Sort the List in java

Mainly used: Collections. sort () method:

 

1. JavaBean -- Content. java:

1. PackageCom. hmw. listsort;
3. Public ClassContent {
5. Private LongKey;
7. PrivateString name;
9. PublicContent (LongKey, String name ){
10. This. Key = key;
11. This. Name = name;
12. }
14. Public LongGetKey (){
15. ReturnKey;
16. }
18. Public VoidSetKey (LongKey ){
19. This. Key = key;
20. }
22. PublicString getName (){
23. ReturnName;
24. }
26. Public VoidSetName (String name ){
27. This. Name = name;
28. }
29. }

2. Comparison class -- ContentComparator. java:

1. PackageCom. hmw. listsort;
3. ImportJava. util. Comparator;
5. Public ClassContentComparatorImplementsComparator <Content> {
6. Public IntCompare (Content o1, Content o2 ){
8. // Route null to the end
9. If(O1 =Null){
10. Return1;
11. }
12. If(O2 =Null|! (O2InstanceofContent )){
13. Return-1;
14. }
16. LongKey1 = o1.getKey ();
17. LongKey2 = o2.getKey ();
18. ReturnKey1> key2? 1: key1 <key2? -1: 0;
20. /*
21. // If You Want To sort by name field, you only need to change the last three lines of code to the following line.
22. Return o1.getName (). compareTo (o2.getName ());
23. */
24. }
25. }

 

 

3. Test class -- CompareClient. java

1. PackageCom. hmw. listsort;
3. ImportJava. util. ArrayList;
4. ImportJava. util. Collections;
5. ImportJava. util. List;
7. Public ClassCompareClient {
8. Public Static VoidMain (String [] args ){
9. List <content> List =NewArraylist <content> ();
10. List. Add (Null);
11. List. Add (NewContent (15000, "--- 15000 --"));
12. List. Add (NewContent (10000, "--- 10000 ---"));
13. List. Add (NewContent (20000, "--- 20000 ---"));
14. List. Add (Null);
15. List. Add (NewContent (25000, "--- 25000 ---"));
16. List. add (NewContent (13000, "--- 13000 ---"));
17. List. add (NewContent (15000, "--- 15000 ---"));
18. List. add (NewContent (89000, "--- 89000 ---"));
19. Collections. sort (list,NewContentComparator ());
21. /*
22. // Add this line of code in descending order.
23. Collections. reverse (list );
24. */
26. For(Content content: list ){
27. If(Content =Null){
28. System. out. println ("null ");
29. }Else{
30. System. out. println ("content. getName ()/t" + content. getName ());
31. }
32. }
33. }
34. }

 

The output result is as follows:

Content. getName () --- 10000 ---
Content. getName () --- 13000 ---
Content. getName () --- 15000 --
Content. getName () --- 15000 ---
Content. getName () --- 20000 ---
Content. getName () --- 25000 ---
Content. getName () --- 89000 ---
Null
Null