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用JAVA得到硬盘空间的三种不同方法


  一般来讲,要用java得到硬盘空间,有3种方法:
  
  1. 调用system的command,然后分析得到的结果,这种方法有很强的系统依赖性,linux下和win下要分别写程序
  
  下面是一个win下的例子,编译成功之后,运行java Diskspace yourdir(比如c:\)
  
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  
  /**
  * Determine free disk space for a given directory by
  * parsing the output of the dir command.
  * This class is inspired by the code at
  * Works only under Windows under certain circumstances.
  * Yes, it's that shaky.
  * Requires Java 1.4 or higher.
  * @[EMAIL PROTECTED]
  *Marco Schmidt
  */
  public class Diskspace
  {
  private Diskspace()
  {
  // prevent instantiation of this class
  }
  
  /**
  * Return available free disk space for a directory.
  * @[EMAIL PROTECTED]
  dirName name of the directory
  * @[EMAIL PROTECTED]
  free disk space in bytes or -1 if unknown
  */
  public static long getFreeDiskSpace(String dirName)
  {
  try
  {
  // guess correct 'dir' command by looking at the
  // operating system name
  String os = System.getProperty("os.name");
  String command;
  if (os.equals("Windows NT") ||
  os.equals("Windows 2000"))
  {
  command = "cmd.exe /c dir " + dirName;
  }
  else
  {
  command = "command.com /c dir " + dirName;
  }
  // run the dir command on the argument directory name
  Runtime runtime = Runtime.getRuntime();
  Process process = null;
  process = runtime.exec(command);
  if (process == null)
  {
  return -1;
  }
  // read the output of the dir command
  // only the last line is of interest
  BufferedReader in = new BufferedReader(
  new InputStreamReader(process.getInputStream()));
  String line;
  String freeSpace = null;
  while ((line = in.readLine()) != null)
  {
  freeSpace = line;
  }
  if (freeSpace == null)
  {
  return -1;
  }
  process.destroy();
  // remove dots & commas & leading and trailing whitespace
  freeSpace = freeSpace.trim();
  freeSpace = freeSpace.replaceAll("\\.", "");
  freeSpace = freeSpace.replaceAll(",", "");
  String[] items = freeSpace.split(" ");
  // the first valid numeric value in items after(!) index 0
  // is probably the free disk space
  int index = 1;
  while (index < items.length)
  {
  try
  {
  long bytes = Long.parseLong(items[index++]);
  return bytes;
  }
  catch (NumberFormatException nfe)
  {
  }
  }
  return -1;
  }
  catch (Exception exception)
  {
  return -1;
  }
  }
  
  /**
  * Command line program to print the free diskspace to stdout
  * for all 26 potential root directories A:\ to Z:* (when no parameters are given to this program)
  * or for those directories (drives) specified as parameters.
  * @[EMAIL PROTECTED]
  args program parameters
  */
  public static void main(String[] args)
  {
  if (args.length == 0)
  {
  for (char c = 'A'; c <= 'Z'; c++)
  {
  String dirName = c + ":\\";
  System.out.println(dirName + " " +
  getFreeDiskSpace(dirName));
  }
  }
  else
  {
  for (int i = 0; i < args.length; i++)
  {
  System.out.println(args[i] + " " +
  getFreeDiskSpace(args[i]));
  }
  }
  }
  }
  
  方法二:使用Jconfig,可以跨平台
  
  从http://www.tolstoy.com/samizdat/jconfig.html上下载jconfig.
  
  下载的包的sample里有很简单的例子,如果是要得到磁盘空间的话:
  
  用FileRegistry.getVolumes()得到DiskVolume
  
  然后call getFreeSpace()和getMaxCapacity()
  
  就是这么简单..:)
  
  方法三:jni
  
  这个是解决所有和OS相关操作的万能利器了.
  
  例子我也懒得写了.
  
  写一个dll然后call之即可.
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