Map遍历

Map<String, String> map = new HashMap<String, String>();
map.put("1", "PHP");
map.put("2", "Java");
map.put("3", "C");
map.put("4", "C++");
map.put("5", "HTML");

// keySet()方法，获取map集合中的所有键
Set<String> set = map.keySet();
for (String key : set){
    String value = map.get(key);
    System.out.println(key+":"+value);
}

// entrySet()方法，获取map集合中的每一个键值对
Set<Map.Entry<String,String>> set =  map.entrySet();
for (Map.Entry<String,String> entry : set){
    String key = entry.getKey();
    String value = entry.getValue();
    System.out.println(key+":"+value);
}

3:C
2:Java
1:PHP
5:HTML
4:C++