对象排序有两种方式实现:
第一种:
实体类中实现Comparable接口,重写compareTo()方法,返回比较的值即可,这一种不常用,不灵活。
第二种:
package controllers.admin;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class AdminHandle{
public static void main(String[] args) {
List<Person> personList = new ArrayList<Person>();
personList.add(new Person("zhangsan",52)) ;
personList.add(new Person("lisi",30)) ;
personList.add(new Person("wangwu",33)) ;
personList.add(new Person("zhaoliu",41)) ;
personList.add(new Person("sunqi",33)) ;
Collections.sort(personList, new Comparator<Person>() {
@Override
public int compare(Person p1, Person p2) {
//return p1.age - p2.age; //年龄排序(倒序就反过来)
return p1.name.compareTo(p2.name) ; //字符串排序
}
});
System.out.println(personList);
}
}
class Person {
public String name ;
public int age ;
public Person(String name,int age){
this.name = name ;
this.age = age ;
}
public String toString(){
return "姓名:" + this.name + ";年龄:" + this.age ;
}
}
Set同理。