获取当前jvm数据

获取当前jvm数据

import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.lang.management.ManagementFactory;

import org.apache.log4j.Logger;

import com.sun.management.OperatingSystemMXBean;

public class MonitorUtil {
    private static final Logger logger = Logger.getLogger(MonitorUtil.class);
    //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. 
     */  
    public static String 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 = getCpuRatioForWindows();  
        }  
          
        StringBuffer sb = new StringBuffer();
        double total = (Runtime.getRuntime().totalMemory()) / (1024.0 * 1024);
        double max = (Runtime.getRuntime().maxMemory()) / (1024.0 * 1024);
        double free = (Runtime.getRuntime().freeMemory()) / (1024.0 * 1024);
        logger.info("Java 虚拟机试图使用的最大内存量(当前JVM的最大可用内存) maxMemory(): " + max + "MB<br/>");
        logger.info("Java 虚拟机中的内存总量(当前JVM占用的内存总数) totalMemory(): " + total + "MB<br/>");
        logger.info("Java 虚拟机中的空闲内存量(当前JVM空闲内存) freeMemory(): " + free + "MB<br/>");
        logger.info("因为JVM只有在需要内存时才占用物理内存使用，所以freeMemory()的值一般情况下都很小，<br/>" +
        "而JVM实际可用内存并不等于freeMemory()，而应该等于 maxMemory() - totalMemory() + freeMemory()。<br/>");
        logger.info("JVM实际可用内存: " + (max - total + free) + "MB<br/>");
        logger.info("cpu占有率=" + cpuRatio+"/n");
        logger.info("可使用内存=" + totalMemory+"/n");  
        logger.info("剩余内存=" + freeMemory+"/n");  
        logger.info("最大可使用内存=" + maxMemory+"/n");  
          
        logger.info("操作系统=" + osName+"/n");  
        logger.info("总的物理内存=" + totalMemorySize + "kb/n");  
        logger.info("剩余的物理内存=" + freeMemory + "kb/n");  
        logger.info("已使用的物理内存=" + usedMemory + "kb/n");  
        logger.info("线程总数=" + totalThread+ "/n");  
        return sb.toString();  
    }  
  
    /** *//** 
     * 获得CPU使用率. 
     */  
    private static 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. 
   */  
    private static 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 = substring(line, capidx, cmdidx - 1)  
                        .trim();  
                String cmd = 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(  
                            substring(line, kmtidx, rocidx - 1).trim())  
                            .longValue();  
                    idletime += Long.valueOf(  
                            substring(line, umtidx, wocidx - 1).trim())  
                            .longValue();  
                    continue;  
                }  
  
                kneltime += Long.valueOf(  
                        substring(line, kmtidx, rocidx - 1).trim())  
                        .longValue();  
                usertime += Long.valueOf(  
                        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;  
    }  
        /** *//** 
         * 由于String.subString对汉字处理存在问题： 
         * @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;  
        }  
   }