Java中的IO基本用法

先贴一下我在作业中用到的三种文件输入辅助类、三种文件输出辅助类

public class BuffIn implements InHelp{
  private BufferedReader bufferedReader;

  public BuffIn(String path) {
    try {
      bufferedReader = new BufferedReader(
              new InputStreamReader(new FileInputStream(path), "UTF-8"));
    }catch (IOException e){
      System.err.println("请提供正确路径");
      PathException e2 = new PathException(path,"路径地址错误");
      Logs.logger.error(e2.getMessage());
    }
  }

  @Override
  public String read() throws IOException {
    TimeCounter.start();
    String s = bufferedReader.readLine();
    TimeCounter.pause();
    return s;
  }

  @Override
  public void shut() throws IOException {
    bufferedReader.close();
  }
}

public class BuffreaderIn implements InHelp{
  private BufferedReader bufferedReader;
  public BuffreaderIn(String path) {
    try {
      bufferedReader = new BufferedReader(new FileReader(path));
    }catch (IOException e){
      System.err.println("请提供正确路径");
      PathException e2 = new PathException(path,"路径地址错误");
      Logs.logger.error(e2.getMessage());
    }
  }

  @Override
  public String read() throws IOException {
    TimeCounter.start();
    String s = bufferedReader.readLine();
    TimeCounter.pause();
    return s;
  }

  @Override
  public void shut() throws IOException {
    bufferedReader.close();
  }
}

public class ScannerIn implements InHelp{
  private Scanner scanner;
  private java.io.File file;
  public ScannerIn(String path) {
    try {
      file = new java.io.File(path);
      scanner = new Scanner(file);
    }catch (IOException e){
      System.err.println("请提供正确路径");
      exception.PathException e2 = new exception.PathException(path,"路径地址错误");
      logs.Logs.logger.error(e2.getMessage());
    }
  }

  @Override
  public String read() throws IOException {
    TimeCounter.start();
    if(!scanner.hasNextLine()) return null;
    String s = scanner.nextLine();
    TimeCounter.pause();
    return s;
  }

  @Override
  public void shut() throws IOException {
    scanner.close();
  }
}

public class BuffOut implements OutHelp{
  private BufferedWriter bufferedWriter;
  private FileOutputStream fileOutputStream;
  public BuffOut(String path) {
    try {
      fileOutputStream = new FileOutputStream(path);
      bufferedWriter = new BufferedWriter(
              new OutputStreamWriter(fileOutputStream, "UTF-8"));
    }catch (IOException e){
      System.err.println("请提供正确路径");
      PathException e2 = new PathException(path,"路径地址错误");
      Logs.logger.error(e2.getMessage());
    }
  }

  @Override
  public void write(String s) throws IOException {
    TimeCounter.start();
    bufferedWriter.write(s);
    TimeCounter.pause();
  }

  @Override
  public void shut() throws IOException {
    bufferedWriter.close();
    fileOutputStream.close();
  }
}

public class StreamOut implements OutHelp{
  private OutputStreamWriter outputStreamWriter;
  private FileOutputStream fileOutputStream;

  public StreamOut(String path) {
    try {
      fileOutputStream = new FileOutputStream(path);
      outputStreamWriter = new OutputStreamWriter(fileOutputStream, "UTF-8");
    }catch (IOException e){
      System.err.println("请提供正确路径");
      PathException e2 = new PathException(path,"路径地址错误");
      Logs.logger.error(e2.getMessage());
    }
  }

  @Override
  public void write(String s) throws IOException {
    TimeCounter.start();
    outputStreamWriter.write(s);
    TimeCounter.pause();
  }

  @Override
  public void shut() throws IOException {
    outputStreamWriter.close();
    fileOutputStream.close();
  }
}

public class WriterOut implements OutHelp {
  private FileWriter fileWriter;

  public WriterOut(String path) {
    try {
      fileWriter = new FileWriter(path);
    }catch (IOException e){
      System.err.println("请提供正确路径");
      PathException e2 = new PathException(path,"路径地址错误");
      Logs.logger.error(e2.getMessage());
    }
  }

  @Override
  public void write(String s) throws IOException {
    TimeCounter.start();
    fileWriter.write(s);
    TimeCounter.pause();
  }

  @Override
  public void shut() throws IOException {
    fileWriter.close();
  }
}

主要的类如下：

1. File（文件特征与管理）：用于文件或者目录的描述信息，例如生成新目录，修改文件名，删除文件，判断文件所在路径等。

2. InputStream（二进制格式操作）：抽象类，基于字节的输入操作，是所有输入流的父类。定义了所有输入流都具有的共同特征。

3. OutputStream（二进制格式操作）：抽象类。基于字节的输出操作。是所有输出流的父类。定义了所有输出流都具有的共同特征。

4.Reader（文件格式操作）：抽象类，基于字符的输入操作。

5. Writer（文件格式操作）：抽象类，基于字符的输出操作。

6. RandomAccessFile（随机文件操作）：一个独立的类，直接继承至Object.它的功能丰富，可以从文件的任意位置进行存取（输入输出）操作。

针对一些频繁的设备交互，Java语言系统预定了3个可以直接使用的流对象，分别是：

·        System.in（标准输入），通常代表键盘输入。

·        System.out（标准输出）：通常写往显示器。

·        System.err（标准错误输出）：通常写往显示器。

IOException异常类的子类
　   1.public class  EOFException ：   非正常到达文件尾或输入流尾时，抛出这种类型的异常。

2.public class FileNotFoundException：   当文件找不到时，抛出的异常。

3.public class InterruptedIOException： 当I/O操作被中断时，抛出这种类型的异常。