JSP获取CPU使用率、系统内存、虚拟机内存等情况(不用JNI)

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：
package performance;

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：
package performance;

/**
* 获取系统信息的业务逻辑类接口.
*/
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
     */
    public MonitorInfoBean getMonitorInfoBean() throws Exception;
}
该类的实现类MonitorServiceImpl如下所示：
package performance;

import java.io.BufferedReader;
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;

/**
*
* 获取系统信息的业务逻辑实现类.
*
* @author GuoHuang
*/
public class MonitorServiceImpl implements IMonitorService {
    private static final int CPUTIME = 30;
    private static final int PERCENT = 100;
    private static final int FAULTLENGTH = 10;
    private static String linuxVersion = null;

    /**
     * 获得当前的监控对象.
     *
     * @return 返回构造好的监控对象
     * @throws Exception
     * @author GuoHuang
     */
    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;

补充：Web开发 , Jsp ,