1、过程
（1）既可以充当一个输入流, 也可以冲淡一个输出流
（2）支持从文件的开头读取、写入
（3）支持从任意位置的读取、写入(插入)
（4）RandomAccessFile类需要指定的访问模式:
2、实例
public void RandomAccessFile(String src, String srcMode, String dest, String destMode) {
RandomAccessFile accessFile = null;
RandomAccessFile accessFile1 = null;
try {
accessFile = new RandomAccessFile(new File(src), srcMode);
accessFile = new RandomAccessFile(new File(dest), destMode);
byte[] bytes = new byte[1024];
int length;
while ((length = accessFile.read(bytes)) != -1) {
accessFile1.write(bytes, 0, length);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (accessFile != null)
try {
accessFile.close();
} catch (IOException e) {
e.printStackTrace();
}
if (accessFile1 != null) {
try {
accessFile1.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
} 
