Now let's take the example of a comparator as an example: ComparableTest.java.
Import java.util.ArrayList;
Import java.util.collections;
Import java.util.comparator;
Common class comparison test {
Public static void main(String[] args) {
Comparator & lt student & gt comparator = new comparator & lt student & gt(){
Public int compare (student s 1, student s2) {
//Age is preferred
if(s 1.age！ =s2.age){
Returns s1.age-s2.age;
}
Otherwise {
//Sort by name of the same age.
If (! s 1 . name . equals(S2 . name)){
Return s1.name.compareto (s2.name);
}
Otherwise {
//If the names are the same, sort by student number.
Returns s1.id-s2.id;
}
}
}
};
Stu 1 = freshman (1, "Zhang San", "Male", 28, "CS");
Stu2 = freshman (2, "Li Si", "female", 19, "CS");
Stu3 = new student (3, "King of Wu", "Male", 22, "CS");
Stu4 = freshman (4, "Liu Zhao", "female", 17, "CS");
Stu5 = freshman (5, "first name", "male", 22, "CS");
ArrayList & lt student & gtList = new ArrayList & lt student & gt ();
list . add(stu 1)；
list . add(stu 2)；
list . add(stu 3)；
list . add(stu 4)；
list . add(stu 5)；
//This will be sorted automatically according to the rules.
Collections.sort(List，comparator)；
To display (a list);
}
Static void display (ArrayList & lt student & gt lst) (
For (student: first place)
system . out . println(s)；
}
}
Class students {
int age
int id
String gender;
String name;
String cs;
Student (integer id, string name, string gender, integer age, string cs){
This.age = age;
this.name = name
This.gender = gender;
this.id = id
this.cs = cs
}
Common string toString(){
Return id+" "+ name+""+gender+""+age+""+CS;
}
}