java不用jni，也可以获得当前系统性能信息

2019-11-17 04:10:40

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最近做个项目，就是要取得cpu占有率等等的系统信息，一开始以为要用动态链接库了，但后来发现可以像下面这样做，不去调用jni，这样省去了很多看新技术的时间o(∩_∩)o...

在java中，可以获得总的物理内存、剩余的物理内存、已使用的物理内存等信息，下面例子可以取得这些信息，并且获得在Windows下的内存使用率。
首先编写一个MonitorInfoBean类，用来装载监控的一些信息，包括物理内存、剩余的物理内存、已使用的物理内存、内存使用率等字段，该类的代码如下：

Java代码
package com.amgkaka.performance;

/** */ /**
* 监视信息的JavaBean类.
* @author amg
* @version 1.0
* Creation date: 2008-4-25 - 上午10:37:00
*/
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;
    }
}
package com.amgkaka.performance;

/** *//**
* 监视信息的JavaBean类.
* @author amg
* @version 1.0
* Creation date: 2008-4-25 - 上午10:37:00
*/
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;
    }
}
接着编写一个获得当前的监控信息的接口，该类的代码如下所示：

Java代码
package com.amgkaka.performance;

/** */ /**
* 获取系统信息的业务逻辑类接口.
* @author amg * @version 1.0
* Creation date: 2008-3-11 - 上午10:06:06
*/
public   interface IMonitorService {
    /** */ /**
     * 获得当前的监控对象.
     * @return 返回构造好的监控对象
     * @throws Exception
     * @author amgkaka
     * Creation date: 2008-4-25 - 上午10:45:08
     */
    public MonitorInfoBean getMonitorInfoBean() throws Exception;

}
package com.amgkaka.performance;

/** *//**
* 获取系统信息的业务逻辑类接口.
* @author amg * @version 1.0
* Creation date: 2008-3-11 - 上午10:06:06
*/
public interface IMonitorService {
    /** *//**
     * 获得当前的监控对象.
     * @return 返回构造好的监控对象
     * @throws Exception
     * @author amgkaka
     * Creation date: 2008-4-25 - 上午10:45:08
     */
    public MonitorInfoBean getMonitorInfoBean() throws Exception;

} 该类的实现类MonitorServiceImpl如下所示：

Java代码
package com.amgkaka.performance;

import java.io.InputStreamReader;
import java.io.LineNumberReader;

import sun.management.ManagementFactory;

import com.sun.management.OperatingSystemMXBean;

/** */ /**
* 获取系统信息的业务逻辑实现类.
* @author amg * @version 1.0 Creation date: 2008-3-11 - 上午10:06:06
*/
public   class MonitorServiceImpl implements IMonitorService {
    //可以设置长些，防止读到运行此次系统检查时的cpu占用率，就不准了
    private   static   final   int CPUTIME = 5000 ;

    private   static   final   int PERCENT = 100 ;

    private   static   final   int FAULTLENGTH = 10 ;

    /** */ /**
     * 获得当前的监控对象.
     * @return 返回构造好的监控对象
     * @throws Exception
     * @author amg     * Creation date: 2008-4-25 - 上午10:45:08
     */
    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();
        }

        // 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;
    }

    /** */ /**
     * 获得CPU使用率.
     * @return 返回cpu使用率
     * @author amg     * Creation date: 2008-4-25 - 下午06:05:11
     */
    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
     * @return
     * @author amg     * Creation date: 2008-4-25 - 下午06:10:14
     */
    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
     * @author amg     * Creation date: 2008-4-30 - 下午04:47:29
     */
    public   static   void main(String[] args) throws Exception {
        IMonitorService service = new MonitorServiceImpl();
        MonitorInfoBean monitorInfo = service.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" );
    }
}
package com.amgkaka.performance;

import java.io.InputStreamReader;
import java.io.LineNumberReader;

import sun.management.ManagementFactory;

import com.sun.management.OperatingSystemMXBean;

/** *//**
* 获取系统信息的业务逻辑实现类.
* @author amg * @version 1.0 Creation date: 2008-3-11 - 上午10:06:06
*/
public class MonitorServiceImpl implements IMonitorService {
//可以设置长些，防止读到运行此次系统检查时的cpu占用率，就不准了
private static final int CPUTIME = 5000;

private static final int PERCENT = 100;

private static final int FAULTLENGTH = 10;

    /** *//**
     * 获得当前的监控对象.
     * @return 返回构造好的监控对象
     * @throws Exception
     * @author amg     * Creation date: 2008-4-25 - 上午10:45:08
     */
    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();
        }

        // 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;
    }

    /** *//**
     * 获得CPU使用率.
     * @return 返回cpu使用率
     * @author amg     * Creation date: 2008-4-25 - 下午06:05:11
     */
    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
     * @return
     * @author amg     * Creation date: 2008-4-25 - 下午06:10:14
     */
    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
     * @author amg     * Creation date: 2008-4-30 - 下午04:47:29
     */
    public static void main(String[] args) throws Exception {
        IMonitorService service = new MonitorServiceImpl();
        MonitorInfoBean monitorInfo = service.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");
    }
}
该实现类中需要用到一个自己编写byte的工具类，该类的代码如下所示：

Java代码
package com.amgkaka.performance;

/** */ /**
* byte操作类.
* @author amg * @version 1.0
* Creation date: 2008-4-30 - 下午04:57:23
*/
public   class Bytes {
    /** */ /**
     * 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
     */
    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;
    }
}
package com.amgkaka.performance;

/** *//**
* byte操作类.
* @author amg * @version 1.0
* Creation date: 2008-4-30 - 下午04:57:23
*/
public class Bytes {
    /** *//**
     * 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
     */
    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;
    }
}
运行下MonitorBeanImpl类，读者将会看到当前的内存、cpu利用率等信息。