Java 获取JVM内存和物理内存信息

package com.sysinfo;
public class MonitorInfo {
    /** jvm可使用内存. */
    private long totalMemory;
    
    /** jvm剩余内存. */
    private long freeMemory;
    
    /** jvm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 freeMemorySize;
    
    /** 已使用的物理内存. */
    private long usedMemorySize;
    
    /** 核心数. */
    private int processors;

    public long getTotalMemory() {
        return totalMemory;
    }

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

    public long getFreeMemory() {
        return freeMemory;
    }

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

    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 getTotalMemorySize() {
        return totalMemorySize;
    }

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

    public long getFreeMemorySize() {
        return freeMemorySize;
    }

    public void setFreeMemorySize(long freeMemorySize) {
        this.freeMemorySize = freeMemorySize;
    }

    public long getUsedMemorySize() {
        return usedMemorySize;
    }

    public void setUsedMemorySize(long usedMemorySize) {
        this.usedMemorySize = usedMemorySize;
    }

    public int getProcessors() {
        return processors;
    }

    public void setProcessors(int processors) {
        this.processors = processors;
    }
}

package com.sysinfo;

import java.lang.management.ManagementFactory;
import java.math.BigDecimal;

import com.sun.management.OperatingSystemMXBean;

public class MonitorService {
    public MonitorInfo getMonitorInfoBean() throws Exception {
        double mb = 1024 * 1024 * 1.0;
        double gb = 1024 * 1024 * 1024 * 1.0;

        // jvm
        double totalMemory = Runtime.getRuntime().totalMemory() / mb;
        double freeMemory = Runtime.getRuntime().freeMemory() / mb;
        double maxMemory = Runtime.getRuntime().maxMemory() / mb;
        // os
        OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory
                .getOperatingSystemMXBean();
        String osName = System.getProperty("os.name");
        double totalMemorySize = osmxb.getTotalPhysicalMemorySize() / gb;
        double freeMemorySize = osmxb.getFreePhysicalMemorySize() / gb;
        double usedMemorySize = (osmxb.getTotalPhysicalMemorySize() - osmxb
                .getFreePhysicalMemorySize()) / gb;
        // MonitorInfo
        MonitorInfo infoBean = new MonitorInfo();
        infoBean.setTotalMemory(getIntValue(totalMemory));
        infoBean.setFreeMemory(getIntValue(freeMemory));
        infoBean.setMaxMemory(getIntValue(maxMemory));
        infoBean.setOsName(osName);
        infoBean.setTotalMemorySize(getIntValue(totalMemorySize));
        infoBean.setFreeMemorySize(getIntValue(freeMemorySize));
        infoBean.setUsedMemorySize(getIntValue(usedMemorySize));
        infoBean.setProcessors(Runtime.getRuntime().availableProcessors());
        return infoBean;
    }

    /**
     * 四舍五入取整
     * 
     * @param d
     * @return
     */
    private static int getIntValue(double d) {
        return new BigDecimal(d).setScale(0, BigDecimal.ROUND_HALF_UP)
                .intValue();
    }

    public static void main(String[] args) throws Exception {
        MonitorService service = new MonitorService();
        MonitorInfo monitorInfo = service.getMonitorInfoBean();
        // System.out.println("JVM可使用内存=" + monitorInfo.getTotalMemory() +
        // "MB");
        // System.out.println("JVM剩余内存=" + monitorInfo.getFreeMemory() + "MB");
        // System.out.println("JVM最大可使用内存=" + monitorInfo.getMaxMemory() +
        // "MB");

        System.out.println("操作系统=" + monitorInfo.getOsName());
        System.out.println("核心数=" + monitorInfo.getProcessors());
        System.out.println("总的物理内存=" + monitorInfo.getTotalMemorySize() + "GB");
        System.out.println("剩余的物理内存=" + monitorInfo.getFreeMemorySize() + "GB");
        System.out
                .println("已使用的物理内存=" + monitorInfo.getUsedMemorySize() + "GB");
    }
}