Java 集合的迭代操作 Iterator
几种实现 列出如下
1 import java.util.*; 2 3 /** 4 * Created by wojia on 2017/6/13. 5 */ 6 public class IteratorDemo { 7 public static void main(String args[]){ 8 List list = new ArrayList(); 9 list.add("A"); 10 list.add("B"); 11 list.add("C"); 12 list.add("D"); 13 System.out.println(list); 14 /*list 集合的迭代操作*/ 15 //1. for loop 16 for(int index = 0 ; index < list.size() ; index++){ //it's method which declared as size() , not a variable size. 17 Object temp = list.get(index); 18 System.out.print(temp); 19 20 } 21 System.out.println(); 22 23 //2. for - each loop 24 for(Object ele : list){ 25 System.out.print(ele); 26 } 27 System.out.println(); 28 29 //3. Use iterator 30 /**list.iterator will return an iterator Object*/ 31 Iterator iterator = list.iterator(); 32 while(iterator.hasNext()){ 33 System.out.print(iterator.next());//next()is a method 34 } 35 36 //4. Use for loop 37 /** 38 * this method is the best ,better than while loop , because of the gc 39 * */ 40 for(Iterator it = list.iterator();iterator.hasNext();){ 41 System.out.print(it.next()); 42 } 43 44 } 45 46 }
