Tomcat源码学习--Tomcat模块组成

川长思鸟来 2022-05-29 07:18 241阅读 0赞

1、Server.xml

从tomcat的server.xml中我们可以看到tomcat的相关模块设计，从server.xml文件中解析出来的各个对象都是容器，比如Server、service、Connector和host等，这些容器都有新建、初始化、启动、停止、失败和销毁等状态。

Server.xml示例：

<?xml version="1.0" encoding="UTF-8"?>
    
    
    <Server port="8005" shutdown="SHUTDOWN">
      
      <Service name="Catalina">
    	
        <Connector port="8080" protocol="HTTP/1.1"
                   connectionTimeout="20000"
                   redirectPort="8443" />
    	
        <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
    
    	
        <Engine name="Catalina" defaultHost="localhost">
    
          <Host name="localhost"  appBase="webapps"
                unpackWARs="true" autoDeploy="true">
          </Host>
        </Engine>
      </Service>
    </Server>

2、Tomcat生命周期管理模块的主要类

![Image 1][]

StandardServer、StandardService、Connector、StandardContext这些容器，彼此之间都有父子关系，每个容器都可能包含零个或者多个子容器，这些子容器可能存在不同类型或者相同类型的多个，如下图：

![这里写图片描述][20160417204227221]

3、Tomcat创建web服务编程：

import java.io.File;
    
    import org.apache.catalina.Context;
    import org.apache.catalina.Engine;
    import org.apache.catalina.Host;
    import org.apache.catalina.Lifecycle;
    import org.apache.catalina.LifecycleException;
    import org.apache.catalina.Server;
    import org.apache.catalina.Service;
    import org.apache.catalina.Wrapper;
    import org.apache.catalina.connector.Connector;
    import org.apache.catalina.core.StandardContext;
    import org.apache.catalina.core.StandardEngine;
    import org.apache.catalina.core.StandardHost;
    import org.apache.catalina.core.StandardServer;
    import org.apache.catalina.core.StandardService;
    import org.apache.catalina.startup.Tomcat.FixContextListener;
    
    
    public class Tomcat2 {
    
    	public static void main(String[] args) {
    	    System.setProperty("catalina.base", System.getProperty("user.dir"));
    	    System.err.println("start TestTomcat");
    	    //创建连接器
    	    Connector connector = new Connector("HTTP/1.1");
    	    connector.setPort(8080);
    		
    	    //创建上下文容器
    	    Context context = new StandardContext();
    	    context.setPath("/context");
    
    	    //创建servlet包装类
    	    Wrapper defaultServlet = context.createWrapper();
    	    defaultServlet.setName("test");
                defaultServlet.setServletClass("com.xxxx.servlet.TestServlet");
    	    defaultServlet.setLoadOnStartup(1);
    	    defaultServlet.setOverridable(true);
    		
    	    //上下文容器中添加servlet
    	    context.addChild(defaultServlet);
    	    context.addServletMappingDecoded("/test", "test");
    	    context.addLifecycleListener(new FixContextListener());
    	    
    	    //创建host
    	    Host host = new StandardHost();
    	    host.addChild(context);
    	    host.setName("localhost");
    	    host.setAppBase(System.getProperty("user.dir") + File.separator + ".");
    	    
    	    //创建引擎
    	    Engine engine = new StandardEngine();
    	    engine.setName("Tomcat");
    	    engine.addChild(host);
    	    engine.setDefaultHost("localhost");
    	    engine.getCatalinaBase();
    
    	    //创建一个服务，作为服务器server中的一个服务
    	    Service service = new StandardService();
    	    service.setName("Tomcat");
    	    service.setContainer(engine );
    	    service.addConnector(connector);
    		
    	    //创建服务器
    	    Server server = new StandardServer();
    	    server.setPort(-1);
    	    server.addService(service);
    	    server.setCatalinaBase(new File(System.getProperty("user.dir")));
    	    server.setCatalinaHome(new File(System.getProperty("user.dir")));
    
    	    if (server instanceof Lifecycle) {
    	      try {
    	    	//初始化服务
    	        server.init();
    	        //启动服务
    	        ((Lifecycle) server).start();
    	        //挂起服务
    	        server.await();
    	      }
    	      catch (LifecycleException e) {
    	        e.printStackTrace(System.out);
    	      }
    	    }
    
    	    // Shut down the server
    	    if (server instanceof Lifecycle) {
    	      try {
    	        ((Lifecycle) server).stop();
    	      }
    	      catch (LifecycleException e) {
    	        e.printStackTrace(System.out);
    	      }
    	    }
    	}
    
    }

[Image 1]: 
[20160417204227221]: /images/20220529/386fa26cd9a24d368c91109b2a4da565.png