java map 遍历

Map<String, String> map = new HashMap<String, String>();
map.put("a", "aaa");
map.put("b", "bbb");
map.put("c", "ccc");

// for
for (Map.Entry<String, String> entry : map.entrySet()) {
	System.out.println(entry.getKey() + "_" + entry.getValue());
}

// 迭代
Set set = map.entrySet();
Iterator it = set.iterator();
while (it.hasNext()) {
	Map.Entry<String, String> entry1 = (Map.Entry<String, String>) it.next();
	System.out.println(entry1.getKey() + "_" + entry1.getValue());
}

// keySet()迭代
Iterator keyIt = map.keySet().iterator();
while (keyIt.hasNext()) {
	String key;
	String value;
	key = keyIt.next().toString();
	value = map.get(key);
	System.out.println(key + "_" + value);
}

// entrySet()迭代
Iterator entryIt = map.entrySet().iterator();
String key;
String value;
while (entryIt.hasNext()) {
	Map.Entry entry = (Map.Entry) entryIt.next();
	key = entry.getKey().toString();
	value = entry.getValue().toString();
	System.out.println(key + "_" + value);
}