// 基类: InputStream 和 OutputStream

// 文件操作
FileInputStream fis = new FileInputStream("input.txt");
FileOutputStream fos = new FileOutputStream("output.txt");

// 示例：复制文件
try (FileInputStream fis = new FileInputStream("source.txt");
     FileOutputStream fos = new FileOutputStream("target.txt")) {
    byte[] buffer = new byte[1024];
    int len;
    while ((len = fis.read(buffer)) != -1) {
        fos.write(buffer, 0, len);
    }
}

// 缓冲流：提高读写效率
try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream("file.txt"));
     BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("copy.txt"))) {
    bis.transferTo(bos); // Java 9+
}

// 数据流：读写基本数据类型
try (DataOutputStream dos = new DataOutputStream(new FileOutputStream("data.bin"))) {
    dos.writeInt(100);
    dos.writeUTF("Hello");
    dos.writeDouble(3.14);
}

// 对象流：序列化和反序列化
class User implements Serializable {
    private String name;
    private int age;
}

// 写入对象
try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("user.obj"))) {
    User user = new User("张三", 25);
    oos.writeObject(user);
}

// 读取对象
try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream("user.obj"))) {
    User user = (User) ois.readObject();
}

// 基类: Reader 和 Writer

// 文件读写
try (FileReader fr = new FileReader("input.txt");
     FileWriter fw = new FileWriter("output.txt")) {
    char[] buffer = new char[1024];
    int len;
    while ((len = fr.read(buffer)) != -1) {
        fw.write(buffer, 0, len);
    }
}

// 缓冲字符流
try (BufferedReader br = new BufferedReader(new FileReader("file.txt"))) {
    String line;
    while ((line = br.readLine()) != null) {
        System.out.println(line);
    }
}

// 字符串读写
StringReader sr = new StringReader("Hello World");
StringWriter sw = new StringWriter();

// InputStreamReader：字节流转换为字符流
try (InputStreamReader isr = new InputStreamReader(new FileInputStream("file.txt"), "UTF-8")) {
    char[] buffer = new char[1024];
    int len;
    while ((len = isr.read(buffer)) != -1) {
        System.out.print(new String(buffer, 0, len));
    }
}

// OutputStreamWriter：字符流转换为字节流
try (OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("file.txt"), "UTF-8")) {
    osw.write("你好，世界");
}

try {
    // 可能抛出异常的代码
} catch (ExceptionType1 e1) {
    // 处理 ExceptionType1
} catch (ExceptionType2 e2) {
    // 处理 ExceptionType2
} finally {
    // 无论是否发生异常都会执行的代码
}