Java实验5 IO流第四题

梦里梦外; 2022-04-13 09:48 164阅读 0赞

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();
    	}
    }