Java错误：默认构造函数无法处理异常类型FileNotFound异常 [英] Java error: Default constructor cannot handle exception type FileNotFound Exception

问题描述

我试图从一个文件中读取输入到一个Java小程序以显示为吃豆人的水平，但我需要使用类似于getLine（）...所以我搜索类似的东西，这是我发现的代码：

I'm trying to read input from a file to be taken into a Java applet to be displayed as a Pac-man level, but I need to use something similar to getLine()... So I searched for something similar, and this is the code I found:

File inFile = new File("textfile.txt");
FileInputStream fstream = new FileInputStream(inFile);//ERROR
// Get the object of DataInputStream
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));

我标记为ERROR的行给我一个错误，说默认构造函数无法处理异常类型FileNotFoundException

The line I marked "ERROR" gives me an error that says "Default constructor cannot handle exception type FileNotFoundException thrown by implicit super constructor. Must define an explicit constructor."

我搜索过这个错误信息，但我发现的一切似乎与我的情况无关。 / p>

I've searched for this error message, but everything I find seems to be unrelated to my situation.

推荐答案

在你的子类中声明一个显式构造函数，引发 FileNotFoundException ：

Either declare a explicit constructor at your subclass that throws FileNotFoundException:

public MySubClass() throws FileNotFoundException {
} 

或者使用 try-catch 代码块代替基础类中的代码，而不是抛出 FileNotFoundException exception：

Or surround the code in your base class with a try-catch block instead of throwing a FileNotFoundException exception:

public MyBaseClass()  {
    FileInputStream fstream = null;
    try {
        File inFile = new File("textfile.txt");
        fstream = new FileInputStream(inFile);
        // Get the object of DataInputStream
        DataInputStream in = new DataInputStream(fstream);
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
        // Do something with the stream
    } catch (FileNotFoundException ex) {
        Logger.getLogger(this.getClass().getName()).log(Level.SEVERE, null, ex);
    } finally {
        try {
            // If you don't need the stream open after the constructor
            // else, remove that block but don't forget to close the 
            // stream after you are done with it
            fstream.close();
        } catch (IOException ex) {
            Logger.getLogger(this.getClass().getName()).log(Level.SEVERE, null, ex);
        }
    }  
} 

不相关，编写Java小程序，请记住，您需要对其进行签名以便执行IO操作。

Unrelated, but since you are coding a Java applet, remember that you will need to sign it in order to perform IO operations.

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