深入刨析tomcat 之---第15篇 对应20章, myAdmin案例代码

writedby 张艳涛

有没有和我一样做到第20章的?今天基本结束了本书的阅读.最后一个案例没有demo,那我写了一回,如果有需要的可以在本地试试

路径 D:wksp_studydesignbookserverwebappsmyadminWEB-INFclassesMyAdminServlet.class

D:wksp_studydesignbookserverwebappsmyadminWEB-INFweb.xml

以上是俩个文件,第三个文件D:wksp_studydesignbookwebappsmyadmin.xml

第一文件内容

//MyAdminServlet.java

import com.zyt.tomcat.ex02.Response;
import org.apache.commons.modeler.ManagedBean;
import org.apache.commons.modeler.Registry;
import org.apache.naming.ResourceRef;

import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectInstance;
import javax.management.ObjectName;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.Set;

public class MyAdminServlet extends HttpServlet {
    private Registry registry;
    private MBeanServer mBeanServer;
    @Override
    public void init() throws ServletException {
        registry = (Registry) getServletContext().getAttribute("org.apache.catalina.Registry");
        if (registry == null) {
            System.out.println("Register not available");
            return;
        }
        mBeanServer = ((MBeanServer) getServletContext().getAttribute("org.apache.catalina.MBeanServer"));
        if (mBeanServer == null) {
            System.out.println("MBeanServer not avaiale");
            return;
        }
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html");
        PrintWriter out = resp.getWriter();
        if (registry == null || mBeanServer==null) {
            out.println("registry or MbeanServer not found");
            return;
        }
        out.println("<html><head></head><body>");
        String action = req.getParameter("action");
        if ("listBeans".equals(action)) {
            listAllManagedBeans(out);
        }else  if("listContexts".equals(action)){
            listAllContexts(out);
        }else if("removeContext".equals("contextObjectName")){
            String contextObjectName = req.getParameter("contextObjectName");
            removeContext(contextObjectName, out);
        }else {
            out.println("Invalid command");
        }
        out.println("</body></html>");
    }
    private void listAllManagedBeans(PrintWriter out){
        String[] managedBeans = registry.findManagedBeans();
        for (int i = 0; i < managedBeans.length; i++) {
            out.println(managedBeans[i]+"<br/>");
        }

    }
    private void listAllContexts(PrintWriter out){
        try {
            ObjectName objectName = new ObjectName("Catalina:type=Context,*");
            Set<ObjectName> set = mBeanServer.queryNames(objectName, null);
            Iterator<ObjectName> iterator = set.iterator();
            while (iterator.hasNext()) {
                ObjectName obj = (ObjectName) iterator.next();
                out.println(obj+"<br/>");

            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    private  void removeContext(String contextObjectName,PrintWriter out){
        try {
            ObjectName mBeanFactoryObjectName = new ObjectName("Catalina:type=MBeanFactory");
            if (mBeanFactoryObjectName != null) {
                String operation = "removeContext";
                String[] params = new String[1];
                params[0] =contextObjectName;
                String signature[] = {"java.lang.String"};
                mBeanServer.invoke(mBeanFactoryObjectName, operation, params, signature);
                out.println("context removed");

            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

第二个文件

<?xml version="1.0" encoding="ISO-8859-1"?>

<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
  <servlet>
    <servlet-name>myAdmin</servlet-name>
    <servlet-class>MyAdminServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>myAdmin</servlet-name>
    <url-pattern>/myAdmin</url-pattern>
  </servlet-mapping>
</web-app>

第三个文件

<Context path="/myadmin" docBase="../server/webapps/myadmin" debug="8" privileged="true" reloadable="true">
</Context>

访问第一个api

http://localhost:8080/myadmin/myAdmin?action=listBeans

http://localhost:8080/myadmin/myAdmin?action=listContexts

随书代码下载地址:https://www.cnblogs.com/caophoenix/p/11295681.html

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原文地址：https://www.cnblogs.com/zytcomeon/p/15021273.html