深入解析FileInputStream和FileOutputStream

本文主要是介绍深入解析FileInputStream和FileOutputStream，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

FileInputStream和FileOutputStream类属于字节类，可以操作任意类型的文件。在数据流的处理过程中，有两种情况。
（1）以单个字节的形式读写文件
（2）以数据块的形式读写文件
从JDK的源码中，我们可以看出来：

FileInputStream的读：

public native int read() throws IOException;
private native int readBytes(byte b[], int off, int len) throws IOException;

FileOutputStream的写：

public native void write(int b) throws IOException;
private native void writeBytes(byte b[], int off, int len) throws IOException;

FileInputStream和FileOutputStream最常用的地方也就是文件的复制过程。下面通过两个例子来说明一下：
例子一：单个字节的读写

public class Test
{public static void main(String[] args){File src = new File("d:\\src.txt");File dst = new File("d:\\dst.txt");doSaveFile(src, dst);}public static void doSaveFile(File src, File dst){InputStream in = null;OutputStream out = null;try{in = new FileInputStream(src);out = new FileOutputStream(dst);int len = 0;while ((len = in.read()) > 0){//len表示读取的字节out.write(len);}}catch (Exception e){}finally{if (null != in){try{in.close();}catch (IOException e){}}if (null != out){try{out.close();}catch (IOException e){}}}}
}

例子二：数据块的读写

public class Test
{private final static int BUFFER_SIZE = 16 * 1024;public static void main(String[] args){File src = new File("d:\\src.txt");File dst = new File("d:\\dst.txt");doSaveFile(src, dst);}public static void doSaveFile(File src, File dst){InputStream in = null;OutputStream out = null;try{in = new FileInputStream(src);out = new FileOutputStream(dst);byte[] buffer = new byte[BUFFER_SIZE];int len = 0;while ((len = in.read(buffer)) > 0){//len表示读取的字节数out.write(buffer, 0, len);}}catch (Exception e){}finally{if (null != in){try{in.close();}catch (IOException e){}}if (null != out){try{out.close();}catch (IOException e){}}}}
}