集合集合集合大神赐教 - 黑马程序员技术交流社区

package ListTest;
import java.util.*;
//将自定义对象作为元素储存在Arraylist数组中，并去除重复元素
//定义一个Person类对外提供Get Set方法
class Person{
private String name;
private int age;
Person(String name,int age){
this.name=name;
this.age=age;
}
public String getName (){
return name;
}
public int getAge(){
return age;
}
//提供对象比较的Eqeals方法
public boolean equals(Object obj){
if (!(obj instanceof Person) ){
return false;
}
Person p = (Person)obj;
return this.name.equals(p.name) && this.age==p.age;
}
}
public class ArratListDemo {
public static void sop(Object obj){
System.out.println(obj);
}
public static void main(String[] args) {
ArrayList al = new ArrayList();
al.add(new Person("java01", 1));// al.add("java01",1) ==Object obj = new Person("java01", 1);向上提升，在存储时候编译错误 Obj中没有.getname()
al.add(new Person("java02", 2));
al.add(new Person("java03", 3));
al.add(new Person("java04", 4));
al.add(new Person("java01", 1));
al=singleElement(al);
//打印姓名年龄
Iterator it = al.iterator();
while (it.hasNext()) {
//Object obj = it.next();
//Person p = (Person) obj;
Person p = (Person)it.next();
sop("name :"+p.getName()+"---Age :"+p.getAge());
}
}
//定义去除重复元素方法
public static ArrayList singleElement(ArrayList al)
{
//定义容器
ArrayList newal = new ArrayList();
Iterator it= al.iterator();
while (it.hasNext()) {
Object obj = it.next();
if (!newal.equals(obj)) {
newal.add(obj);
}
}
return newal;
}
}

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