サーブレット,Filter,Listener呼び出し順序,ライフサイクルの実験解析

11261 ワード
listener
サーブレット、Filter、Listenerの呼び出し順序、ライフサイクルを実験で検証します.
1、サンプル項目
ディレクトリ構造:
web.xml 
<?xml version="1.0" encoding="UTF-8"?>
<!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>
    <listener>
        <listener-class>edu.shao.webapp.sample.listener.MyServletRequestListener</listener-class>
    </listener>
    <listener>
        <listener-class>edu.shao.webapp.sample.listener.MyServletContextListener</listener-class>
    </listener>
    
    <filter>
        <filter-name>ResponseFilter</filter-name>
        <filter-class>edu.shao.webapp.sample.filter.ResponseFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>ResponseFilter</filter-name>
        <servlet-name>hello_world</servlet-name>
    </filter-mapping>
    
    <filter>
        <filter-name>LogFilter</filter-name>
        <filter-class>edu.shao.webapp.sample.filter.LogFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>LogFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    
    <servlet>
        <servlet-name>hello_world</servlet-name>
        <servlet-class>edu.shao.webapp.sample.HelloServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>hello_world</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
    
    <servlet>
        <servlet-name>early_servlet</servlet-name>
        <servlet-class>edu.shao.webapp.sample.EarlyServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>early_servlet</servlet-name>
        <url-pattern>/early</url-pattern>
    </servlet-mapping>
</web-app>

MyServiceletContextListenerクラス:
public class MyServletContextListener implements ServletContextListener {
    public static Logger logger=LogManager.getLogger(MyServletContextListener.class);

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        logger.info("Servlet context initialized.");
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        logger.info("Servlet context destroyed.");
    }
}

MyServiceletRequestListenerクラス:
public class MyServletRequestListener implements ServletRequestListener {
    public static Logger logger=LogManager.getLogger(MyServletRequestListener.class);

    @Override
    public void requestDestroyed(ServletRequestEvent sre) {
        logger.info("Servlet request destroyed.");
    }

    @Override
    public void requestInitialized(ServletRequestEvent sre) {
        logger.info("Servlet request initialized.");
    }
}

ResponseFilterクラス:
public class ResponseFilter implements Filter {
    public static Logger logger=LogManager.getLogger(ResponseFilter.class);
    
    @Override
    public void init(FilterConfig arg0) throws ServletException {
        logger.info("Response Filter initialized.");
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res,
            FilterChain chain) throws IOException, ServletException {
        chain.doFilter(req, res);
        res.getWriter().write("--@2013 Mr.Shao");
    }

    @Override
    public void destroy() {
        logger.info("Response Filter destroyed.");
    }
}

LogFilterクラス:
public class LogFilter implements Filter {
    public static Logger logger=LogManager.getLogger(LogFilter.class);
    
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        logger.info("Log Filter initialized.");
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httpServletRequest = (HttpServletRequest)request;
        logger.info("Intercept Url="+httpServletRequest.getRequestURI());
        
        long start=System.currentTimeMillis();
        chain.doFilter(request, response);
        long end=System.currentTimeMillis();
        logger.info(request.getRemoteAddr()+": time used :"+(end-start));
    }

    @Override
    public void destroy() {
        logger.info("Log Filter destroyed.");
    }
}

HelloServiceクラス:
public class HelloServlet extends HttpServlet {
    public static Logger logger=LogManager.getLogger(HelloServlet.class);

    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        logger.debug("Do Get Method.");
        resp.getWriter().print("Hello World");
    }
    
    public void init() throws ServletException {
        logger.debug("Hello Servlet initialized.");
    }
    
    public void destroy() {
        logger.debug("Hello Servlet destroyed.");
    }
}

EarlyServiceletクラス:
public class EarlyServlet extends HttpServlet {
    public static Logger logger=LogManager.getLogger(EarlyServlet.class);

    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        logger.debug("Do Get Method.");
        resp.getWriter().print("This message is created in EarlyServlet");
    }
    
    public void init() throws ServletException {
        logger.debug("Early Servlet initialized.");
    }
    
    public void destroy() {
        logger.debug("Early Servlet destroyed.");
    }
}

2、テスト操作
1、tomcatサービスを起動する
2、アクセスhttp://10.130.29.198:8080/test/(index.htmlへのアクセス)
3、アクセスhttp://10.130.29.198:8080/test/hello
4、アクセスhttp://10.130.29.198:8080/test/early
5、tomcatサービスを停止する
3、ログ出力
(出力時間によって、人為的にログを分割し、観察しやすい)
1、tomcatサービスを起動する
2013-03-28 18:14:08,954 INFO  - [MyServletContextListener - contextInitialized] Servlet context initialized.
2013-03-28 18:14:08,983 INFO  - [LogFilter - init] Log Filter initialized.
2013-03-28 18:14:08,984 INFO  - [ResponseFilter - init] Response Filter initialized.
2013-03-28 18:14:08,991 DEBUG - [EarlyServlet - init] Early Servlet initialized.
2、アクセスhttp://10.130.29.198:8080/test/(index.htmlへのアクセス)
2013-03-28 18:14:18,946 INFO  - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:18,957 INFO  - [LogFilter - doFilter] Intercept Url=/test/
2013-03-28 18:14:18,962 INFO  - [LogFilter - doFilter] 10.130.29.198: time used :4
2013-03-28 18:14:18,963 INFO  - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
3、アクセスhttp://10.130.29.198:8080/test/hello
2013-03-28 18:14:34,713 INFO  - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:34,714 DEBUG - [HelloServlet - init] Hello Servlet initialized.
2013-03-28 18:14:34,716 INFO  - [LogFilter - doFilter] Intercept Url=/test/hello
2013-03-28 18:14:34,717 DEBUG - [HelloServlet - doGet] Do Get Method.
2013-03-28 18:14:34,720 INFO  - [LogFilter - doFilter] 10.130.29.198: time used :3
2013-03-28 18:14:34,721 INFO  - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
4、アクセスhttp://10.130.29.198:8080/test/early
2013-03-28 18:14:42,124 INFO  - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:42,127 INFO  - [LogFilter - doFilter] Intercept Url=/test/early
2013-03-28 18:14:42,128 DEBUG - [EarlyServlet - doGet] Do Get Method.
2013-03-28 18:14:42,129 INFO  - [LogFilter - doFilter] 10.130.29.198: time used :1
2013-03-28 18:14:42,130 INFO  - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
5、tomcatサービスを停止する
2013-03-28 18:14:49,723 DEBUG - [EarlyServlet - destroy] Early Servlet destroyed.
2013-03-28 18:14:49,724 DEBUG - [HelloServlet - destroy] Hello Servlet destroyed.
2013-03-28 18:14:49,724 INFO  - [LogFilter - destroy] Log Filter destroyed.
2013-03-28 18:14:49,726 INFO  - [ResponseFilter - destroy] Response Filter destroyed.
2013-03-28 18:14:49,727 INFO  - [MyServletContextListener - contextDestroyed] Servlet context destroyed.
4、分析
1.Tomcat(サーブレットコンテナ)起動時にListenerとサーブレットContextが最初に初期化される.最初に出力されるログは次のとおりです.
　　2013-03-28 18:14:08,954 INFO - [MyServletContextListener - contextInitialized] Servlet context initialized.
2、FilterはTomcat(サーブレットコンテナ)起動時に初期化する.
　　2013-03-28 18:14:08,983 INFO - [LogFilter - init] Log Filter initialized.
　　2013-03-28 18:14:08,984 INFO - [ResponseFilter - init] Response Filter initialized.
3.サーブレットが1を構成している場合、このサーブレットもTomcat(サーブレットコンテナ)の起動時に初期化されます.例えばEarlyServicelet:
　　2013-03-28 18:14:08,991 DEBUG - [EarlyServlet - init] Early Servlet initialized.
4、リクエストごとにRequestが初期化され、リクエストに応答すると、リクエストが破棄されます.
　　2013-03-28 18:14:18,946 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
　　......
　　2013-03-28 18:14:18,963 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
5、Filterは要求の実行前後に、いくつかの処理を行うことができる.
(1)要求実行前:2013-03-28 18:14:34716 INFO-[LogFilter-doFilter]Intercept Url=/test/hello
(2)実行要求:2013-03-28 18 18:14:34717 DEBUG-[HelloService-doGet]Do Get Method.
(3)要求実行後:2013-03-28 18:14:34720 INFO-[LogFilter-doFilter]10.130.29.198:time used:3
6、サーブレットが1を構成していない場合、このサーブレットはTomcat起動時に初期化されるのではなく、要求到来時に初期化される.例えばHelloService:
　　2013-03-28 18:14:34,714 DEBUG - [HelloServlet - init] Hello Servlet initialized.
7、サーブレット初期化後、要求の終了に伴ってログアウトされません.HelloServiceletは初期化され、要求が終了するとHelloServiceletのdestroy()は呼び出されません.
8、Tomcatを閉じると、サーブレット、Filter、Listenerが順次ログアウトされる.
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