Java实验5 IO流 第四题

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设计学生类Student，属性：学号（整型）；姓名（字符串），选修课程（名称）及课程成绩（整型）。编写一个控制台程序，能够实现Student信息的保存、读取。具体要求：（1）提供Student信息的保存功能：通过控制台输入若干个学生的学号、姓名以及每个学生所修课程的课程名和成绩，将其信息保存到data.dat中；（2）数据读取显示：能够从data.dat文件中读取学生及其课程成绩并显示于控制台。

import java.io.*;
import java.util.*;
public class Student {
	private int no;
	private String name;
	private String subject;
	private int score;
	public int getNo() {
		return no;
	}
	public void setNo(int no) {
		this.no = no;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getSubject() {
		return subject;
	}
	public void setSubject(String subject) {
		this.subject = subject;
	}
	public int getScore() {
		return score;
	}
	public void setScore(int score) {
		this.score = score;
	}
	@Override
	public String toString() {
		return "Student [no=" + no + ", name=" + name + ", subject=" + subject + ", score=" + score + "]";
	}
	public static void saveStudent(List<Student> students) throws IOException {
		try {
			BufferedWriter out=new BufferedWriter(new FileWriter("data.dat",true));
			StringBuffer s=new StringBuffer();
			for(int i=0;i<students.size();i++) {
				Student stu=students.get(i);
				s.append(stu.getNo()+"#"+stu.getName()+"#"+stu.getSubject()+"#"+stu.getScore());
				out.write(s.toString());
				out.write("\n");
			}
			out.flush();
			out.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
	}
	public static List<Student> readStudent(String filename) throws IOException{
		File file=new File(filename);
		List<Student> data=new ArrayList<Student>();
		if(file.exists()) {	
			BufferedReader in=new BufferedReader(new InputStreamReader(new FileInputStream(file)));
			String s=null;
			String[] str=null;
			while(true) {
				s=in.readLine();
				if(s!=null) {
					Student stu=new Student();
					str=s.split("#");
					stu.setNo(Integer.parseInt(str[0]));
					stu.setName(str[1]);
					stu.setSubject(str[2]);
					stu.setScore(Integer.parseInt(str[3]));
					data.add(stu);
				}
				else break;
			}
			in.close();
		}
		return data;
	}
	public static void show() {
		System.out.println("退出请输入#0");
		System.out.println("录入学生信息请输入#1");
		System.out.println("查看学生信息请输入#2");
		System.out.println("保存学生信息请输入#3");
	}
}

import java.io.IOException;
import java.util.*;
public class Main {

	public static void main(String[] args) throws IOException {
		Scanner scan=new Scanner(System.in);
		List<Student>data=new ArrayList<Student>();
		Student.show();
		Student stu=new Student();
		while(true) {
			String s=scan.next();
			if(s.equals("#0")) {
				System.out.println("已退出输入");
				break;
			}
			else if(s.equals("#1")) {
				String temp=null;
				System.out.println("请依次“输入学号#姓名#选修课程#课程成绩”");
				while(true) {
					System.out.print("学号：");
					int No=scan.nextInt();
					stu.setNo(No);
					System.out.print("姓名：");
					String Name=scan.next();
					stu.setName(Name);
					System.out.print("选修课程：");
					String Sub=scan.next();
					stu.setSubject(Sub);
					System.out.print("课程成绩：");
					int Score=scan.nextInt();
					stu.setScore(Score);
					data.add(stu);
					System.out.println("输入exit结束录入，输入其他继续录入");
					temp=scan.next();
					if(temp.equals("exit")) {
						System.out.println("已退出录入");
						break;
					}
				}
			}
			else if(s.equals("#2")) {
				List<Student> stus=Student.readStudent("data.dat");
				if(stus==null||stus.size()==0) {
					System.out.println("无学生信息！");
				}else {
					for(int i=0;i<stus.size();i++) {
						System.out.println(stus.get(i).toString());
					}
				}
			}
			else if(s.equals("#3")) {
				if(data.size()>0) {
					Student.saveStudent(data);
                                        data.clear();
					System.out.println("信息已保存");
				}else {
					System.out.println("无需要保存的学生信息！");
				}
			}
			else {
				System.out.println("指令错误！");
				Student.show();
			}
		}
		scan.close();
	}
}