通过maven添加OSHI依赖:

<dependency>
    <groupId>com.github.dblock</groupId>
    <artifactId>oshi-core</artifactId>
    <version>2.2</version>
</dependency>

获得电池容量剩余百分比:

SystemInfo si = new SystemInfo();
HardwareAbstractionLayer hal = si.getHardware();
for (PowerSource pSource : hal.getPowerSources()) {
    System.out.println(String.format("%n %s @ %.1f%%", pSource.getName(), pSource.getRemainingCapacity() * 100d));
}

java.lang.management包确实比运行时提供了更多的信息——例如，它会将堆内存(ManagementFactory.getMemoryMXBean(). getheapmemoryusage())与非堆内存(ManagementFactory.getMemoryMXBean(). getnonheapmemoryusage())分开。

您还可以获得进程CPU使用情况(无需编写自己的JNI代码)，但是您需要将java.lang.management.OperatingSystemMXBean转换为com.sun.management.OperatingSystemMXBean。这适用于Windows和Linux，我还没有在其他地方测试过。

例如……更频繁地调用get getCpuUsage()方法以获得更准确的读数。

public class PerformanceMonitor { 
    private int  availableProcessors = getOperatingSystemMXBean().getAvailableProcessors();
    private long lastSystemTime      = 0;
    private long lastProcessCpuTime  = 0;

    public synchronized double getCpuUsage()
    {
        if ( lastSystemTime == 0 )
        {
            baselineCounters();
            return;
        }

        long systemTime     = System.nanoTime();
        long processCpuTime = 0;

        if ( getOperatingSystemMXBean() instanceof OperatingSystemMXBean )
        {
            processCpuTime = ( (OperatingSystemMXBean) getOperatingSystemMXBean() ).getProcessCpuTime();
        }

        double cpuUsage = (double) ( processCpuTime - lastProcessCpuTime ) / ( systemTime - lastSystemTime );

        lastSystemTime     = systemTime;
        lastProcessCpuTime = processCpuTime;

        return cpuUsage / availableProcessors;
    }

    private void baselineCounters()
    {
        lastSystemTime = System.nanoTime();

        if ( getOperatingSystemMXBean() instanceof OperatingSystemMXBean )
        {
            lastProcessCpuTime = ( (OperatingSystemMXBean) getOperatingSystemMXBean() ).getProcessCpuTime();
        }
    }
}

我认为最好的方法是通过Hyperic实现SIGAR API。它适用于大多数主要的操作系统(几乎所有现代的操作系统)，并且非常容易使用。开发者在他们的论坛和邮件列表上的反应非常积极。我还喜欢它是GPL2 Apache授权的。他们也提供了大量的Java示例!

SIGAR ==系统信息，收集和报告工具。

为了在java代码中获得1分钟，5分钟和15分钟的系统负载平均值，你可以通过执行cat /proc/loadavg命令来做到这一点，并如下所示:

    Runtime runtime = Runtime.getRuntime();

    BufferedReader br = new BufferedReader(
        new InputStreamReader(runtime.exec("cat /proc/loadavg").getInputStream()));

    String avgLine = br.readLine();
    System.out.println(avgLine);
    List<String> avgLineList = Arrays.asList(avgLine.split("\\s+"));
    System.out.println(avgLineList);
    System.out.println("Average load 1 minute : " + avgLineList.get(0));
    System.out.println("Average load 5 minutes : " + avgLineList.get(1));
    System.out.println("Average load 15 minutes : " + avgLineList.get(2));

通过执行free -m命令获取物理系统内存，然后解释如下:

Runtime runtime = Runtime.getRuntime();

BufferedReader br = new BufferedReader(
    new InputStreamReader(runtime.exec("free -m").getInputStream()));

String line;
String memLine = "";
int index = 0;
while ((line = br.readLine()) != null) {
  if (index == 1) {
    memLine = line;
  }
  index++;
}
//                  total        used        free      shared  buff/cache   available
//    Mem:          15933        3153        9683         310        3097       12148
//    Swap:          3814           0        3814

List<String> memInfoList = Arrays.asList(memLine.split("\\s+"));
int totalSystemMemory = Integer.parseInt(memInfoList.get(1));
int totalSystemUsedMemory = Integer.parseInt(memInfoList.get(2));
int totalSystemFreeMemory = Integer.parseInt(memInfoList.get(3));

System.out.println("Total system memory in mb: " + totalSystemMemory);
System.out.println("Total system used memory in mb: " + totalSystemUsedMemory);
System.out.println("Total system free memory in mb: "   + totalSystemFreeMemory);

至于窗户，我走这边。

    com.sun.management.OperatingSystemMXBean os = (com.sun.management.OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();

    long physicalMemorySize = os.getTotalPhysicalMemorySize();
    long freePhysicalMemory = os.getFreePhysicalMemorySize();
    long freeSwapSize = os.getFreeSwapSpaceSize();
    long commitedVirtualMemorySize = os.getCommittedVirtualMemorySize();

这里有详细的链接。

通常，为了获得较低级别的操作系统信息，您可以通过Runtime.exec()调用特定于操作系统的命令，这些命令会提供您想要的信息，或者读取Linux中的/proc/*等文件。