//Map的四种遍历方法

//Map不能直接遍历 ，只能通过遍历Key与Value间接遍历

public static void main(String[] args) {

@H_404_19@ Map<String,String> map = new HashMap<String,String>();@H_404_19@ map.put("1","value1");@H_404_19@ map.put("2","value2");@H_404_19@ map.put("3","value3");@H_404_19@@H_404_19@ //第一种：普遍使用，二次取值@H_404_19@ System.out.println("通过Map.keySet遍历key和value：");@H_404_19@ for (String key : map.keySet()) {@H_404_19@ System.out.println("key= "+ key + " and value= " + map.get(key));@H_404_19@ }@H_404_19@@H_404_19@ //第二种@H_404_19@ System.out.println("通过Map.entrySet使用iterator遍历key和value：");@H_404_19@ Iterator<Map.Entry<String,String>> it = map.entrySet().iterator();@H_404_19@ while (it.hasNext()) {@H_404_19@ Map.Entry<String,String> entry = it.next();@H_404_19@ System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());@H_404_19@ }@H_404_19@@H_404_19@ //第三种：推荐，尤其是容量大时@H_404_19@ System.out.println("通过Map.entrySet遍历key和value");@H_404_19@ for (Map.Entry<String,String> entry : map.entrySet()) {@H_404_19@ System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());@H_404_19@ }

//第四种@H_404_19@ System.out.println("通过Map.values()遍历所有的value，但不能遍历key");@H_404_19@ for (String v : map.values()) {@H_404_19@ System.out.println("value= " + v);@H_404_19@ }@H_404_19@ }