The method of sorting the list collection in Java the use of the comparator is sorted according to the sum of the Chinese English scores of the students ' object sequence

 PackageCom.swift;Importjava.util.ArrayList;Importjava.util.Collections;ImportJava.util.Comparator;Importjava.util.List;ImportJava.util.Scanner; Public classtest2_objectio {@SuppressWarnings ("Unchecked")     Public Static voidMain (string[] args) {/** 2nd: There are five students, each student has 3 courses (Chinese, maths, English) scores, write a program to receive information from the keyboard input students, * The input format is: name,30,30,30 (name, three lessons), and then the input of the student information according to the total score from the high         To a low order written to a name "Stu.txt" file.         * Requirements: Stu.txt file format to be more intuitive, open this file, you can see the student's information very clearly. */List<Student> list =NewArraylist<student>(); Scanner Scan=NewScanner (system.in);  for(inti = 1; I <=5; i++) {System.out.println ("Please enter" +i+ "Student Information: format name 60 60 60"); String name=Scan.next (); Float Yuwen=scan.nextfloat (); Float Shuxue=scan.nextfloat (); Float Yingyu=scan.nextfloat (); Student Stu=NewStudent (name, Yuwen, Shuxue, Yingyu);        List.add (Stu); }                 for(Student stu:list) {System.out.println (stu.tostring ()); } collections.sort (List,NewComparator<student>() {@Override Public intCompare (Student O1, Student O2) {floatNum= (O2.getshuxue () +o2.getyingyu () +o2.getyuwen ())-(O1.getshuxue () +o1.getyingyu () +O1.getyuwen ()); intI= (int) num; returni;                }        });  for(Student stu:list) {System.out.println (stu.tostring ()); }    }}classStudent {PrivateString name; Private floatYuwen; Private floatShuxue; Private floatYingyu;  PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }     Public floatGetyuwen () {returnYuwen; }     Public voidSetyuwen (floatYuwen) {         This. Yuwen =Yuwen; }     Public floatGetshuxue () {returnShuxue; }     Public voidSetshuxue (floatShuxue) {         This. Shuxue =Shuxue; }     Public floatGetyingyu () {returnYingyu; }     Public voidSetyingyu (floatYingyu) {         This. Yingyu =Yingyu; }     PublicStudent (String name,floatYuwen,floatShuxue,floatYingyu) {        Super();  This. Name =name;  This. Yuwen =Yuwen;  This. Shuxue =Shuxue;  This. Yingyu =Yingyu; }     PublicStudent () {Super(); } @Override PublicString toString () {return"Student [name=" + name + ", yuwen=" + Yuwen + ", shuxue=" + Shuxue + ", yingyu=" + Yingyu + "]"; }}

The comparator is an anonymous inner class, Collections.sort (List,comparator<student> () {});

The Compare method is then implemented, returning a value of type int, positive negative 0 representing greater than or equal to

Add the content code of IO stream as follows;

 PackageCom.swift;ImportJava.io.BufferedWriter;ImportJava.io.File;Importjava.io.FileNotFoundException;ImportJava.io.FileOutputStream;Importjava.io.IOException;ImportJava.io.OutputStreamWriter;Importjava.io.UnsupportedEncodingException;Importjava.util.ArrayList;Importjava.util.Collections;ImportJava.util.Comparator;Importjava.util.List;ImportJava.util.Scanner; Public classtest2_objectio {@SuppressWarnings ("Unchecked")     Public Static voidMain (string[] args) {/** 2nd: There are five students, each student has 3 courses (Chinese, maths, English) scores, write a program to receive information from the keyboard input students, * The input format is: name,30,30,30 (name, three lessons), and then the input of the student information according to the total score from the high         To a low order written to a name "Stu.txt" file.         * Requirements: Stu.txt file format to be more intuitive, open this file, you can see the student's information very clearly. */List<Student> list =initiatelist ();  for(Student stu:list) {System.out.println (stu.tostring ()); } collections.sort (List,NewComparator<student>() {@Override Public intCompare (Student O1, Student O2) {floatNum= (O2.getshuxue () +o2.getyingyu () +o2.getyuwen ())-(O1.getshuxue () +o1.getyingyu () +O1.getyuwen ()); intI= (int) num; returni;                }        });                    Initiate_io (list); }    Private Static voidInitiate_io (list<student>list)        {BufferedWriter bw; StringBuffer SB=NewStringBuffer ();  for(Student stu:list) {sb.append (stu.tostring ()); Sb.append ("\ r \ n"); }        Try{BW=NewBufferedWriter (NewOutputStreamWriter (NewFileOutputStream ("Src\\stu.txt"), "Utf-8");//need to indicate pathBw.write (sb.tostring ());        Bw.flush (); } Catch(unsupportedencodingexception e) {e.printstacktrace (); } Catch(FileNotFoundException e) {e.printstacktrace (); } Catch(IOException e) {e.printstacktrace (); }             }    Private StaticList<student>initiatelist () {List<Student> list =NewArraylist<student>(); Scanner Scan=NewScanner (system.in);  for(inti = 1; I <=5; i++) {System.out.println ("Please enter" +i+ "Student Information: format name 60 60 60"); String name=Scan.next (); Float Yuwen=scan.nextfloat (); Float Shuxue=scan.nextfloat (); Float Yingyu=scan.nextfloat (); Student Stu=NewStudent (name, Yuwen, Shuxue, Yingyu);        List.add (Stu); }        returnlist; }}classStudent {PrivateString name; Private floatYuwen; Private floatShuxue; Private floatYingyu;  PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }     Public floatGetyuwen () {returnYuwen; }     Public voidSetyuwen (floatYuwen) {         This. Yuwen =Yuwen; }     Public floatGetshuxue () {returnShuxue; }     Public voidSetshuxue (floatShuxue) {         This. Shuxue =Shuxue; }     Public floatGetyingyu () {returnYingyu; }     Public voidSetyingyu (floatYingyu) {         This. Yingyu =Yingyu; }     PublicStudent (String name,floatYuwen,floatShuxue,floatYingyu) {        Super();  This. Name =name;  This. Yuwen =Yuwen;  This. Shuxue =Shuxue;  This. Yingyu =Yingyu; }     PublicStudent () {Super(); } @Override PublicString toString () {return"Student [name=" + name + ", yuwen=" + Yuwen + ", shuxue=" + Shuxue + ", yingyu=" + Yingyu + "]"; }}

The method of sorting the list collection in Java the use of the comparator is sorted according to the sum of the Chinese English scores of the students ' object sequence