使用apache commons io包中的FileSystemUtils和FileUtils类获得磁盘剩余空间：

import org.apache.commons.io.FileSystemUtils;
import org.apache.commons.io.FileUtils;

import java.io.IOException;

public class GetFreeDiskSpace {

    public static void main(String[] args) {

        try {

            // Set a string with the path
            String path = "C:";

            // Get free space in KB
            long freeSpaceInKB = FileSystemUtils.freeSpaceKb(path);

            // Calculate free space in GB
            long freeSpaceInGB = freeSpaceInKB / FileUtils.ONE_MB;

            // Print the result
            System.out.println("Free space of " + path + " drive = " + freeSpaceInGB + " GB");

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}