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Collection (object) sorting

巴扎黑
巴扎黑Original
2016-12-10 09:22:001646browse

There are two ways to sort the list using the Collections.sort method
The first is that the objects in the list implement the Comparable interface, as follows:
[java] view plain copy
/**
* Sort Users according to order
*/
public class User implements Comparable< ;User>{
       private String name;                                                                                      ;
}
public Integer getOrder( ) {
              return order;                                                                                                                             , return this.getOrder().compareTo(arg0.getOrder() ; user1.setOrder "
             //This Add user2 and then add user1
        list.add(user2);  
          list.add(user1);  
          Collections.sort(list); (u.getName( ); #&*/BPublic class user {// here No need to implement the comparable interface
Private String name;
Private Integer Order; V PUBLIC VOID SETNAME (String name) {
this.name = name;
}
public Integer getOrder() {
return order;
}
public void setOrder(Integer order) {
this.order = order;
}
}

Just write this in the main class (HastSet——>List——>sort to sort):
public class Test {
public static void main(String[] args) {
User user1 = new User();
user1.setName("a" ;
        Set Hset = new HashSet();              Hset.add(user2); ;User>();
list. addAll(Hset);


Collections.sort(list,new Comparator(){
            public int compare(User arg0, User arg1) {                            .compareTo(arg1.getPrice()) ;


The output results are as follows:
a
b

The default is ascending order ,Will. return arg0.getOrder().compareTo(arg1.getOrder()); Change to:
return arg1.getOrder().compareTo(arg0.getOrder());
It will be in descending order.

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