Java中FilterInputStream和FilterOutputStream的用法详解

package java.io;
public class FilterInputStream extends InputStream {
  protected volatile InputStream in;

  protected FilterInputStream(InputStream in) {
    this.in = in;
  }

  public int read() throws IOException {
    return in.read();
  }

  public int read(byte b[]) throws IOException {
    return read(b, 0, b.length);
  }

  public int read(byte b[], int off, int len) throws IOException {
    return in.read(b, off, len);
  }

  public long skip(long n) throws IOException {
    return in.skip(n);
  }

  public int available() throws IOException {
    return in.available();
  }

  public void close() throws IOException {
    in.close();
  }

  public synchronized void mark(int readlimit) {
    in.mark(readlimit);
  }

  public synchronized void reset() throws IOException {
    in.reset();
  }

  public boolean markSupported() {
    return in.markSupported();
  }
}

package java.io;

public class FilterOutputStream extends OutputStream {
  protected OutputStream out;

  public FilterOutputStream(OutputStream out) {
    this.out = out;
  }

  public void write(int b) throws IOException {
    out.write(b);
  }

  public void write(byte b[]) throws IOException {
    write(b, 0, b.length);
  }

  public void write(byte b[], int off, int len) throws IOException {
    if ((off | len | (b.length - (len + off)) | (off + len)) < 0)
      throw new IndexOutOfBoundsException();

    for (int i = 0 ; i < len ; i++) {
      write(b[off + i]);
    }
  }

  public void flush() throws IOException {
    out.flush();
  }

  public void close() throws IOException {
    try {
     flush();
    } catch (IOException ignored) {
    }
    out.close();
  }
}