Two ways to sort Java list (implement comparable interface and Collections.sort overloaded methods)

Reprinted from: http://blog.csdn.net/zxy_snow/article/details/7232035

There are two ways to sort list by using the Collections.sort method

The first is that the object in the list implements the comparable interface, as follows:

/*** Sort the user according to order*/   Public classUserImplementsComparable<user>{       PrivateString name; PrivateInteger Order;  PublicString GetName () {returnname; }        Public voidsetName (String name) { This. Name =name; }        PublicInteger GetOrder () {returnorder; }        Public voidSetorder (Integer order) { This. Order =order; }        Public intcompareTo (User arg0) {return  This. GetOrder (). CompareTo (Arg0.getorder ()); }} Test: Public classtest{ Public Static voidMain (string[] args) {User user1=NewUser (); User1.setname (A); User1.setorder (1); User User2=NewUser (); User2.setname ("B"); User2.setorder (2); List<User> list =NewArraylist<user>(); //add User2 and add user1 hereList.add (User2);           List.add (user1);           Collections.sort (list);  for(User u:list) {System.out.println (U.getname ()); }       }   }   

The output is as follows
A
B

The second method is implemented according to the Collections.sort overloaded method, for example:

[Java] View plain copy/*** Sort the user according to order*/   Public classUser {//no need to implement comparable interface here    PrivateString name; PrivateInteger Order;  PublicString GetName () {returnname; }        Public voidsetName (String name) { This. Name =name; }        PublicInteger GetOrder () {returnorder; }        Public voidSetorder (Integer order) { This. Order =order; }} This can be written in the main class (hastset-->List-->sort): Public classTest { Public Static voidMain (string[] args) {User user1=NewUser (); User1.setname (A); User1.setprice (11); User User2=NewUser (); User2.setname ("B"); User2.setprice (2); Set<User> Hset =NewHashset<user>();          Hset.add (User2);            Hset.add (user1); List<User> list =NewArraylist<user>();              List.addall (Hset); Collections.sort (list,NewComparator<user>(){               Public intCompare (user arg0, user arg1) {returnArg0.getprice (). CompareTo (Arg1.getprice ());          }          });  for(User u:list) {System.out.println (U.getname ()); }      }  

The output results are as follows:

A
B

The default is ascending, which will.    Return Arg0.getorder (). CompareTo (Arg1.getorder ()); Switch
Return Arg1.getorder (). CompareTo (Arg0.getorder ());
It's in descending order.

Two ways to sort Java list (implement comparable interface and Collections.sort overloaded methods)