使用迭代器遍历集合的内容：
1.通过调用集合的Iterator（）方法，获取指向集合开头的迭代器。
2.建立一个hasNext（）方法调用循环。只要hasNext（）方法返回true，就继续迭代。
3.在循环中，通过调用next（）方法获取每个元素。
package Collection; import java.util.ArrayList; import java.util.Iterator; import java.util.ListIterator; /** * @author 犀角 * @date 2019/11/2 9:49 * @description 使用迭代器遍历集合的内容 */ public class IteratorDemo { public static void main(String[] args) { //create an Array list ArrayList<String> arrayList = new ArrayList<String>(); arrayList.add("q"); arrayList.add("e"); arrayList.add("fg"); arrayList.add("iu"); arrayList.add("ug"); //Use Iterator display contents of arraylist. System.out.println("Original contents of arraylist: "); Iterator<String> iterator = arrayList.iterator(); while (iterator.hasNext()){ String element = iterator.next(); System.out.print(element +" "); } System.out.println(); //Modify objects being iterated ListIterator<String> lit = arrayList.listIterator(); while (lit.hasNext()){ String element = lit.next(); lit.set(element + "+"); } System.out.println("Modified contents of arraylist: "); iterator = arrayList.iterator(); while (iterator.hasNext()){ String element = iterator.next(); System.out.print(element + " "); } System.out.println(); //Now,display the list backwards. System.out.println("Modified list backwards: "); while (lit.hasPrevious()){ String element = lit.previous(); System.out.print(element + " "); } System.out.println(); } }
