Java -- HashMap的四种遍历方式

方法一

Map<String, String> map = new HashMap<String, String>();
for (Entry<String, String> entry : map.entrySet()) {
String key = entry.getKey();
String value = entry.getValue();
System.out.println("key = " + key);
System.out.println("value = " + value);
}

方法二

Map<String, String> map = new HashMap<String, String>();
Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry<String, String> entry = iterator.next();
String key = entry.getKey();
String value = entry.getValue();
System.out.println("key = " + key);
System.out.println("value = " + value);
}

方法三

Map<String, String> map = new HashMap<String, String>();
for (String key : map.keySet()) {
String value = map.get(key);
System.out.println("value = " + value);
}

方法四

Map<String, String> map = new HashMap<String, String>();
Set<Entry<String, String>> entrySet = map.entrySet();
for (Entry<String, String> entry : entrySet) {
String key = entry.getKey();
String value = entry.getValue();
System.out.println("key = " + key);
System.out.println("value = " + value);
}