Lære Handling Errors | Java File I/O Essentials

When working with file input and output in Java, you must be prepared to handle situations where things do not go as planned. Java uses a system of checked exceptions to help you manage errors that can occur during file operations. Two of the most common exceptions you will encounter are IOException and FileNotFoundException. A checked exception is a type of exception that the Java compiler requires you to handle, either by catching it with a try-catch block or by declaring it in your method signature.

IOException is a general exception that covers many input and output errors, such as problems reading from or writing to a file. FileNotFoundException is a more specific exception that occurs when you try to open a file that does not exist or the file path is incorrect. By using try-catch blocks, you can catch these exceptions and respond to them gracefully, such as by showing a helpful error message to the user instead of letting your program crash.


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import java.io.FileReader;
import java.io.FileNotFoundException;
import java.io.IOException;

public class ReadFileExample {
    public static void main(String[] args) {
        try {
            FileReader reader = new FileReader("data.txt");
            int character;
            while ((character = reader.read()) != -1) {
                System.out.print((char) character);
            }
            reader.close();
        } catch (FileNotFoundException e) {
            System.out.println("Error: The file was not found.");
        } catch (IOException e) {
            System.out.println("Error: An I/O error occurred.");
        }
    }
}

Handling errors is a crucial part of writing reliable programs. By anticipating and catching exceptions like IOException and FileNotFoundException, you prevent your program from crashing unexpectedly and provide a better experience for your users. Proper error handling ensures your applications are robust and user-friendly, even when something goes wrong during file operations.

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              1234567891011121314151617181920
            
import java.io.FileReader;
import java.io.FileNotFoundException;
import java.io.IOException;

public class ReadFileExample {
    public static void main(String[] args) {
        try {
            FileReader reader = new FileReader("data.txt");
            int character;
            while ((character = reader.read()) != -1) {
                System.out.print((char) character);
            }
            reader.close();
        } catch (FileNotFoundException e) {
            System.out.println("Error: The file was not found.");
        } catch (IOException e) {
            System.out.println("Error: An I/O error occurred.");
        }
    }
}

Alt var klart?

Takk for tilbakemeldingene dine!

Seksjon 1. Kapittel 7