How Can I get free memory ?

[sathish_2111]

Hi

I have two question...

How can I get the free memory space of every hard drives in the machine?

How can I get the amount memory used by a particular process?

[JavaBean]

I don't think there are is feasible ways of doing it with pure Java. I think you will need to write them using JNI.

[mir2ming]

i give a demo to you:

Code:

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] 
*/
public class Diskspace
{
private Diskspace()
{
// prevent instantiation of this class
}

/**
* Return available free disk space for a directory. 字串8 
* @[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 字串1 
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; 字串3 
}
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 " " 
getFreeDiskSpace(args));
}
}
}
}