JAVA学习笔记13：IO&类集

完成一个学生管理程序，使用学号作为键添加5个学生对象，并可以将全部的信息保存在文件中，可以实现对学生信息的学号查找、输出全部学生信息的功能。

import java.io.*;public class Student implements Serializable{private String name;private int age;public Student(String name,int age){this.setName(name);this.setAge(age);}public void setName(String name){this.name = name;}public void setAge(int age){this.age = age;}public String getName(){return this.name;}public int getAge(){return this.age;}public String toString(){return "姓名：" + this.getName() + "；年龄：" + this.getAge();}public boolean equals(Object obj){if (this==obj){return true;}if (!(obj instanceof Student)){return false;}Student stu = (Student)obj;if (this.getName().equals(stu.getName())&&this.getAge()==stu.getAge()){return true;}else{return false;}}public int hashCode(){return this.getName().hashCode()*this.getAge();}};

import java.io.*;public class FileOperate{private File f;public FileOperate(String path){this.f = new File(path);}public boolean store(Object obj) throws Exception{ObjectOutputStream oos = null;boolean flag = false;try{oos = new ObjectOutputStream(new FileOutputStream(this.f));oos.writeObject(obj);flag = true;}catch(Exception e){throw e;}finally{if (oos!=null){oos.close();}}return flag;}public Object load() throws Exception{ObjectInputStream ois = null;Object obj = null;try{if (!this.f.exists()){this.store(null);}ois = new ObjectInputStream(new FileInputStream(this.f));obj = ois.readObject();}catch(Exception e){throw e;}finally{if (ois!=null){ois.close();}}return obj;}};

import java.io.*;public class InputData{private static BufferedReader buf = new BufferedReader(new InputStreamReader(System.in));public static String getString(String info){String temp = null;System.out.print(info);try{temp = InputData.buf.readLine();}catch(IOException e){e.printStackTrace();}return temp;}public static int getInt(String info,String err){int temp = 0;boolean flag = true;String str = null;while (flag){str = InputData.getString(info);if (str.matches("^\\d+$")){temp = Integer.parseInt(str);flag = false;}else{System.out.println(err);}}return temp;}public static float getFloat(String info,String err){float temp = 0.0f;boolean flag = true;String str = null;while (flag){str = InputData.getString(info);if (str.matches("^\\d+\\.\\d+$")||str.matches("^\\d+$")){temp = Float.parseFloat(str);flag = false;}else{System.out.println(err);}}return temp;}};

import java.util.*;public class StuOperate{private FileOperate fo;private Map<String,Student> allStudent;@SuppressWarnings("unchecked")public StuOperate(String path){this.fo = new FileOperate(path);try{this.allStudent = (Map<String,Student>)this.fo.load();}catch(Exception e){e.printStackTrace();}if (this.allStudent==null){this.allStudent = new HashMap<String,Student>();}}public void add(){String number = null;while (true){number = InputData.getString("请输入学号<全为数字>：");if (number.matches("^\\d+$")){break;}else{System.out.println("学号不正确，请重新输入！");}}if (this.allStudent.containsKey(number)){while (true){String str = InputData.getString("系统已包含该学号的学生 ---> " + this.allStudent.get(number) + "，确定要覆盖？<Y/N>：");if (str.equalsIgnoreCase("n")){return;}else if(str.equalsIgnoreCase("y")){break;}else{System.out.println("输入不正确！");}}}String name = InputData.getString("请输入姓名：");int age = InputData.getInt("请输入年龄：","年龄必须为整数，请重新输入！");this.allStudent.put(number,new Student(name,age));try{this.fo.store(this.allStudent);}catch(Exception e){e.printStackTrace();}System.out.println("添加成功！");}public void remove(){String number = InputData.getString("请输入要删除的学生的学号：");if (this.allStudent.containsKey(number)){while (true){String str = InputData.getString("确定要删除该学生吗？<Y/N>：");if (str.equalsIgnoreCase("n")){return;}else if(str.equalsIgnoreCase("y")){break;}else{System.out.println("输入不正确！");}}this.allStudent.remove(number);try{this.fo.store(this.allStudent);}catch(Exception e){e.printStackTrace();}System.out.println("删除成功！");}else{System.out.println("系统不包含指定的学生信息！");}}public void search(){String number = InputData.getString("请输入要查询的学生的学号：");if (this.allStudent.containsKey(number)){System.out.println("学号：" + number + this.allStudent.get(number));}else{System.out.println("系统没有查询到指定学生的信息！");}}public void update(){String number = InputData.getString("请输入要更新信息的学生学号：");        if (this.allStudent.containsKey(number)){String name = InputData.getString("请设置姓名<原姓名:" + this.allStudent.get(number).getName()+">：");int age = InputData.getInt("请设置年龄<原年龄:" + this.allStudent.get(number).getAge()+">：","年龄必须为整数，请重新输入！");this.allStudent.put(number,new Student(name,age));try{this.fo.store(this.allStudent);}catch(Exception e){e.printStackTrace();}System.out.println("更新成功！");}else{System.out.println("系统不包含指定的学生信息！");}}public void clear(){while (true){String str = InputData.getString("确定要清空全部学生信息吗？<Y/N>：");if (str.equalsIgnoreCase("n")){return;}else if(str.equalsIgnoreCase("y")){break;}else{System.out.println("输入不正确！");}}this.allStudent.clear();try{this.fo.store(this.allStudent);}catch(Exception e){e.printStackTrace();}System.out.println("清空成功！");}public void findAll(){if (!this.allStudent.isEmpty()){this.printAll();}else{System.out.println("系统没有发现任何学生信息！");}}private void printAll(){Set<Map.Entry<String,Student>> allSet = this.allStudent.entrySet();Iterator<Map.Entry<String,Student>> iter = allSet.iterator();while (iter.hasNext()){Map.Entry<String,Student> me = iter.next();System.out.println("学号：" + me.getKey() + "；" + me.getValue());}}};

public class StuMenu{private StuOperate so;public StuMenu(String path){this.so = new StuOperate(path);while (true){this.show();}}public void show(){System.out.println("***学生管理系统***");System.out.println("【1】添加学生信息");System.out.println("【2】删除学生信息");System.out.println("【3】更新学生信息");System.out.println("【4】搜索学生信息");System.out.println("【5】查看全部信息");System.out.println("【6】清空全部信息");System.out.println("【0】退出系统\n");int i = InputData.getInt("请选择：","请输入正确的选项！");switch (i){case 1:{this.so.add();break;}case 2:{this.so.remove();break;}case 3:{this.so.update();break;}case 4:{this.so.search();break;}case 5:{this.so.findAll();break;}case 6:{this.so.clear();break;}case 0:{System.exit(1);break;}default:{System.out.println("请选择正确的操作！");break;}}}};

import java.io.*;public class StuManage{public static void main(String[] args){new StuMenu("d:" + File.separator + "student.dat");}};