传统方法:
第一种:
@Test public void test1() { Map m =new HashMap(); //显示的是3,2,1 //Map m =new LinkedHashMap(); //显示的是1,2,3 m.put("1","aaaa"); m.put("2","baaa"); m.put("3","caaa"); Set set = m.keySet(); Iterator it = set.iterator(); while(it.hasNext()) { String key = (String) it.next(); String value = (String) m.get(key); System.out.println(key+"----"+value); } }
显示:
3----caaa
2----baaa
1----aaaa
第二种:
@Test public void test2() { //Map m =new HashMap(); //显示的是3,2,1 Map m =new LinkedHashMap(); //显示的是1,2,3 m.put("1","aaaa"); m.put("2","baaa"); m.put("3","caaa"); Set set = m.entrySet(); Iterator it = set.iterator(); while(it.hasNext()) { Map.Entry entry = (Entry) it.next(); String key = (String) entry.getKey(); String value = (String) entry.getValue(); System.out.println(key+"----"+value); } }
显示:
1----aaaa
2----baaa
3----caaa
for加强版本:
第一种:
@Test public void test3() { //Map m =new HashMap(); //显示的是3,2,1 Map m =new LinkedHashMap(); //显示的是1,2,3 m.put("1","aaaa"); m.put("2","baaa"); m.put("3","caaa"); for(Object o: m.keySet()) { String key = (String) o; String value = (String) m.get(key); System.out.println(key+"----"+value); } }
@Test public void test4() { //Map m =new HashMap(); //显示的是3,2,1 Map m =new LinkedHashMap(); //显示的是1,2,3 m.put("1","aaaa"); m.put("2","baaa"); m.put("3","caaa"); for(Object o:m.entrySet()) { Map.Entry entry = (Entry) o; String key = (String) entry.getKey(); String value = (String) entry.getValue(); System.out.println(key+"----"+value); } }