在Java中出现两个单独的FileNotFoundException异常

Question

我需要两个单独的异常，一个是在缺少.pro文件时抛出，另一个是在缺少.cmd文件时抛出，当前设置会在任意一个文件缺失时抛出两个异常。请问我做错了什么？

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

import javax.xml.ws.Holder;

public class Inventory {

    static String FileSeparator = System.getProperty("file.separator");

    public static void main(String[] args) {
        String path = args[0];
        String name = args[1];
        ArrayList<Holder> because = new ArrayList<Holder>();

        try {
            File product = new File(path + name + ".pro");
            Scanner scan = new Scanner(product);
            while (scan.hasNext()) {
                System.out.print(scan.next());
            }
            scan.close();
        } catch (FileNotFoundException e) {
            System.out.println("Usage: java Inventory <path> <filename>");
            System.out.println("The products file \"" + name + ".pro\" does not exist.");
        }

        try {
            File command = new File(path + name + ".cmd");
            Scanner scan = new Scanner(command);

            while (scan.hasNext()) {
                System.out.println(scan.next());
            }
        } catch (FileNotFoundException f) {
            System.out.println("Usage: java Inventory <path> <filename>");
            System.out.println("The commands file \"" + name + ".cmd\" does not exist.");
        }

    }
}

- user2218030

---

可能是因为两者都缺失（或者你使用的路径在两种情况下都无效）？ - assylias

看起来如果两者中任意一个或两个都缺失，就会触发它们两个，将 return; 添加到第一个可以使只缺失 .pro 文件的测试工作，但 .cmd 文件仍会触发两个异常。 - user2218030

Answer 1

尝试像这样重构代码：

        File product = new File(path + name + ".pro");
        if (!product.exists()) {
            System.out.println("Usage: java Inventory <path> <filename>");
            System.out.println("The products file \"" + name + ".pro\" does not exist.");
            return;
        }

        File command = new File(path + name + ".cmd");
        if (!command.exists()) {
            System.out.println("Usage: java Inventory <path> <filename>");
            System.out.println("The commands file \"" + name + ".cmd\" does not exist.");
            return;
        }
        try {
            Scanner scan = new Scanner(product);
            while (scan.hasNext()) {
                System.out.print(scan.next());
            }
            scan.close();

            scan = new Scanner(command);
            while (scan.hasNext()) {
                System.out.println(scan.next());
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

- DiogoSantana

Answer 2

如果我将文件对象更改为以下内容，则对我有用：

File product = new File(path, name + ".pro");

- Beatty