处理文件读写异常：Java代码示例

原创骑猪看日落 2024-10-16 19:48 77阅读 0赞

在Java中，处理文件读写异常通常使用try-catch语句。以下是一些代码示例：

1. 文件读取异常：
```java
import java.io.File;
import java.io.IOException;

public class FileReaderException {
    public static void main(String[] args) {
        File file = new File("non_existent_file.txt"); // 一个不存在的文件

try {
            // 尝试读取文件
            String content = readFile(file);
            System.out.println(content);
        } catch (IOException e) {
            // 处理读取异常
            System.err.println("Error occurred while reading file: " + e.getMessage());
            e.printStackTrace();
        }
    }

private static String readFile(File file) throws IOException {
        if (!file.exists()) { throw new FileNotFoundException(file.getAbsolutePath() + ": File does not exist!"); } else if (!file.canRead()) { throw new IllegalAccessException(file.getAbsolutePath() + ": Permission denied!"); }

try (BufferedReader br = new BufferedReader(new FileReader(file)))) {
            StringBuilder contentBuilder = new StringBuilder();
            String line;

while ((line = br.readLine())) != null) {
                contentBuilder.append(line).append("\n");
            }

return contentBuilder.toString();
        }
    }
}
```
2. 文件写入异常：
```java
import java.io.File;
import java.io.IOException;
import java.util.Random;

public class FileWriterException {
    public static void main(String[] args) {
        File file = new File("temp_file.txt"); // 创建一个临时文件

try {
            // 生成随机内容
            String content = generateRandomContent(100);
            
            // 尝试写入文件
            writeFile(file, content);
            
            System.out.println("File written successfully!");
        } catch (IOException e) {
            // 处理写入异常
            System.err.println("Error occurred while writing file: " + e.getMessage());
            e.printStackTrace();
        }
    }

private static String generateRandomContent(int length) {
        StringBuilder contentBuilder = new StringBuilder();
        Random randomGenerator = new Random();

for (int i = 0; i < length; i++) {
            int randomNumber = randomGenerator.nextInt(128)); // 生成一个0-127的随机数
            char randomChar = (char) randomNumber; // 将随机数转换为字符

contentBuilder.append(randomChar).append(" ");
        }
        
        return contentBuilder.toString().trim(); // 去除末尾多余的空格
    }

private static void writeFile(File file, String content) throws IOException {
        try (BufferedWriter writer = new BufferedWriter(new FileWriter(file)))) {
            writer.write(content);
            System.out.println("Content written successfully!");
        } catch (IOException e) {
            throw new IOException("Error occurred while writing to file: " + e.getMessage(), e);
        }
    }
}
```
以上代码示例中，`readFile()`方法用于尝试读取文件内容，如果文件不存在或者权限不足，会抛出相应的`IOException`。`writeFile()`方法则负责将内容写入文件，同样可能抛出`IOException`。