新人求助编

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class Test0517 {
    class Student implements Comparable<Student> {
        String stuNo;
        String name;
        int score;
        public Student(String stuNo, String name, int score) {
            this.stuNo = stuNo;
            this.name = name;
            this.score = score;
        }
        @Override
        public String toString() {
            return stuNo +"\t" + name + "\t" + score;
        }
        @Override
        public int compareTo(Student o) {
            return score-o.score;
        }
    }
    private static final String ADD="0", DEL = "1", UPDATE="2",
            QUERY = "3", SORT = "4", SHOW="5", EXIT="-1";
    public static void main(String[] args) {
        Map<String, Test0517.Student> students = new LinkedHashMap<>();
        showMenu();
        Scanner scanner = new Scanner(System.in);
        String commandTxt = scanner.nextLine();
        while(!EXIT.equals(commandTxt)) {
            if(!Arrays.asList(EXIT, ADD, DEL, UPDATE, QUERY, SORT, SHOW).contains(commandTxt)) {
                System.out.println("命令有误:"+commandTxt);
            } else {
                executeMenu(commandTxt, scanner, students);
            }
            showMenu();
            commandTxt = scanner.nextLine();
        }
        scanner.close();
    }
    private static void executeMenu(String commandTxt, Scanner scanner, Map<String, Student> students) {
        if(ADD.equals(commandTxt)) {
            String no = getInputByMsg("学号:", scanner);
            String name = getInputByMsg("姓名:", scanner);
            String score = getInputByMsg("成绩:", scanner);
            while(!score.matches("\\d+")) {
                String flag = getInputByMsg("成绩必须是整数,不纠正则不添加,纠正:1,不纠正任意键继续", scanner);
                if("1".equals(flag)) {
                    score = getInputByMsg("成绩:", scanner);
                } else {
                    return;
                }
            }
            students.put(no, new Test0517().new Student(no, name, Integer.parseInt(score)));
        } else if(DEL.equals(commandTxt)) {
            String no = getInputByMsg("请输入要删除的学号:", scanner);
            if(!students.keySet().contains(no)) {
                System.out.println("学号" + no + "不存在,无删除操作");
            } else {
                students.remove(no);
            }
        } else if(UPDATE.equals(commandTxt)) {
            String no = getInputByMsg("请输入要修改的学号:", scanner);
            if(!students.keySet().contains(no)) {
                System.out.println("学号" + no + "不存在,无删除操作");
            } else {
                String name = getInputByMsg("姓名:", scanner);
                String score = getInputByMsg("成绩:", scanner);
                while(!score.matches("\\d+")) {
                    String flag = getInputByMsg("成绩必须是整数,不纠正则不修改,纠正:1,不纠正任意键继续", scanner);
                    if("1".equals(flag)) {
                        score = getInputByMsg("成绩:", scanner);
                    } else {
                        return;
                    }
                }
                students.put(no, new Test0517().new Student(no, name, Integer.parseInt(score)));
            }
        } else if(QUERY.equals(commandTxt)) {
            String no = getInputByMsg("请输入要查询的学号:", scanner);
            if(!students.keySet().contains(no)) {
                System.out.println("学号" + no + "不存在");
            } else {
                System.out.println(students.get(no));
            }
        } else if(SORT.equals(commandTxt)) {
            List<Student> tmpStus = new ArrayList<Student>(students.values());
            Collections.sort(tmpStus);
            students.clear();
            for(Student stu : tmpStus) students.put(stu.stuNo, stu);
        } else if(SHOW.equals(commandTxt)) {
            System.out.println("学号\t姓名\t成绩");
            for(Student stu : students.values()) {
                System.out.println(stu);
            }
        }
    }
    private static String getInputByMsg(String msg, Scanner scanner) {
        System.out.print(msg);
        return scanner.nextLine();
    }
    private static void showMenu() {
        System.out.println("=====================================");
        System.out.println("增加:0、删除:1、修改:2、查询:3、排序:4、输出:5");
        System.out.println("退出:-1");
        System.out.print("请输入指令:");
    }
}