Eclipse中未处理的异常类型IOException

Question

我使用Eclipse编写代码，在customHandler.saveTransactionToFile();处得到一个红色下划线，上面写着

未处理的exeption类型IOException。

为什么会发生这种情况，我该如何解决？

// Call method in customHandler class to write to file when button is pressed
public void actionPerformed(ActionEvent event)
{
    // Save transactions to file
    if(event.getSource()== buttonSaveTransaction)
    {
         customHandler.saveTransactionToFile();
    }
}
// Method in class customHandler that writes to file
public void saveTransactionToFile() throws IOException
{
    System.out.println("Skriver till fil");
    File outFile = new File("C:/JavaBank/" + selectedCustomerAccountNumber + ".data");
    FileOutputStream outFileStream = new FileOutputStream(outFile);
    PrintWriter outStream = new PrintWriter(outFileStream);
    outStream.println("test");
    outStream.close();  
}

Answer 1

由于saveTransactionToFile抛出异常，调用该方法的actionPerformed需要捕获并处理它。

public void actionPerformed(ActionEvent event)
{
    // Save transactions to file
    if(event.getSource()== buttonSaveTransaction)
    {
         try {
             customHandler.saveTransactionToFile();
         } catch(IOException e) { 
             // I broke, make sure you do something here, so the user
             // knows there was an error
         }
    }
}

请注意，您需要在此处（或在saveTransactionToFile中）处理异常。actionPerformed无法抛出已检查的异常。。。。

Answer 2

在actionPerformed（）方法内部，编写

customHandler.saveTransactionToFile();

像一样写

public void actionPerformed(ActionEvent event)
{
    // Save transactions to file
    if(event.getSource()== buttonSaveTransaction)
    {
        try
        {
            customHandler.saveTransactionToFile();
        }
        catch(IOException ioe)
        {
            ioe.printStackTrace();
        }
   }
}

要回答为什么必须这样做"这是因为被调用的方法，即customHandler.saveTransactionToFile();，已知会抛出定义中提到的IOException。"

希望这将有助于

问候

Answer 3

将其包围在try-catch 中

try
{
    if(event.getSource()== buttonSaveTransaction)
    {
         customHandler.saveTransactionToFile();
    }
}
catch(IOException e)
{
 //manage exception 
}

Answer 4

您可以使用它，也可以通过hvgotcodes查看答案。

try {
    customHandler.saveTransactionToFile();
} catch (IOException e) {
    e.printStackTrace();
}