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在Java中输出集合Collection有四种方式，分别如下：

一）Iterator输出。 该方式适用于Collection的所有子类

public class Demo1{    public static void main(String[] args) throws Exception{        Set
   
     students=new HashSet
    
     ();        students.add(new Person("Bill",25));        students.add(new Person("Jack", 32));        students.add(new Person("Lily", 33));        students.add(new Person("Mike",65));        students.add(new Person("Jeason",33));                Iterator
     
       item = studnets.iterator();        while(item.hasNext()){            System.out.println(item.next());        }    }}
     
    
   

二）foreach输出。该方式适用于Collection的所有子类。

public class Demo2{    public static void main(String[] args) throws Exception{        Set
   
     students=new HashSet
    
     ();        students.add(new Person("Bill",25));        students.add(new Person("Jack", 32));        students.add(new Person("Lily", 33));        students.add(new Person("Mike",65));        students.add(new Person("Jeason",33));                for(Student item:students){            System.out.println(item);        }    }}
    
   

三）ListIterator。仅适用于List接口的子类。

public class Demo3{    public static void main(String[] args) throws Exception{        Set
   
     students=new HashSet
    
     ();        students.add(new Person("Bill",25));        students.add(new Person("Jack", 32));        students.add(new Person("Lily", 33));        students.add(new Person("Mike",65));        students.add(new Person("Jeason",33));                ListIterator
     
       item = students.listIterator();        System.out.println("正序输出:");        while(item.hasNext()){            System.out.println(item.next());        }        System.out.println("反序输出:");        while(item.hasPrevious()){            System.out.println(item.previous());        }    }}
     
    
   

四）Enumeration输出。仅适用于Vector类。

public class Demo4{    public static void main(String[] args) throws Exception{        Set
   
     students=new HashSet
    
     ();        students.add(new Person("Bill",25));        students.add(new Person("Jack", 32));        students.add(new Person("Lily", 33));        students.add(new Person("Mike",65));        students.add(new Person("Jeason",33));                Enumeration
     
       item = students.elements();        while(item.hasMoreElements()){            System.out.println(item.nextElement());        }    }}
     
    
   

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