java - java中的文件问题

Question

我创建了一个类来存储和检索文件中的数据，但是当我运行代码时，我遇到了错误，例如

Error retrieving infojava.io.FileNotFoundException: computer-db.txt (The system cannot find the file specified)
java.io.FileNotFoundException: computer-db.txt (The system cannot find the file specified)
at java.io.FileInputStream.open0(Native Method)
at java.io.FileInputStream.open(Unknown Source)
at java.io.FileInputStream.<init>(Unknown Source)
at java.util.Scanner.<init>(Unknown Source)
at testing.Driver.retrieve(Driver.java:63)
at testing.Driver.main(Driver.java:19)
java.lang.NullPointerException
at testing.Driver.retrieve(Driver.java:89)
at testing.Driver.main(Driver.java:19)

每当我运行它时，这都会显示在控制台输出中。我还意识到，当我运行程序时，并未创建该文件

这是我编写的用于存储和读取文件的驱动程序文件

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

public class Driver {

    public static void main(String[] args) {        
        Computer c1=new Computer();
        c1.display();   

        Computer p=new Computer();
        try {
            p=retrieve();
        } catch (Exception e) {
            e.printStackTrace();
        }
        p.display();

    }

    public static void store(Computer c) throws IOException {
        FileWriter pc=new FileWriter("computer-db.txt");
        try {
            pc.write(c.getOwnername()+"\t");
            pc.write(c.getModel()+"\t");
            pc.write(c.getColor()+"\t");
            pc.write(c.getCentralprocessingunit().getClockspeed()+"\t");
            pc.write(c.getCentralprocessingunit().getManufacturer()+"\t");
            pc.write(c.getCentralprocessingunit().getNumcores()+"\n");
        } catch(IOException ex) {
            System.out.println("error writing to the file "+ex);
        } finally {
            try {
                if(pc != null) {
                    pc.close();
                }
            } catch(IOException ex) {
                System.out.println("Error with file "+ex);
            }
        }           
    }

    public static Computer retrieve()throws Exception {
        Scanner read=new Scanner(System.in);
        Scanner rfile= null;
        Computer pc=new Computer();
        try {
            rfile=new Scanner(new File("computer-db.txt"));
            System.out.println("Enter the name to search for: ");
            String srcParam = read.next();
            while(rfile.hasNext()) {
                String ownername=rfile.next();
                String model=rfile.next();
                String color=rfile.next();
                double clockspeed=rfile.nextDouble();
                String manufacturer=rfile.next();
                int numcores=rfile.nextInt();

                if(ownername.equals(srcParam)) {
                    pc = new Computer(ownername,model,color,clockspeed,
                        manufacturer,numcores);
                    break;
                }
            }
        } catch(IOException ex) {
            System.out.println("Error retrieving info"+ex);
            ex.printStackTrace();
        } finally {
            rfile.close();
            read.close();
        }
        return pc;
    }
}

有谁知道如何解决这个问题吗？任何帮助将不胜感激。

Answer 1

FileNotFoundException 告诉您该文件不存在。您正在尝试打开当前目录中的 computer-db.txt。文件真的存在吗？