Java获取系统信息

java不用jni，也可以获得当前系统性能信息
http://kakaluyi.iteye.com/blog/211492
Java获取系统信息cpu,内存,硬盘,进程等的相关方法
http://www.vvcha.cn/c.aspx?id=170249
以下为转帖
1 获取 CPU使用率,内存,各盘使用情况

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 com.sun.management.OperatingSystemMXBean;

/**
 * 获取windows系统信息（CPU,内存,文件系统）
 */

public class WindowsInfoUtil {
	private static final int CPUTIME = 500;
	private static final int PERCENT = 100;
	private static final int FAULTLENGTH = 10;

	public static void main(String[] args) {
		System.out.println(getCpuRatioForWindows());
		System.out.println(getMemery());
		System.out.println(getDisk());
	}

	// 获取内存使用率
	public static String getMemery() {
		OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory
				.getOperatingSystemMXBean();
		// 总的物理内存+虚拟内存
		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 = "内存已使用:" + 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 "CPU使用率:"
						+ Double.valueOf(
								PERCENT * (busytime) * 1.0
										/ (busytime + idletime)).intValue()
						+ "%";
			} else {
				return "CPU使用率:" + 0 + "%";
			}
		} catch (Exception ex) {
			ex.printStackTrace();
			return "CPU使用率:" + 0 + "%";
		}
	}

	// 读取cpu相关信息
	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 = substring(line, capidx, cmdidx - 1).trim();
				String cmd = substring(line, cmdidx, kmtidx - 1).trim();
				if (cmd.indexOf("wmic.exe") >= 0) {
					continue;
				}
				String s1 = substring(line, kmtidx, rocidx - 1).trim();
				String s2 = 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;
	}

	/**
	 * 由于String.subString对汉字处理存在问题（把一个汉字视为一个字节)，因此在 包含汉字的字符串时存在隐患，现调整如下：
	 * 
	 * @param src
	 *            要截取的字符串
	 * @param start_idx
	 *            开始坐标（包括该坐标)
	 * @param end_idx
	 *            截止坐标（包括该坐标）
	 * @return
	 */
	private 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;
	}
}

2 获取物理占用信息

public class MonitorInfoBean {
	/** 可使用内存. */
	private long totalMemory;

	/** 剩余内存. */
	private long freeMemory;

	/** 最大可使用内存. */
	private long maxMemory;

	/** 操作系统. */
	private String osName;

	/** 总的物理内存. */
	private long totalMemorySize;

	/** 剩余的物理内存. */
	private long freePhysicalMemorySize;

	/** 已使用的物理内存. */
	private long usedMemory;

	/** 线程总数. */
	private int totalThread;

	/** cpu使用率. */
	private double cpuRatio;

	public long getFreeMemory() {
		return freeMemory;
	}

	public void setFreeMemory(long freeMemory) {
		this.freeMemory = freeMemory;
	}

	public long getFreePhysicalMemorySize() {
		return freePhysicalMemorySize;
	}

	public void setFreePhysicalMemorySize(long freePhysicalMemorySize) {
		this.freePhysicalMemorySize = freePhysicalMemorySize;
	}

	public long getMaxMemory() {
		return maxMemory;
	}

	public void setMaxMemory(long maxMemory) {
		this.maxMemory = maxMemory;
	}

	public String getOsName() {
		return osName;
	}

	public void setOsName(String osName) {
		this.osName = osName;
	}

	public long getTotalMemory() {
		return totalMemory;
	}

	public void setTotalMemory(long totalMemory) {
		this.totalMemory = totalMemory;
	}

	public long getTotalMemorySize() {
		return totalMemorySize;
	}

	public void setTotalMemorySize(long totalMemorySize) {
		this.totalMemorySize = totalMemorySize;
	}

	public int getTotalThread() {
		return totalThread;
	}

	public void setTotalThread(int totalThread) {
		this.totalThread = totalThread;
	}

	public long getUsedMemory() {
		return usedMemory;
	}

	public void setUsedMemory(long usedMemory) {
		this.usedMemory = usedMemory;
	}

	public double getCpuRatio() {
		return cpuRatio;
	}

	public void setCpuRatio(double cpuRatio) {
		this.cpuRatio = cpuRatio;
	}
}

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.util.StringTokenizer;

import sun.management.ManagementFactory;

import com.sun.management.OperatingSystemMXBean;

public class cpu {
	private static final int CPUTIME = 30;

	private static final int PERCENT = 100;

	private static final int FAULTLENGTH = 10;

	private static final File versionFile = new File("/proc/version");
	private static String linuxVersion = null;

	public double getCpuRatio() {
		// 操作系统
		String osName = System.getProperty("os.name");
		double cpuRatio = 0;
		if (osName.toLowerCase().startsWith("windows")) {
			return cpuRatio = this.getCpuRatioForWindows();
		} else {
			return cpuRatio = this.getCpuRateForLinux();
		}
	}

	/**
	 * 获得当前的监控对象.
	 * 
	 * @return 返回构造好的监控对象
	 */
	public MonitorInfoBean getMonitorInfoBean() throws Exception {
		int kb = 1024;

		// 可使用内存
		long totalMemory = Runtime.getRuntime().totalMemory() / kb;
		// 剩余内存
		long freeMemory = Runtime.getRuntime().freeMemory() / kb;
		// 最大可使用内存
		long maxMemory = Runtime.getRuntime().maxMemory() / kb;

		OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory
				.getOperatingSystemMXBean();

		// 操作系统
		String osName = System.getProperty("os.name");
		// 总的物理内存
		long totalMemorySize = osmxb.getTotalPhysicalMemorySize() / kb;
		// 剩余的物理内存
		long freePhysicalMemorySize = osmxb.getFreePhysicalMemorySize() / kb;
		// 已使用的物理内存
		long usedMemory = (osmxb.getTotalPhysicalMemorySize() - osmxb
				.getFreePhysicalMemorySize())
				/ kb;

		// 获得线程总数
		ThreadGroup parentThread;
		for (parentThread = Thread.currentThread().getThreadGroup(); parentThread
				.getParent() != null; parentThread = parentThread.getParent())
			;
		int totalThread = parentThread.activeCount();

		double cpuRatio = 0;
		if (osName.toLowerCase().startsWith("windows")) {
			cpuRatio = this.getCpuRatioForWindows();
		} else {
			cpuRatio = this.getCpuRateForLinux();
		}

		// 构造返回对象
		MonitorInfoBean infoBean = new MonitorInfoBean();
		infoBean.setFreeMemory(freeMemory);
		infoBean.setFreePhysicalMemorySize(freePhysicalMemorySize);
		infoBean.setMaxMemory(maxMemory);
		infoBean.setOsName(osName);
		infoBean.setTotalMemory(totalMemory);
		infoBean.setTotalMemorySize(totalMemorySize);
		infoBean.setTotalThread(totalThread);
		infoBean.setUsedMemory(usedMemory);
		infoBean.setCpuRatio(cpuRatio);
		return infoBean;
	}

	private static double getCpuRateForLinux() {
		InputStream is = null;
		InputStreamReader isr = null;
		BufferedReader brStat = null;
		StringTokenizer tokenStat = null;
		try {
			System.out.println("Get usage rate of CUP , linux version: "
					+ linuxVersion);

			Process process = Runtime.getRuntime().exec("top -b -n 1");
			is = process.getInputStream();
			isr = new InputStreamReader(is);
			brStat = new BufferedReader(isr);

			if (linuxVersion.equals("2.4")) {
				brStat.readLine();
				brStat.readLine();
				brStat.readLine();
				brStat.readLine();

				tokenStat = new StringTokenizer(brStat.readLine());
				tokenStat.nextToken();
				tokenStat.nextToken();
				String user = tokenStat.nextToken();
				tokenStat.nextToken();
				String system = tokenStat.nextToken();
				tokenStat.nextToken();
				String nice = tokenStat.nextToken();

				System.out.println(user + " , " + system + " , " + nice);

				user = user.substring(0, user.indexOf("%"));
				system = system.substring(0, system.indexOf("%"));
				nice = nice.substring(0, nice.indexOf("%"));

				float userUsage = new Float(user).floatValue();
				float systemUsage = new Float(system).floatValue();
				float niceUsage = new Float(nice).floatValue();

				return (userUsage + systemUsage + niceUsage) / 100;
			} else {
				brStat.readLine();
				brStat.readLine();

				tokenStat = new StringTokenizer(brStat.readLine());
				tokenStat.nextToken();
				tokenStat.nextToken();
				tokenStat.nextToken();
				tokenStat.nextToken();
				tokenStat.nextToken();
				tokenStat.nextToken();
				tokenStat.nextToken();
				String cpuUsage = tokenStat.nextToken();

				System.out.println("CPU idle : " + cpuUsage);
				Float usage = new Float(cpuUsage.substring(0, cpuUsage
						.indexOf("%")));

				return (1 - usage.floatValue() / 100);
			}

		} catch (IOException ioe) {
			System.out.println(ioe.getMessage());
			freeResource(is, isr, brStat);
			return 1;
		} finally {
			freeResource(is, isr, brStat);
		}

	}

	private static void freeResource(InputStream is, InputStreamReader isr,
			BufferedReader br) {
		try {
			if (is != null)
				is.close();
			if (isr != null)
				isr.close();
			if (br != null)
				br.close();
		} catch (IOException ioe) {
			System.out.println(ioe.getMessage());
		}
	}

	/**
	 * 获得CPU使用率.
	 * 
	 * @return 返回cpu使用率
	 */
	private double 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) / (busytime + idletime))
						.doubleValue();
			} else {
				return 0.0;
			}
		} catch (Exception ex) {
			ex.printStackTrace();
			return 0.0;
		}
	}

	/**
	 * 
	 * 读取CPU信息.
	 * 
	 * @param proc
	 */
	private 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;
				}
				// log.info("line="+line);
				if (caption.equals("System Idle Process")
						|| caption.equals("System")) {
					idletime += Long.valueOf(
							Bytes.substring(line, kmtidx, rocidx - 1).trim())
							.longValue();
					idletime += Long.valueOf(
							Bytes.substring(line, umtidx, wocidx - 1).trim())
							.longValue();
					continue;
				}

				kneltime += Long.valueOf(
						Bytes.substring(line, kmtidx, rocidx - 1).trim())
						.longValue();
				usertime += Long.valueOf(
						Bytes.substring(line, umtidx, wocidx - 1).trim())
						.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;
	}

	/**
	 * 测试方法.
	 * 
	 * @param args
	 * @throws Exception
	 */
	public static void main(String[] args) throws Exception {
		cpu c = new cpu();
		System.out.println("cpu占有率1=" + c.getCpuRatio());
		System.out.println("cpu占有率2=" + c.getCpuRatioForWindows());
		MonitorInfoBean monitorInfo = c.getMonitorInfoBean();
		System.out.println("cpu占有率=" + monitorInfo.getCpuRatio());

		System.out.println("可使用内存=" + monitorInfo.getTotalMemory());
		System.out.println("剩余内存=" + monitorInfo.getFreeMemory());
		System.out.println("最大可使用内存=" + monitorInfo.getMaxMemory());

		System.out.println("操作系统=" + monitorInfo.getOsName());
		System.out.println("总的物理内存=" + monitorInfo.getTotalMemorySize() + "kb");
		System.out.println("剩余的物理内存=" + monitorInfo.getFreeMemory() + "kb");
		System.out.println("已使用的物理内存=" + monitorInfo.getUsedMemory() + "kb");
		System.out.println("线程总数=" + monitorInfo.getTotalThread() + "kb");
	}

}

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;
	}
}