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");
     }
 }