对其中某元素进行排序

 1 import java.util.ArrayList;
 2 import java.util.Collections;
 3 import java.util.Comparator;
 4 import java.util.List;
 5 
 6 public class test {
 7 
 8     /**
 9      * @param args
10      * @return
11      */
12 
13     public static void main(String[] args) {
14 
15         TuanInfo tuan1 = new TuanInfo();
16         tuan1.setAaa(2);
17         tuan1.setBuyer(2);
18         TuanInfo tuan2 = new TuanInfo();
19         tuan2.setAaa(1);
20         tuan2.setBuyer(1);
21         TuanInfo tuan3 = new TuanInfo();
22         tuan3.setAaa(3);
23         tuan3.setBuyer(3);
24         List<TuanInfo> list = new ArrayList<TuanInfo>();
25         list.add(tuan3);
26         list.add(tuan2);
27         list.add(tuan1);
28         for (TuanInfo t : list) {
29             System.out.println(t.getBuyer() + " " + t.getAaa());
30         }
31         Collections.sort(list, new BuyerCompare());
32         for (TuanInfo t : list) {
33             System.out.println(t.getBuyer() + " " + t.getAaa());
34         }
35 
36     }
37 }
38 
39 class TuanInfo {
40     int buyer;
41     int aaa;
42 
43     public int getBuyer() {
44         return buyer;
45     }
46 
47     public void setBuyer(int buyer) {
48         this.buyer = buyer;
49     }
50 
51     public int getAaa() {
52         return aaa;
53     }
54 
55     public void setAaa(int aaa) {
56         this.aaa = aaa;
57     }
58 
59 }
60 
61 class BuyerCompare implements Comparator<TuanInfo> {
62     public int compare(TuanInfo o1, TuanInfo o2) {
63         if (o1.getBuyer() > o2.getBuyer())
64             return -1;
65         else
66             return 1;
67     }
68 }