {
		//创建Person对象
		Person p1 = new Person("zhangsan", 12);
		Person p2 = new Person("lisi", 17);
		Person p3 = new Person("wangwu", 19);
		Person p4 = new Person("zhangsan", 12);
		Person p5 = new Person("zhangsan", 13);
		//将对象添加到集合中
		ArrayList list = new ArrayList();
		list.add(p1);
		list.add(p2);
		list.add(p3);
		list.add(p4);
		list.add(p5);
		//判断是否重复并添加
		ArrayList list2 = new ArrayList();
		for (int i = 0; i < list.size(); i++) {
			Object obj = list.get(i);
			if (!(obj instanceof Person)) {
				list2.add(obj);
			}
			Person p = (Person) obj;

			if (!(list2.contains(p))) {
				list2.add(p);

			}

		}
		System.out.println(list);
		System.out.println(list2);

	}

ArrayList是使用最多 的一个集合类