Javatry-catch-finally异常处理全解析

import java.io.*;

public class FileReadExample {
    public static void main(String[] args) {
        FileReader fileReader = null;
        BufferedReader bufferedReader = null;

        try {
            fileReader = new FileReader("data.txt");
            bufferedReader = new BufferedReader(fileReader);
            String line;
            while ((line = bufferedReader.readLine()) != null) {
                System.out.println(line);
            }
        } catch (FileNotFoundException e) {
            System.err.println("文件未找到：" + e.getMessage());
        } catch (IOException e) {
            System.err.println("读取文件时出错：" + e.getMessage());
        } finally {
            // 确保资源被释放
            try {
                if (bufferedReader != null) {
                    bufferedReader.close();
                }
                if (fileReader != null) {
                    fileReader.close();
                }
            } catch (IOException e) {
                System.err.println("关闭资源时出错：" + e.getMessage());
            }
        }
    }
}

import java.io.*;

public class TryWithResourcesExample {
    public static void main(String[] args) {
        try (FileReader fileReader = new FileReader("data.txt");
             BufferedReader bufferedReader = new BufferedReader(fileReader)) {

            String line;
            while ((line = bufferedReader.readLine()) != null) {
                System.out.println(line);
            }

        } catch (FileNotFoundException e) {
            System.err.println("文件未找到：" + e.getMessage());
        } catch (IOException e) {
            System.err.println("读写异常：" + e.getMessage());
        }
        // 资源会自动关闭，无需 finally 块
    }
}

public static int testFinallyReturn() {
    try {
        return 1;
    } finally {
        System.out.println("finally 块仍会执行");
    }
}