Tomcat学习--war服务相关状态信息监控

比眉伴天荒 2022-05-26 11:54 235阅读 0赞

#### Tomcat官方管理 ####

tomcat官方提供了自身的管理界面，我们可以根据其实现原理改造和移植其相关功能。主要有以下功能：

（1）每个war服务状态，并提供了启动（start）、停止（stop）、卸载（Undeploy）、重新发布（Reload）以及设置session过期时间等。

![70][]

（2）查看JVM相关内存使用情况

![70 1][]

（3）查看对外服务提供的请求等处理情况等

![70 2][]

（4）每个war服务中相关请求的执行处理情况等。

![70 3][]

#### Tomcat管理改造 ####

首先对于tomcat中war服务，我们可以对实现这些war服务进行启动、停止、卸载、重新加载及获取所有war服务状态的功能。

1、创建MyHostConfig用来继承Tomcat的HostConfig类，主要目的是获取Tomcat的Host对象

public class MyHostConfig extends HostConfig {
    	
    	private static final Log log = LogFactory.getLog(MyHostConfig.class);
    	
    	//获取tomcat的host对象
    	public static Host myHost = null;
    	
    	//重写HostConfig的lifecycleEvent方法
    	@Override
        public void lifecycleEvent(LifecycleEvent event) {
    
            // Identify the host we are associated with
            try {
                host = (Host) event.getLifecycle();
                if (host instanceof StandardHost) {
                    setCopyXML(((StandardHost) host).isCopyXML());
                    setDeployXML(((StandardHost) host).isDeployXML());
                    setUnpackWARs(((StandardHost) host).isUnpackWARs());
                    setContextClass(((StandardHost) host).getContextClass());
    				//获取tomcat的host对象
                    myHost = host;
                }
            } catch (ClassCastException e) {
                log.error(sm.getString("hostConfig.cce", event.getLifecycle()), e);
                return;
            }
    
            // Process the event that has occurred
            if (event.getType().equals(Lifecycle.PERIODIC_EVENT)) {
                check();
            } else if (event.getType().equals(Lifecycle.BEFORE_START_EVENT)) {
                beforeStart();
            } else if (event.getType().equals(Lifecycle.START_EVENT)) {
                start();
            } else if (event.getType().equals(Lifecycle.STOP_EVENT)) {
                stop();
            }
        }
    
    }

将我们自己实现的MyHostConfig对象配置到tomcat的server.xml中，目的是取代其自身实现的HostConfig对象。

然后将MyHostConfig类所在的jar包打包放到tomcat的lib目录下即可，这样我们就可以获取到Host对象，就可以对war包进行启动、停止、重写加载和卸载等操作了。

2、创建一个web服务并在Servlet中获取到myHost对象，代码实现如下：

import java.io.File;
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.util.HashMap;
    import java.util.Map;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.apache.catalina.Container;
    import org.apache.catalina.Context;
    import org.apache.catalina.Host;
    import org.apache.catalina.LifecycleException;
    import org.apache.catalina.Manager;
    import org.apache.catalina.Session;
    import org.apache.catalina.util.ContextName;
    
    import com.alibaba.fastjson.JSON;
    import com.tianjunwei.tomcat.mointor.MyHostConfig;
    
    public class WarMonitorServlet extends HttpServlet{
    	
    	private static final long serialVersionUID = 1L;
    	
    	public void doPost(HttpServletRequest request, HttpServletResponse response)
    				throws ServletException, IOException{
    		 doGet(request, response);
    	}
    
    	public void doGet(HttpServletRequest request, HttpServletResponse response)
    		    throws IOException{
    		
    		Host host = MyHostConfig.myHost;
    		
    		//path名称为war的上下文名称
    		String path = request.getParameter("path");
    		ContextName cn = null;
    	     if (path != null) {
    	         cn = new ContextName(path, request.getParameter("version"));
    	    }
    	    //path路径为start、stop、reload、status和undeploy命令
    	    String command = request.getPathInfo();
    	    
    	    PrintWriter writer = response.getWriter();
    	    if(command == null) {
    	    	writer.write("command is null");
    	    }else if (command.equalsIgnoreCase("/start")) {
    	    	boolean result = start(host, cn);
    	    	writer.write(""+result);
    		}else if (command.equalsIgnoreCase("/stop")) {
    			boolean result = stop(host, cn);
    			writer.write(""+result);
    		}else if (command.equalsIgnoreCase("/reload")) {
    			boolean result = reload(host, cn);
    			writer.write(""+result);
    		}else if (command.equalsIgnoreCase("/undeploy")) {
    			boolean result = undeploy(host, cn);
    			writer.write(""+result);
    		}else if (command.equalsIgnoreCase("/status")) {
    			String status = status(host);
    			writer.write(status);
    		}
    	     writer.flush();
    	}
    	
    	/*
    	 * 获取所有war服务状态
    	 */
    	public static String status(Host host) {
    		Map<String, String> warStatus = new HashMap<String, String>();
    		if(host != null){
    			Container [] containers = host.findChildren();
    			
    			for(int i=0; i< containers.length;i++){
    				String name = containers[i].getName();
    				String status = containers[i].getStateName();
    		    	if(name != null && name.length() > 0){
    		    		warStatus.put(name, status);
    			    	
    		    	}else {
    					warStatus.put("/", status);
    				}
    			}
    		}
    		return JSON.toJSONString(warStatus);
    	}
    	
    	/*
    	 * 启动war服务
    	 */
    	public static boolean start(Host host,ContextName cn) {
    		 Context context = (Context) host.findChild(cn.getName());
             if (context == null) {
               
                 return false;
             }
             try {
    			context.start();
    		} catch (LifecycleException e) {
    			return false;
    		}
    		return true;
    		
    	}
    	
    	/*
    	 * 停止war服务
    	 */
    	public static boolean stop(Host host,ContextName cn) {
    		 Context context = (Context) host.findChild(cn.getName());
             if (context == null) {
                 return false;
             }
            
             try {
    			context.stop();
    		} catch (LifecycleException e) {
    			return false;
    		}
    		return true;
    		
    	}
    
    	/*
    	 * 重新加载war服务
    	 */
    	public static boolean reload(Host host,ContextName cn) {
    		Context context = (Context) host.findChild(cn.getName());
            if (context == null) {
                return false;
            }
            try {
            	 context.reload();
    		} catch (Exception e) {
    			return false;
    		}
            return true;
    	}
    	
    	/*
    	 * 卸载war服务，并删除war文件
    	 */
    	public static boolean undeploy(Host host,ContextName cn) {
    		 String name = cn.getName();
    	     String baseName = cn.getBaseName();
    	     Context context = (Context) host.findChild(name);
    	     try {
    			context.stop();
    		} catch (LifecycleException e) {
    			return false;
    		}
    	     try {
    	    	 File war = new File(host.getAppBaseFile(), baseName + ".war");
                 File dir = new File(host.getAppBaseFile(), baseName);
                 if (war.exists() && !war.delete()) {
                     return false;
                 } else if (dir.exists() && !undeployDir(dir)) {
                     return false;
                 } 
    		} catch (Exception e) {
    			return false;
    		}
    	     return true;
    	     
    	}
    	
    	/*
    	 * 清理超过某个时间的session
    	 */
    	public static boolean expire(Host host,ContextName cn, int idle) {
    		 Context context = (Context) host.findChild(cn.getName());
    		 if(context == null) {
    			 return false;
    		 }
    		 Manager manager = context.getManager() ;
             if(manager == null) {
            	 return false;
             }
             int maxCount = 60;
             int histoInterval = 1;
             int maxInactiveInterval = context.getSessionTimeout();
             if (maxInactiveInterval > 0) {
                 histoInterval = maxInactiveInterval / maxCount;
                 if (histoInterval * maxCount < maxInactiveInterval)
                     histoInterval++;
                 if (0 == histoInterval)
                     histoInterval = 1;
                 maxCount = maxInactiveInterval / histoInterval;
                 if (histoInterval * maxCount < maxInactiveInterval)
                     maxCount++;
             }
             Session [] sessions = manager.findSessions();
             for (int i = 0; i < sessions.length; i++) {
                 int time = (int) (sessions[i].getIdleTimeInternal() / 1000L);
                 if (idle >= 0 && time >= idle*60) {
                     sessions[i].expire();
                 }
             }
             return true;
            
    	}
    	
    	
    	 protected static boolean undeployDir(File dir) {
    
    	        String files[] = dir.list();
    	        if (files == null) {
    	            files = new String[0];
    	        }
    	        for (int i = 0; i < files.length; i++) {
    	            File file = new File(dir, files[i]);
    	            if (file.isDirectory()) {
    	                if (!undeployDir(file)) {
    	                    return false;
    	                }
    	            } else {
    	                if (!file.delete()) {
    	                    return false;
    	                }
    	            }
    	        }
    	        return dir.delete();
    	    }
    	
    }

在web.xml中配置servlet的信息

<servlet>
        <servlet-name>war-monitor</servlet-name>
        <servlet-class>com.tianjunwei.tomcat.servlet.WarMonitorServlet</servlet-class>
      </servlet>
      <servlet-mapping>
        <servlet-name>war-monitor</servlet-name>
        <url-pattern>/war_monitor/*</url-pattern>
      </servlet-mapping>

将war包放到tomcat的webapp目录下启动，接下来通过浏览器可以进行servlet调用进行war服务的状态查看、启动、停止、重新加载和卸载操作（这个权限还是很大的，可以做一些登录限制或者基础SSO或oauth等）。

（1）查看所有war状态：http://localhost:8080/war\_mointor/war\_monitor/status

![70 4][]

war的状态有：NEW，INITIALIZING，INITIALIZED，STARTING\_PREP，STARTING，STARTED，STOPPING\_PREP，STOPPING，STOPPED，DESTROYING，DESTROYED，FAILED

（2）war停止：http://localhost:8080/war\_mointor/war\_monitor/stop?path=/examples

![70 5][]

（3）war启动：http://localhost:8080/war\_mointor/war\_monitor/start?path=/examples

![70 6][]

代码地址[Github][]

[70]: /images/20220526/ef27c961e8fa4931833ddc923b7854b7.png
[70 1]: /images/20220526/77d408a225054f0aa76c69c71e463a2d.png
[70 2]: /images/20220526/7f33087fc12948daa7f72e153c3681df.png
[70 3]: /images/20220526/81d9997f5901403e8b7a2c5bae9f614d.png
[70 4]: /images/20220526/e337edbece7143fdaa6b3ebe45b87edd.png
[70 5]: /images/20220526/ed4c710401754ebf857ff1c4e391345c.png
[70 6]: /images/20220526/4fab889ea506447cad5b32be66e4de23.png
[Github]: https://github.com/IAMTJW/TJW-Tomcat