entrySet 跟keySet

entrySet 和keySet

public class MapList {
?? public static void main(String[] args) {
??? Map<String, Object> map = new HashMap<String,Object>();
?????? for(int i = 0; i < 100000; i++){
??? ?? map.put(String.valueOf(i), "java");
?????? }
?????? long startTime = System.currentTimeMillis();
?????? Set<Entry<String,Object>> entrySet = map.entrySet();
?????? for(Entry<String, Object> entry : entrySet){
??? ??? String key = entry.getKey();
??? ??? Object value = entry.getValue();
??? ??? System.out.println("key: " +key+ "? value:" + value);
?????? }
?????? long endTime = System.currentTimeMillis();
?????? System.out.println("===============================entrySet:"+(endTime-startTime));
??????
??????
?????? Map<String, Object> map1 = new HashMap<String,Object>();
?????? for(int i = 0; i < 100000; i++){
???? ?? map1.put(String.valueOf(i), "sun");
??????? }
?????? long start = System.currentTimeMillis();
?????? Set<String> keySet = map1.keySet();
?????? Iterator<String> it = keySet.iterator();
?????? while(it.hasNext()){
??? ??? String key = it.next();
??? ??? Object value = map1.get(key);
??? ??? System.out.println("key: " + key +"? value: " + value);
?????? }
?????? long end = System.currentTimeMillis();
?????? System.out.println("=================================keySet:" + (end-start));
?? }
}