Map对象的遍历方法

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1. 如果键值都要

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

2. 如果使用的语言版本低于java 5，或是打算在遍历时删除 条目

//使用泛型：
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 + ", Value = " + value);
}
//不使用泛型：
Iterator iterator = map.entrySet().iterator();
while (iterator.hasNext()) {
	Map.Entry entry = (Map.Entry) iterator.next();
	String key = (String)entry.getKey();
	String value = (String)entry.getValue();
	System.out.println("Key = " + key + ", Value = " + value);
}

3. 如果仅需要键(keys)或值(values)

//遍历map中的键
for (String key : map.keySet()) {
	System.out.println("Key = " + key );
}
//遍历map中的值
for (String value : map.values()) {
	System.out.println("Value = " + value);
}