22.Collections sorting

 Packageentity; Public classStudentImplementscomparable{Private intnumber=0;//School Number    PrivateString name= "";//Student Name    PrivateString gender= "";//Sex     Public intGetNumber () {returnNumber ; }     Public voidSetnumber (intNumber ) {         This. number=Number ; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. name=name; }     PublicString Getgender () {returngender; }     Public voidSetgender (String gender) { This. gender=gender; }     Public intcompareTo (Object obj) {Student Student=(Student) obj; if( This. number==Student.number) {              return0;//If the study number is the same, then the two are equal.}Else if( This.number>Student.getnumber ()) {             return1;//If the student's number is greater than the number of incoming students}Else{             return-1;//If the student's number is less than that of the incoming student ,        }    }}

 Packagetest;Importjava.util.ArrayList;Importjava.util.Collections;ImportJava.util.Iterator;Importentity. Student; Public classCollectionsdemo { Public Static voidMain (string[] args) {Student student1=NewStudent (); Student1.setnumber (5); Student Student2=NewStudent (); Student2.setnumber (2); Student Student3=NewStudent (); Student3.setnumber (1); Student Student4=NewStudent (); Student4.setnumber (4); ArrayList<Student> list=NewArraylist<student>();        List.add (STUDENT1);        List.add (Student2);        List.add (STUDENT3);        List.add (STUDENT4); System.out.println ("--------------before sorting"); Iterator<Student> iterator=List.iterator ();  while(Iterator.hasnext ()) {Student Stu=Iterator.next ();        System.out.println (Stu.getnumber ()); }        //sort list by using the Sort method of collectionsSystem.out.println ("--------------after sorting");         Collections.sort (list); Iterator=List.iterator ();  while(Iterator.hasnext ()) {Student Stu=Iterator.next ();        System.out.println (Stu.getnumber ()); }     }}

22.Collections sorting