简单java程序

import java.io.BufferedReader;

import java.io.File;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.Iterator;

import java.util.TreeMap;

import com.linguofeng.dao.StudentDao;

import com.linguofeng.dao.impl.StudentDaoImpl;

import com.linguofeng.model.Student;

public class StudentMain {

    static StudentDao dao;

    static BufferedReader br;

    public static void main(String[] args) {

        /** 启动时判断数据文件是否存在,如不存在则新建. */

        File file = new File("student.dat");

        if (!file.exists()) {

            try {

                file.createNewFile();

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

        dao = new StudentDaoImpl();

        /** 获得控制台输入流 */

        br = new BufferedReader(new InputStreamReader(System.in));

        /** 进行死循环 */

        while (true) {

            System.out.println(getLine());

            System.out.println("=[0]主菜单\\\\\\=");

            System.out.println("=[1]查找学生\\\\\\=");

            System.out.println("=[2]增加学生\\\\\\=");

            System.out.println("=[3]删除一个学生\\\\\=");

            System.out.println("=[4]删除所有学生\\\\\=");

            System.out.println("=[5]学生列表\\\\\\=");

            System.out.println("=[6]更新学生\\\\\\=");

            System.out.println("=[x]退出\\\\\\=");

            System.out.println(getLine());

            System.out.print("请选择操作:");

            /** 获得控制台输入的内容 */

            String input = getInput();

            if (input.equals("")) {

                input = "x";

            }

            switch (input.charAt(0)) {

                case '2' :

                    addStu();

                    break;

                case 'x' :

                    System.out.println("退出成功,欢迎再次使用!");

                    System.exit(0);

                    break;

                case '5' :

                    findAll();

                    break;

                case '4' :

                    delAll();

                    break;

                case '3' :

                    delByNum();

                    break;

                case '1' :

                    findByNum();

                    break;

                case '6' :

                    updateByNum();

                    break;

                default :

                    System.out.println("不支持的系统指令,请重新输入!");

                    break;

            }

        }

    }

    /**

     * 根据学生学号查询学生对象信息

     */

    public static void findByNum() {

        System.out.print("请输入要查询的学生学号:");

        while (true) {

            String input = getInput();

            if (dao.findByNum(input) != null) {

                System.out.println(dao.findByNum(input));

                return;

            } else if (input.equals("")) {

                return;

            } else {

                System.out.print("查询失败,不存在该学生,请重新输入要删除的学生学号:");

            }

        }

    }

    /**

     * 根据学生学号删除学生对象

     */

    public static void delByNum() {

        System.out.println(getLine());

        findAll();/** 显示所有学生信息方便进行删除操作 */

        System.out.println(getLine());

        System.out.println("如需取消留空直接按回车.");

        System.out.print("请输入要删除的学生学号:");

        while (true) {

            String input = getInput();

            if (dao.delByNum(input)) {

                System.out.println("删除成功!");

                findAll();

                return;

            } else if (input.equals("")) {

                return;

            } else {

                System.out.print("删除失败,不存在该学生,请重新输入要删除的学生学号:");

            }

        }

    }

    /**

     * 学生列表

     */

    public static void findAll() {

     TreeMap stuMap = dao.findAll();

     Iterator iterator = stuMap.values().iterator();

        if (!iterator.hasNext()) {

            System.out.println("数据库为空");

        }

        while (iterator.hasNext()) {

            System.out.println(iterator.next());

        }

    }

    /**

     * 删除所有学生对象

     */

    public static void delAll() {

        while (true) {

            System.out.print("是否要删除所有学生信息,确定请输入YES,否请输入NO：");

            String input = getInput();

            if (input.equals("YES") || input.equals("yes")) {

                dao.delAll();

                System.out.println("清空成功");

                return;

            } else if (input.equals("NO") || input.equals("no")) {

                return;

            } else {

                System.out.println("输入有误,请重新输入!");

            }

        }

    }

    /**

     * 添加学生

     */

    public static void addStu() {

        while (true) {

            System.out.print("请输入要添加学生的个数:");

            String ch = null;

            try {

                ch = br.readLine();

            } catch (IOException e) {

                e.printStackTrace();

            }

            if (ch.equals("")) {

                System.out.println("输入有误,请重新输入!");

            } else {

                int size = Integer.parseInt(ch);

             TreeMap stuMap = new TreeMap();

             for (int i = 0; i < size; i++) {

                    Student student = new Student();

                    try {

                        System.out.print("请输入第 " + (i + 1) + " 个学生的姓名:");

                        student.setName(br.readLine());

                        System.out.print("请输入第 " + (i + 1) + " 个学生的学号:");

                        student.setNum(br.readLine());

                        System.out.print("请输入第 " + (i + 1)

                                + " 个学生的性别(男输:1;女输:0):");

                        student.setSex(Integer.parseInt(br.readLine()));

                    } catch (IOException e) {

                        e.printStackTrace();

                    }

                    stuMap.put(student.getNum(), student);

                }

                dao.addStu(stuMap);

                findAll();

                return;

            }

        }

    }

    public static void updateByNum() {

        findAll();

        System.out.print("请输入要修改的学生学号:");

        while (true) {

            String input = getInput();

            String num = input;

            Student student = dao.findByNum(num);

            if (student != null) {

                System.out.println(student);

                System.out.println("如不修改直接留空按回车!");

                System.out.print("请输入学生的新姓名:");

                input = getInput();

                if (!input.equals(""))

                    student.setName(input);

                System.out.print("请输入学生的新学号:");

                input = getInput();

                if (!input.equals(""))

                    student.setNum(input);

                System.out.print("请输入学生的新版性别(男输:1;女输:0):");

                input = getInput();

                if (!input.equals(""))

                    student.setSex(Integer.parseInt(input));

                dao.updateByNum(num, student);

                System.out.println("更新成功,更新后的数据:");

                System.out.println(dao.findByNum(student.getNum()));

                return;

            } else if (input.equals("")) {

                return;

            } else {

                System.out.print("查询失败,不存在该学生,请重新输入要修改的学生学号:");

            }

        }

    }

    public static void addTest() {

     TreeMap stuMap = new TreeMap();

     for (int i = 0; i < 10000; i++) {

            Student student = new Student(i, "A" + i, "NUM" + i, 0);

            stuMap.put(student.getNum(), student);

        }

        dao.addStu(stuMap);

        return;

    }

    /**

     * 获得===========分割符

     * 

     * @return

     */

    public static String getLine() {

        return "=========================================================";

    }

    /**

     * 获得控制台输入

     * 

     * @return

     */

    public static String getInput() {

        String ch = "";

        try {

            ch = br.readLine();

        } catch (IOException e) {

            e.printStackTrace();

        }

        return ch;

    }

}