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前言：本文是从“ ”一文剥离出来的，专门探讨如何使用JMX监控Tomcat，本系列文章详见本人专栏： 。
一、激活Tomcat的JMX远程配置
要通过JMX远程监控Tomcat，首先需要激活Tomcat的JMX远程配置。
① 先修改Tomcat的启动脚本，windows下为bin/catalina.bat（linux下为catalina.sh），添加以下内容，8999是jmxremote使用的端口号，第二个false表示不需要鉴权：
set JMX_REMOTE_CONFIG=-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=falseset CATALINA_OPTS=%CATALINA_OPTS% %JMX_REMOTE_CONFIG%
要注意以上语句的位置不能太后面，可以加在【if "%OS%" == "Windows_NT" setlocal】一句后的大段的注释后面。
参考官方说明：
② 上面的配置是不需要鉴权的，如果需要鉴权则添加的内容为：
set JMX_REMOTE_CONFIG=-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=true -Dcom.sun.management.jmxremote.password.file=../conf/jmxremote.password -Dcom.sun.management.jmxremote.access.file=../conf/jmxremote.accessset CATALINA_OPTS=%CATALINA_OPTS% %JMX_REMOTE_CONFIG%
③ 然后复制并修改授权文件 $JAVA_HOME/jre/lib/management下有jmxremote.access和jmxremote.password的模板文件，将两个文件复制到$CATALINA_BASE/conf目录下
◆ 修改$CATALINA_BASE/conf/jmxremote.access 添加内容： monitorRole readonly controlRole readwrite ◆ 修改$CATALINA_BASE/conf/jmxremote.password 添加内容： monitorRole chenfeng controlRole chenfeng
注意： 如果进行了以上步骤导致Tomcat启动不了，那么很可能是密码文件的权限问题 需要修改jmxremote.password文件的访问权限，只有运行Tomcat的用户才能拥有访问权限 ： Windows的NTFS文件系统下，选中文件，点右键 -->“属性”-->“安全”--> 点“高级”--> 点“更改权限”--> 去掉“从父项继承....”--> 弹出窗口中选“删除”，这样就删除了所有访问权限。再选“添加”--> “高级”--> “立即查找”，选中你的用户（或用户组，如果选用户不行那就选用户组），例administrator，点“确定"，“确定"。来到权限项目窗口，勾选“完全控制”，点“确定”，OK了。 官方的提示： The password file should be read-only and only accessible by the operating system user Tomcat is running as.
④ 重新启动Tomcat，在Windows命令行输入“netstat -a”查看配置的端口号是否已打开，如果打开，说明上面的配置成功了。
⑤ 使用jconsole测试JMX。
运行$JAVA_HOME/bin目录下的jconsole.exe，打开J2SE监视和管理控制台，然后建立连接，如果是本地的Tomcat则直接选择然后点击连接，如果是远程的，则进入远程选项卡，填写地址、端口号、用户名、口令即可连接。。Mbean属性页中给出了相应的数据，Catalina中是tomcat的，java.lang是jvm的。对于加粗的黑体属性值，需双击一下才可看内容。
二、使用JMX监控Tomcat示例代码
String jmxURL = "service:jmx:rmi:///jndi/rmi://192.168.10.93:8999/jmxrmi";JMXServiceURL serviceURL = new JMXServiceURL(jmxURL);Map map = new HashMap();// 用户名密码，在jmxremote.password文件中查看String[] credentials = new String[] { "monitorRole", "tomcat" };map.put("jmx.remote.credentials", credentials);JMXConnector connector = JMXConnectorFactory.connect(serviceURL, map);MBeanServerConnection mbsc = connector.getMBeanServerConnection();// 端口最好是动态取得ObjectName threadObjName = new ObjectName("Catalina:type=ThreadPool,name=http-8080");MBeanInfo mbInfo = mbsc.getMBeanInfo(threadObjName);// tomcat的线程数对应的属性值String attrName = "currentThreadCount";MBeanAttributeInfo[] mbAttributes = mbInfo.getAttributes();System.out.println("currentThreadCount:" + mbsc.getAttribute(threadObjName, attrName));
三、完整的示例代码文件
import java.lang.management.MemoryUsage;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Formatter;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;import javax.management.MBeanAttributeInfo;import javax.management.MBeanInfo;import javax.management.MBeanServerConnection;import javax.management.ObjectInstance;import javax.management.ObjectName;import javax.management.openmbean.CompositeDataSupport;import javax.management.remote.JMXConnector;import javax.management.remote.JMXConnectorFactory;import javax.management.remote.JMXServiceURL;public class JMXTest { /** * @param args */ public static void main(String[] args) { try { String jmxURL = "service:jmx:rmi:///jndi/rmi://127.0.0.1:8999/jmxrmi"; JMXServiceURL serviceURL = new JMXServiceURL(jmxURL); Map map = new HashMap(); String[] credentials = new String[] { "monitorRole", "tomcat" }; map.put("jmx.remote.credentials", credentials); JMXConnector connector = JMXConnectorFactory.connect(serviceURL, map); MBeanServerConnection mbsc = connector.getMBeanServerConnection(); // 端口最好是动态取得 ObjectName threadObjName = new ObjectName( "Catalina:type=ThreadPool,name=http-8080"); MBeanInfo mbInfo = mbsc.getMBeanInfo(threadObjName); String attrName = "currentThreadCount";// tomcat的线程数对应的属性值 MBeanAttributeInfo[] mbAttributes = mbInfo.getAttributes(); System.out.println("currentThreadCount:" + mbsc.getAttribute(threadObjName, attrName)); // heap for (int j = 0; j < mbsc.getDomains().length; j++) { System.out.println("###########" + mbsc.getDomains()[j]); } Set MBeanset = mbsc.queryMBeans(null, null); System.out.println("MBeanset.size() : " + MBeanset.size()); Iterator MBeansetIterator = MBeanset.iterator(); while (MBeansetIterator.hasNext()) { ObjectInstance objectInstance = (ObjectInstance) MBeansetIterator .next(); ObjectName objectName = objectInstance.getObjectName(); String canonicalName = objectName.getCanonicalName(); System.out.println("canonicalName : " + canonicalName); if (canonicalName .equals("Catalina:host=localhost,type=Cluster")) { // Get details of cluster MBeans System.out.println("Cluster MBeans Details:"); System.out .println("========================================="); // getMBeansDetails(canonicalName); String canonicalKeyPropList = objectName .getCanonicalKeyPropertyListString(); } } // ------------------------- system ---------------------- ObjectName runtimeObjName = new ObjectName("java.lang:type=Runtime"); System.out.println("厂商:" + (String) mbsc.getAttribute(runtimeObjName, "VmVendor")); System.out.println("程序:" + (String) mbsc.getAttribute(runtimeObjName, "VmName")); System.out.println("版本:" + (String) mbsc.getAttribute(runtimeObjName, "VmVersion")); Date starttime = new Date((Long) mbsc.getAttribute(runtimeObjName, "StartTime")); SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); System.out.println("启动时间:" + df.format(starttime)); Long timespan = (Long) mbsc.getAttribute(runtimeObjName, "Uptime"); System.out.println("连续工作时间:" + JMXTest.formatTimeSpan(timespan)); // ------------------------ JVM ------------------------- // 堆使用率 ObjectName heapObjName = new ObjectName("java.lang:type=Memory"); MemoryUsage heapMemoryUsage = MemoryUsage .from((CompositeDataSupport) mbsc.getAttribute(heapObjName, "HeapMemoryUsage")); long maxMemory = heapMemoryUsage.getMax();// 堆最大 long commitMemory = heapMemoryUsage.getCommitted();// 堆当前分配 long usedMemory = heapMemoryUsage.getUsed(); System.out.println("heap:" + (double) usedMemory * 100 / commitMemory + "%");// 堆使用率 MemoryUsage nonheapMemoryUsage = MemoryUsage .from((CompositeDataSupport) mbsc.getAttribute(heapObjName, "NonHeapMemoryUsage")); long noncommitMemory = nonheapMemoryUsage.getCommitted(); long nonusedMemory = heapMemoryUsage.getUsed(); System.out.println("nonheap:" + (double) nonusedMemory * 100 / noncommitMemory + "%"); ObjectName permObjName = new ObjectName( "java.lang:type=MemoryPool,name=Perm Gen"); MemoryUsage permGenUsage = MemoryUsage .from((CompositeDataSupport) mbsc.getAttribute(permObjName, "Usage")); long committed = permGenUsage.getCommitted();// 持久堆大小 long used = heapMemoryUsage.getUsed();// System.out.println("perm gen:" + (double) used * 100 / committed + "%");// 持久堆使用率 // -------------------- Session --------------- ObjectName managerObjName = new ObjectName( "Catalina:type=Manager,*"); Set s = mbsc.queryNames(managerObjName, null); for (ObjectName obj : s) { System.out.println("应用名:" + obj.getKeyProperty("path")); ObjectName objname = new ObjectName(obj.getCanonicalName()); System.out.println("最大会话数:" + mbsc.getAttribute(objname, "maxActiveSessions")); System.out.println("会话数:" + mbsc.getAttribute(objname, "activeSessions")); System.out.println("活动会话数:" + mbsc.getAttribute(objname, "sessionCounter")); } // ----------------- Thread Pool ---------------- ObjectName threadpoolObjName = new ObjectName( "Catalina:type=ThreadPool,*"); Set s2 = mbsc.queryNames(threadpoolObjName, null); for (ObjectName obj : s2) { System.out.println("端口名:" + obj.getKeyProperty("name")); ObjectName objname = new ObjectName(obj.getCanonicalName()); System.out.println("最大线程数:" + mbsc.getAttribute(objname, "maxThreads")); System.out.println("当前线程数:" + mbsc.getAttribute(objname, "currentThreadCount")); System.out.println("繁忙线程数:" + mbsc.getAttribute(objname, "currentThreadsBusy")); } } catch (Exception e) { e.printStackTrace(); } } public static String formatTimeSpan(long span) { long minseconds = span % 1000; span = span / 1000; long seconds = span % 60; span = span / 60; long mins = span % 60; span = span / 60; long hours = span % 24; span = span / 24; long days = span; return (new Formatter()).format("%1$d天 %2$02d:%3$02d:%4$02d.%5$03d", days, hours, mins, seconds, minseconds).toString(); }}
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