如何利用Java获取系统的信息（CPU、内存、各盘符使用情况）_java 获取系统盘信息

/***********************************************************************
 * Project: gpsAdapter
 * Note: Console Application
 **********************************************************************/
 
/** 
 *
 * @author HuangHaifeng 1.0
 * @date   2016-1-12
 * @copyright CCompass
 *     增加用于监控系统cpu,memory的工具类
 */
package com.hhf.test;
 
import java.io.File;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.lang.management.ManagementFactory;
import java.util.ArrayList;
import java.util.List;
 
import javax.management.MBeanServerConnection;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;
 
import com.sun.management.OperatingSystemMXBean;
 
public class WindowsInfoUtil {
 
	private static final int CPUTIME = 500;
	private static final int PERCENT = 100;
	private static final int FAULTLENGTH = 10;
 
	// 获取内存使用率
	public static String getMemery() {
 
		OperatingSystemMXBean osmxb = ManagementFactory.getPlatformMXBean(OperatingSystemMXBean.class);
		long totalvirtualMemory = osmxb.getTotalSwapSpaceSize(); // 剩余的物理内存
		long freePhysicalMemorySize = osmxb.getFreePhysicalMemorySize();
		Double compare = (Double) (1 - freePhysicalMemorySize * 1.0 / totalvirtualMemory) * 100;
 
		String str = compare.intValue() + "%";
		return str;
 
	}
 
	// 获取文件系统使用率
	public static List<String> getDisk() {
 
		// 操作系统
		List<String> list = new ArrayList<String>();
 
		for (char c = 'A'; c <= 'Z'; c++) {
			String dirName = c + ":/";
			File win = new File(dirName);
			if (win.exists()) {
				long total = (long) win.getTotalSpace();
				long free = (long) win.getFreeSpace();
				Double compare = (Double) (1 - free * 1.0 / total) * 100;
				String str = c + ":盘已使用" + compare.intValue() + "%";
				list.add(str);
			}
		}
		return list;
 
	}
 
	// 获得cpu使用率
	public static String getCpuRatioForWindows() {
 
		try {
			String procCmd = System.getenv("windir")
					+ "\\system32\\wbem\\wmic.exe process get Caption,CommandLine,KernelModeTime,ReadOperationCount,ThreadCount,UserModeTime,WriteOperationCount";
			// 取进程信息
			long[] c0 = readCpu(Runtime.getRuntime().exec(procCmd));
			Thread.sleep(CPUTIME);
			long[] c1 = readCpu(Runtime.getRuntime().exec(procCmd));
 
			if (c0 != null && c1 != null) {
				long idletime = c1[0] - c0[0];
				long busytime = c1[1] - c0[1];
				return   Double.valueOf(PERCENT * (busytime) * 1.0 / (busytime + idletime)).intValue() + "%";
			} else {
				return   0 + "%";
			}
 
		} catch (Exception ex) {
			ex.printStackTrace();
			return  0 + "%";
		}
	}
 
	private static long[] readCpu(final Process proc) {
		long[] retn = new long[2];
		try {
			proc.getOutputStream().close();
			InputStreamReader ir = new InputStreamReader(proc.getInputStream());
			LineNumberReader input = new LineNumberReader(ir);
			String line = input.readLine();
			if (line == null || line.length() < FAULTLENGTH) {
				return null;
 
			}
 
			int capidx = line.indexOf("Caption");
			int cmdidx = line.indexOf("CommandLine");
			int rocidx = line.indexOf("ReadOperationCount");
			int umtidx = line.indexOf("UserModeTime");
			int kmtidx = line.indexOf("KernelModeTime");
			int wocidx = line.indexOf("WriteOperationCount");
			long idletime = 0;
			long kneltime = 0;
			long usertime = 0;
			while ((line = input.readLine()) != null) {
				if (line.length() < wocidx) {
 
					continue;
 
				}
               // 字段出现顺序：Caption,CommandLine,KernelModeTime,ReadOperationCount,
				          //ThreadCount,UserModeTime,WriteOperation
				String caption = Bytes.substring(line, capidx, cmdidx - 1).trim();
				String cmd = Bytes.substring(line, cmdidx, kmtidx - 1).trim();
				if (cmd.indexOf("wmic.exe") >= 0) {
					continue;
				}
				String s1 = Bytes.substring(line, kmtidx, rocidx - 1).trim();
				String s2 = Bytes.substring(line, umtidx, wocidx - 1).trim();
				if (caption.equals("System Idle Process") || caption.equals("System")) {
 
					if (s1.length() > 0)
 
						idletime += Long.valueOf(s1).longValue();
					if (s2.length() > 0)
						idletime += Long.valueOf(s2).longValue();
					continue;
				}
				if (s1.length() > 0)
 
					kneltime += Long.valueOf(s1).longValue();
				if (s2.length() > 0)
					usertime += Long.valueOf(s2).longValue();
			}
			retn[0] = idletime;
			retn[1] = kneltime + usertime;
			return retn;
		} catch (Exception ex) {
			ex.printStackTrace();
		} finally {
			try {
				proc.getInputStream().close();
 
			} catch (Exception e) {
				e.printStackTrace();
			}
 
		}
		return null;
 
	}
	static class Bytes {
		public static String substring(String src, int start_idx, int end_idx) {
			byte[] b = src.getBytes();
			String tgt = "";
			for (int i = start_idx; i <= end_idx; i++) {
				tgt += (char) b[i];
			}
 
			return tgt;
		}
	}
	public static void main(String[] args) throws Exception {
 
		System.out.println("cpu占有率=" + WindowsInfoUtil.getCpuRatioForWindows());
		System.out.println("可使用内存=" + WindowsInfoUtil.getMemery());
		System.out.println("各盘占用情况：" + WindowsInfoUtil.getDisk());
		
	}
}

这时就会出现com.sun.management.OperatingSystemMXBean这个类找不到！

        这里的工程需要用到rt.jar，当我们额外下载导入rt.jar就可以解决这个问题，但是对于jdk来说本身是具有jar包的，原因是eclipse将这些访问受限制的API设置成了错误，导致不能import。