java中常见的几种list 转换成 Array 对象

java中有常见的几种list或者集合 类型: Vector, ArrayList, LinkedList,TreeSet LinkedHashSet. 很有可能为了方便，会将这些对象转换成数组. 下面记录一些常见的用法:

Vector 转换成 Array

 // Create a Vector and populate it with elements
    Vector vector = new Vector();
    vector.add("element_1");
    vector.add("element_2");
    vector.add("element_3");
    vector.add("element_4");
    vector.add("element_5"); 

    Object[] objArray = vector.toArray();
 
    System.out.println("Elements in Array :");
    for(int i=0; i < objArray.length ; i++)
         System.out.println(objArray[i]);

// Create an ArrayList and populate it with elements
    ArrayList arrayList = new ArrayList();
    arrayList.add("element_1");
    arrayList.add("element_2");
    arrayList.add("element_3");
    arrayList.add("element_4"); 
  
    Object[] objArray = arrayList.toArray();
 
    System.out.println("Elements in Array :");
    for(int i=0; i < objArray.length ; i++)
        System.out.println(objArray[i]);

 // Create a LinkedList and populate it with elements
    LinkedList linkedList = new LinkedList();
    linkedList.add("element_1");
    linkedList.add("element_2");
    linkedList.add("element_3");
    linkedList.add("element_4");
    linkedList.add("element_5");
   
    Object[] objArray = linkedList.toArray();
 
    System.out.println("Elements in Array :");
    for(int i=0; i < objArray.length ; i++)
         System.out.println(objArray[i]);

 HashSet hashSet = new HashSet();
    hashSet.add("element_1");
    hashSet.add("element_2");
    hashSet.add("element_3"); 
  
    Object[] objArray = hashSet.toArray();
 
    System.out.println("Elements in Array :");
    for(int i=0; i < objArray.length ; i++)
        System.out.println(objArray[i]);

 TreeSet treeSet = new TreeSet();
    treeSet.add("element_1");
    treeSet.add("element_2");
    treeSet.add("element_3");
   
    Object[] objArray = treeSet.toArray();
 
    System.out.println("Elements in Array :");
    for(int i=0; i < objArray.length ; i++)
        System.out.println(objArray[i]);

    LinkedHashSet linkedHashSet = new LinkedHashSet();
    linkedHashSet.add("element_1");
    linkedHashSet.add("element_2");
    linkedHashSet.add("element_3");
   
    Object[] objArray = linkedHashSet.toArray();
 
    System.out.println("Elements in Array :");
    for(int i=0; i < objArray.length ; i++)
        System.out.println(objArray[i]);