collection类

 Collection<String> c =new ArrayList<String>();//存储string类型 //实例化

//添加元素add();
        c.add("hello");
        c.add("world");
        c.add("java");
        System.out.println(c);

 System.out.println(c.remove("hello"));

c.clear();
System.out.println(c.isEmpty());

System.out.println(c.contains("world"));

 Iterator<String> it =c.iterator() ;

   if(it.hasNext()){
            System.out.println(it.next());
            
        }

  while(it.hasNext()){
         System.out.println(it.next());

     }

  while(it.hasNext()){
         String s=it.next();
         System.out.println(s);

     }

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Collection;
import java.util.ArrayList;
//定义学生类
//创建collection对象
//创建学生对象
//把学生添加到集合
public class collectiondemo {
    public static  void main(String[] args) {
        Collection<Student> c=new ArrayList<Student>();
        Student s1=new Student("1",19);
        Student s2=new Student("2",18);
        Student s3=new Student("3",20);

        c.add(s1);
        c.add(s2);
        c.add(s3);
        //遍历集合
        Iterator<Student> it =c.iterator();
        while(it.hasNext()){
            Student s=it.next();
            System.out.println(s.getName()+s.getAge());


        }


    }

}
 class Student {
    private String name;
    private int age;


     public Student(String name,int age){
         this.name=name;
         this.age=age;

     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }
 }