浅谈Java中Map和Set之间的关系(及Map.Entry)

package Demo;
import java.util.*;
import java.util.Map.*; 
public class DemoMap {
 public static void main(String[] args) {
 text1();
 System.out.println("=========================================================");
 text2();
 } 
 
 public static void text1(){
 Map<Integer,String> DemoMap=new HashMap<Integer,String>();
 DemoMap.put(4, "dddd");
 DemoMap.put(1, "a");
 DemoMap.put(3, "ccc");
 DemoMap.put(2, "bb");
 
 Collection<Map.Entry<Integer,String>> set=DemoMap.entrySet();
 System.out.println("set=="+set);
 
 Iterator<Map.Entry<Integer, String>> it=set.iterator();
 Map.Entry<Integer,String> entry;
 
 while(it.hasNext()){
 entry=it.next();
 System.out.println("en.getKey()=="+entry.getKey());
 System.out.println("en.getValue()=="+entry.getValue());
 }
 } 
 
 public static void text2(){
 Map<Integer,String> DemoMap=new LinkedHashMap<Integer,String>();
 DemoMap.put(4, "dddd");
 DemoMap.put(1, "a");
 DemoMap.put(3, "ccc");
 DemoMap.put(2, "bb"); 
 
 Iterator<Entry<Integer,String>> set=DemoMap.entrySet().iterator();
 Entry<Integer,String> temp;
 while(set.hasNext()){
 temp=set.next();
 System.out.println("getKey()=="+temp.getKey());
 System.out.println("getValue()=="+temp.getValue());
 } 
 } 
}