遍历3方式

Posted 2021-01-02 mj5714

 1 package Z3_1;
 2 
 3 import java.util.*;
 4 
 5 public class QWE {
 6 public static void main(String[] args) {
 7     Map mijia=new HashMap();
 8     mijia.put("cn", "china");
 9     mijia.put("uk", "ufo");
10     //方式一    增强for
11     System.out.println("方式一增强for");
12     Set ks=mijia.keySet();//keyset
13     for (Object object : ks) {
14         System.out.println(mijia.get(object));
15     }
16     //方式二    迭代器Iterator
17     System.out.println("方式二，迭代器Iteration");
18     Iterator it=ks.iterator();
19     while(it.hasNext()){
20         String sk=(String)it.next();
21         System.out.println(sk+"=="+mijia.get(sk));
22     }
23     
24 
25 //    Set set =mapContries.entrySte();
26 //    for (Object object : set) {
27 //        Map.Entryentry=(Map.Entry);
28 //        entry.getKey();//String
29 //        entry.getValue();
30 //    }
31     
32     
33     
34 //    //遍历方式三 
35     Dog dog1=new Dog("mijia","5714");
36     Dog dog2=new Dog("qwe","123");
37     Dog dog3=new Dog("sad","456");
38     Dog []dogg=new Dog[3];
39     
40     HashMap hm=new HashMap<>();
41     hm.put(1, dog1);
42     hm.put(2, dog2);
43     hm.put(3, dog3);
44     Set set =hm.entrySet();
45     Iterator itt=set.iterator();
46     while(itt.hasNext())
47     {
48         Map.Entry en=(Map.Entry)itt.next();
49         Dog dog =(Dog)en.getValue();
50         System.out.println(en.getKey()+" "+en.getValue());
51     }
52 }
53 }