迭代器的使用

范例：

package cn.study.lu.four;

import java.util.*;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class TestIterator {
public static void main(String[] args) {
testIteratorList();
testIteratorSet();
testIteratotMap();
}




public static void testIteratorList() {
List<String> list = new ArrayList<String>();
list.add("aaa");
list.add("bbb");
list.add("ccc");
list.add("ddd");

for (Iterator<String> iter = list.iterator();iter.hasNext();) {
String temp = iter.next();
System.out.println(temp);
}
}


public static void testIteratorSet() {
Set<String> set = new HashSet<String>();
set.add("111");
set.add("222");
set.add("333");
set.add("444");

for (Iterator<String> iter = set.iterator();iter.hasNext();) {
String temp = iter.next();
System.out.println(temp);
}
}

public static void testIteratotMap() {
Map<Integer, String> map1 = new HashMap<Integer, String>();
map1.put(111, "aaa");
map1.put(222, "bbb");
map1.put(333, "ccc");
map1.put(444, "ddd");

/**/Set<Entry<Integer,String>> ss = map1.entrySet();
//第一种遍历map的方式
for (Iterator<Entry<Integer, String>> iter = ss.iterator();iter.hasNext();) {
Entry<Integer, String> temp = iter.next();
System.out.println(temp.getKey()+"---"+temp.getValue());
}

System.out.println("--------------------------------------------");

//第二种遍历map的方式
Set<Integer> keyset = map1.keySet();
for (Iterator<Integer> iter = keyset.iterator();iter.hasNext();) {
Integer temp = iter.next();
System.out.println(temp+"---"+map1.get(temp));
}
}
}