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Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

程序员文章站 2024-02-29 14:51:16
 standardengine[tomcat].standardhost[localhost]的启动与standardengine不在同一个线程中,它的start:&nbs...

 standardengine[tomcat].standardhost[localhost]的启动与standardengine不在同一个线程中,它的start:   

// start our child containers, if any
  container children[] = findchildren();
  list<future<void>> results = new arraylist<>();
  for (int i = 0; i < children.length; i++) {
   results.add(startstopexecutor.submit(new startchild(children[i])));
  }
  boolean fail = false;
  for (future<void> result : results) {
   try {
    result.get();
   } catch (exception e) {
    log.error(sm.getstring("containerbase.threadedstartfailed"), e);
    fail = true;
   }
  }
  if (fail) {
   throw new lifecycleexception(
     sm.getstring("containerbase.threadedstartfailed"));
  }
 private static class startchild implements callable<void> {
  private container child;
  public startchild(container child) {
   this.child = child;
  }
  @override
  public void call() throws lifecycleexception {
   child.start();
   return null;
  }
 }

  这个start流程中,initinternal方法是containerbase的代码,还是那个初始化startstopexecutor的,线程名例如thread[localhost-startstop-1,5,main],这次是用来初始化host的子容器的,然后是standardhost中的startinternal方法,主要是注册了一个errorvalue,如果现有的pipeline中没有errorvalue,则反射创建org.apache.catalina.valves.errorreportvalve实例,并加入pipeline中,容器pipeline加入value时会发布一个container.add_valve_event事件,与engine一样,之后进入containerbase的startinternal,但是这次realm是null不需要启动,然后findchildren出standardengine[tomcat]. standardhost [localhost].standardcontext[],然后同样新开个线程new startchild,start同样是上面的代码,需要特别说明的是,这次before_init的事件有监听的了,fixcontextlistener,disablepersistsessionlistener,memoryleaktrackinglistener;fixcontextlistener监听的处理,会加入一个用于不做用户身份认证的安全检查的value:               

context context = (context) event.getlifecycle();
    if (event.gettype().equals(lifecycle.configure_start_event)) {
     context.setconfigured(true);
    }
    // loginconfig is required to process @servletsecurity
    // annotations
    if (context.getloginconfig() == null) {
     context.setloginconfig(
       new loginconfig("none", null, null, null));
     context.getpipeline().addvalve(new nonloginauthenticator());
    }

   disablepersistsessionlistener监听只处理start事件,所以这里只判断了一下发现不是就出去了,其实这里可以思考下,有没有更好的办法,让监听不只是广播方式,能不能用订阅方式,先不细想了,接着看代码,memoryleaktrackinglistener只监听了after_start事件,这步同样什么都没做。

  于是来到了standardcontext的initinternal,它的super.initinternal又是一个startstopexecutor,containerbase的super.initinternal就不再说了,发送j2ee.object.created消息:         

notification notification = new notification("j2ee.object.created",
     this.getobjectname(), sequencenumber.getandincrement());
   broadcaster.sendnotification(notification);

   notification是eventobject的子类,代表由mbean发出的通知,mbean server发出的通知会包含发出的mbean的引用,如果mbean注册了监听,可以通过object name或引用获取消息发出者,官方建议使用object name;sendnotification方法:

 /**
  * sends a notification.
  *
  * if an {@code executor} was specified in the constructor, it will be given one
  * task per selected listener to deliver the notification to that listener.
  *
  * @param notification the notification to send.
  */
 public void sendnotification(notification notification) {
  if (notification == null) {
   return;
  }
  boolean enabled;
  for (listenerinfo li : listenerlist) {
   try {
    enabled = li.filter == null ||
     li.filter.isnotificationenabled(notification);
   } catch (exception e) {
    if (logger.debugon()) {
     logger.debug("sendnotification", e);
    }
    continue;
   }
   if (enabled) {
    executor.execute(new sendnotifjob(notification, li));
   }
  }
 }

  发完消息就转变状态为初始化完成,因为监听器是注册在context容器上的,于是after_init事件又触发了那三个监听器,这一阶段监听器什么都没处理走了下过场而已;before_start同走过场;然后standardcontext的startinternal方法,发布了个j2ee.state.starting消息object name为tomcat:j2eetype=webmodule,name=//localhost/,j2eeapplication=none, j2eeserver=none;setconfigured(false)还没有正确的配置;设置webresourceroot,webresourceroot提供整个应用资源处理类的各种方法,内嵌用的实现类是standardroot,set的过程中加了写锁:        

try {
    setresources(new standardroot(this));
   } catch (illegalargumentexception e) {
    log.error(sm.getstring("standardcontext.resourcesinit"), e);
    ok = false;
   }

   standardroot的属性allresources:

private final list<list<webresourceset>> allresources =
   new arraylist<>();
 {
  allresources.add(preresources);
  allresources.add(mainresources);
  allresources.add(classresources);
  allresources.add(jarresources);
  allresources.add(postresources);
 }

  http://tomcat.apache.org/tomcat-8.0-doc/api/org/apache/catalina/webresourceroot.html有相关说明,我就不翻译了。

  set之后就是启动resourcesstart,initinternal执行的是standardroot的initinternal方法,super.initinternal中依然是那两行代码,register(cache, getobjectnamekeyproperties() + ",name=cache")会发送mbeanservernotification. registration_notification通知,生成objectname这里cachejmxname是tomcat:type=webresourceroot,host=localhost,context=/,name=cache;registerurlstreamhandlerfactory里面的代码是tomcaturlstreamhandlerfactory.register()这行代码的注释说这是为了支持war包内的jar资源的。之后是循环上面的allresources,init里面加入的webresourceset,但是由于全都是空的,所以等于没执行,就不说了,回头再仔细看看什么情况下回不为空,还是内嵌的就是空的。createmainresourceset主要是设置个主目录,例如/tmp/tomcat-docbase.3031819619941848514.80,然后是各种资源该放在哪个子目录的一些设置代码;这次资源有一个了,所以可以有一个start了,dirresourceset的;super.initinternal()的super是abstractfileresourceset:

 //-------------------------------------------------------- lifecycle methods
 @override
 protected void initinternal() throws lifecycleexception {
  super.initinternal();
  // is this an exploded web application?
  if (getwebappmount().equals("")) {
   // look for a manifest
   file mf = file("meta-inf/manifest.mf", true);
   if (mf != null && mf.isfile()) {
    try (fileinputstream fis = new fileinputstream(mf)) {
     setmanifest(new manifest(fis));
    } catch (ioexception e) {
     log.warn(sm.getstring("dirresourceset.manifestfail", mf.getabsolutepath()), e);
    }
   }
  }
 }

  super.initinternal主要是对base目录进行了一些规范化处理,规范的方法主要是unixfilesystem中的canonicalize其中还使用expiringcache对路径做了缓存,另外还有在normalize方法中对路径中类似"\.."的部分做了处理。webappmount是web应用发布资源的位置,必须以‘/'开头,这里应该是通过它来判断不是war包部署的模式,然后由于manifest没找到,所以方法返回初始化完成,这个资源一路状态变化就启动完了。

  回到standardroot,接下来是processwebinflib方法,代码很直观,不解释了:

private void processwebinflib() {
  webresource[] possiblejars = listresources("/web-inf/lib", false);
  for (webresource possiblejar : possiblejars) {
   if (possiblejar.isfile() && possiblejar.getname().endswith(".jar")) {
    createwebresourceset(resourcesettype.classes_jar,
      "/web-inf/classes", possiblejar.geturl(), "/");
   }
  }
 }

  接下来也不解释:

 // need to start the newly found resources
  for (webresourceset classresource : classresources) {
   classresource.start();
  }

  cache.enforceobjectmaxsizelimit是计算缓存限制的,详细的可以参考,至此standardroot的启动完成就只剩下改状态了。

  回到standardcontext,因为classloader已经有了不需要new了;接着创建rfc6265cookieprocessor类型的cookieprocessor实例,关于rfc6265标准参考;character set mapper因为已经初始化好了只判断了下;工作目录处理,先根据host和engine名生成路径如:work/tomcat/localhost/root,结合前面的base创建目录例如/tmp/tomcat.3726907762383543267.80/work/tomcat/localhost/root,然后初始化standardcontext中的applicationcontext类型可继承的全局变量context构造用参数是this(context = new applicationcontext(this)),返回new applicationcontextfacade(this);将上面的全路径设置给servletcontext.tempdir属性,并将这个属性设置为只读:

 /**
  * set an attribute as read only.
  */
 void setattributereadonly(string name) {
  if (attributes.containskey(name))
   readonlyattributes.put(name, name);
 }

  之后是对扩展进行验证,这里说一下,standardcontext中不管是这里的获取资源还是之后的读取classloader都是加了读锁的:

 // validate required extensions
  boolean dependencycheck = true;
  try {
   dependencycheck = extensionvalidator.validateapplication
    (getresources(), this);
  } catch (ioexception ioe) {
   log.error(sm.getstring("standardcontext.extensionvalidationerror"), ioe);
   dependencycheck = false;
  }

  catalina.usenaming用于是否开启命名服务支持,开启了就会注册namingcontextlistener监听器:

if (!dependencycheck) {
   // do not make application available if depency check fails
   ok = false;
  }
  // reading the "catalina.usenaming" environment variable
  string usenamingproperty = system.getproperty("catalina.usenaming");
  if ((usenamingproperty != null)
   && (usenamingproperty.equals("false"))) {
   usenaming = false;
  }
  if (ok && isusenaming()) {
   if (getnamingcontextlistener() == null) {
    namingcontextlistener ncl = new namingcontextlistener();
    ncl.setname(getnamingcontextname());
    ncl.setexceptiononfailedwrite(getjndiexceptiononfailedwrite());
    addlifecyclelistener(ncl);
    setnamingcontextlistener(ncl);
   }
  }

  classloader oldccl = bindthread()里有个threadbindinglistener,不过因为webapplicationclassloader是null,所以等于没执行,返回的是null,里面的逻辑还不少,命名服务也没开contextbindings.bindthread于是也没执行。

  old的没有,但是loader还是有的,到了loader的start了,主要要说的是webapploader的startinternal方法,classloader创建:       

 classloader = createclassloader();
   classloader.setresources(context.getresources());
   classloader.setdelegate(this.delegate);

  buildclasspath的主要功能是遍历各个层次的classloader并将其中classpath的jar拼成一个字符串,例如
:/usr/lib/jvm/java-8-oracle/jre/lib/charsets.jar:/usr/lib/jvm/java-8-oracle/jre/lib/deploy.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/cldrdata.jar...,是以':'作为分隔是因为我的开发环境是linux,在windows中应该是';':

 while (loader != null) {
   if (!buildclasspath(classpath, loader)) {
    break;
   }
   loader = loader.getparent();
  }
  if (delegate) {
   // delegation was enabled, go back and add the webapp paths
   loader = getclassloader();
   if (loader != null) {
    buildclasspath(classpath, loader);
   }
  }

         delegate之前提过了,是会向基loader类委托的;setclasspath的最后一句:servletcontext.setattribute(globals.class_path_attr, this.classpath)。

  setpermissions方法,由于我这第一个判断就返回了,而且看上去代码也很直观,我就不说了:

private void setpermissions() {
  if (!globals.is_security_enabled)
   return;
  if (context == null)
   return;
  // tell the class loader the root of the context
  servletcontext servletcontext = context.getservletcontext();
  // assigning permissions for the work directory
  file workdir =
   (file) servletcontext.getattribute(servletcontext.tempdir);
  if (workdir != null) {
   try {
    string workdirpath = workdir.getcanonicalpath();
    classloader.addpermission
     (new filepermission(workdirpath, "read,write"));
    classloader.addpermission
     (new filepermission(workdirpath + file.separator + "-",
          "read,write,delete"));
   } catch (ioexception e) {
    // ignore
   }
  }
  for (url url : context.getresources().getbaseurls()) {
   classloader.addpermission(url);
  }
 }

      ((lifecycle) classloader).start(),这个classloader是tomcatembeddedwebappclassloader走的是webappclassloaderbase中的start方法,这里因为是内嵌的版本(我没确认,猜测)所以也并没有加载到东西,所以也不细说了:

 public void start() throws lifecycleexception {
  state = lifecyclestate.starting_prep;
  webresource classes = resources.getresource("/web-inf/classes");
  if (classes.isdirectory() && classes.canread()) {
   localrepositories.add(classes.geturl());
  }
  webresource[] jars = resources.listresources("/web-inf/lib");
  for (webresource jar : jars) {
   if (jar.getname().endswith(".jar") && jar.isfile() && jar.canread()) {
    localrepositories.add(jar.geturl());
    jarmodificationtimes.put(
      jar.getname(), long.valueof(jar.getlastmodified()));
   }
  }
  state = lifecyclestate.started;
 }

  然后生成objectname例如:tomcat:context=/,host=localhost,type=tomcatembeddedwebappclassloader,然后注册mbean:getmbeanserver().registermbean( mbean, oname);webapploader的start就没什么了,started之后就是设置了几个属性:

 // since the loader just started, the webapp classloader is now
    // created.
    setclassloaderproperty("clearreferencesrmitargets",
      getclearreferencesrmitargets());
    setclassloaderproperty("clearreferencesstopthreads",
      getclearreferencesstopthreads());
    setclassloaderproperty("clearreferencesstoptimerthreads",
      getclearreferencesstoptimerthreads());
    setclassloaderproperty("clearreferenceshttpclientkeepalivethread",
      getclearreferenceshttpclientkeepalivethread());

  这里的unbindthread因为前面的bind几乎没做什么,所以什么也没做;接着的bindthread主要讲线程与classloader做了绑定: thread.currentthread().setcontextclassloader (webapplicationclassloader),至于threadbindinglistener.bind()由于threadbindinglistener用了个空实现,所以这里什么也没做。

  接下来用读锁取到realm并start它;接下来发布configure_start事件,fixcontextlistener中执行了context.setconfigured(true)。

  终于到了standardwrapper(standardengine[tomcat].standardhost[localhost].standardcontext[].standardwrapper[default])的start了,initinternal直接就是containerbase的初始化startstopexecutor,startinternal方法是发了个j2ee.state.starting的消息,objectname是tomcat:j2eetype=servlet, webmodule=//localhost/, name=default, j2eeapplication=none, j2eeserver=none,然后又到containerbase的startinternal,然而由于它没有子容器了,所以这里并没有startchild的任务产生;于是开始执行它的value,先start它的pipeline,startinternal方法依然是standardpipeline的,按顺序start,由于到这的时候一个都没有,所以执行的是basic的,standardwrappervalve的initinternal中只有一句注释:don't register this valve in jmx;startinternal的最后是threadstart,但由于backgroundprocessordelay是-1所以并没有启动背景线程;setavailable(0l)设置可用,它的说明 the date and time at which this servlet will become available (in milliseconds since the epoch), or zero if the servlet is available;然后发送一个消息j2ee.state.running,objectname是tomcat:j2eetype=servlet,webmodule=//localhost/,name=default,j2eeapplication=none,j2eeserver=none;

  standardwrapper就启动完了,回到standardcontext,start它的pipeline;与standardwrapper的pipeline不同,它之前被注册过nonloginauthenticator,它的startinternal方法定义在authenticatorbase,方法中设置了jaspicappcontextid(例如:tomcat/localhost ),然后获取上级容器也就是host的pipeline中的所有value,并找到其中singlesignon类型的value,明显是用于单点登录的,我这里没有,于是又去找了上一级容器engine当然还是没有,于是就往下走了;实例化了一个standardsessionidgenerator,设置安全随机数生成算法我这里是sha1prng,生成器类名为null,生成器provider也是null,然后就是下一个value对象standardcontextvalve的start,只不过它的start是标准的什么额外事都没干,于是回到了standardcontext中。下面一段主要是执行了tomcatembeddedcontext中的setmanager方法:

@override
 public void setmanager(manager manager) {
  if (manager instanceof managerbase) {
   ((managerbase) manager).setsessionidgenerator(new lazysessionidgenerator());
  }
  super.setmanager(manager);
 }

  这里判断是true,lazysessionidgenerator整个的代码:

class lazysessionidgenerator extends standardsessionidgenerator {

@override
 protected void startinternal() throws lifecycleexception {
  setstate(lifecyclestate.starting);
 }
}

  tomcatembeddedcontext的super.setmanager(manager)的super是standardcontext,在写锁中执行的,spring中多数的set都是交换的方式,先set个old保存下来,然后判断新值和old是否相同,不相同用新的并将新值绑定容器,相同直接返回;getservletcontext().setattribute(globals.resources_attr, getresources())没什么好解释的;setnamingresources(new namingresourcesimpl());然后init这个namingresources,namingresourcesimpl的initinternal,在设置当前已知命名资源前设置resourcerequireexplicitregistration用于避免时序问题,重复注册是正常的,后面一段我不想解释:

 for (contextresource cr : resources.values()) {
   try {
    mbeanutils.creatembean(cr);
   } catch (exception e) {
    log.warn(sm.getstring(
      "namingresources.mbeancreatefail", cr.getname()), e);
   }
  }
  for (contextenvironment ce : envs.values()) {
   try {
    mbeanutils.creatembean(ce);
   } catch (exception e) {
    log.warn(sm.getstring(
      "namingresources.mbeancreatefail", ce.getname()), e);
   }
  }
  for (contextresourcelink crl : resourcelinks.values()) {
   try {
    mbeanutils.creatembean(crl);
   } catch (exception e) {
    log.warn(sm.getstring(
      "namingresources.mbeancreatefail", crl.getname()), e);
   }
  }

        init之后是start,start中只发布了个configure_start事件。

  setinstancemanager(new defaultinstancemanager(context, injectionmap, this, this.getclass().getclassloader())),instancemanager主要是用于创建和回收实例,然后绑定:         

 getservletcontext().setattribute(
      instancemanager.class.getname(), getinstancemanager());
    instancemanagerbindings.bind(getloader().getclassloader(), getinstancemanager());

  还有:            

 getservletcontext().setattribute(
      jarscanner.class.getname(), getjarscanner());

  合并参数mergeparameters由于我这里是空的,所以什么也没做;然后遍历initializers并onstartup:

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

  先是进入到tomcatstarter的onstartup,这里又是:     

 for (servletcontextinitializer initializer : this.initializers) {
    initializer.onstartup(servletcontext);
   }

  先是执行:   

private org.springframework.boot.web.servlet.servletcontextinitializer getselfinitializer() {
  return new servletcontextinitializer() {
   @override
   public void onstartup(servletcontext servletcontext) throws servletexception {
    selfinitialize(servletcontext);
   }
  };
 }

  embeddedwebapplicationcontext中的selfinitialize ,prepareembeddedwebapplicationcontext正常情况下先打一条日志initializing spring embedded webapplicationcontext然后servletcontext.setattribute(webapplicationcontext.root_web_application_context_attribute, this)然后将this绑定servletcontext,如果启动info级别日志,会打印类似这样的日志:root webapplicationcontext: initialization completed in 3150193 ms;然后new existingwebapplicationscopes,这玩意的注释说它允许与非嵌入式相同的方式注册作用域到applicationcontextinitializer,先执行了一个静态代码块:   

 static {
   set<string> scopes = new linkedhashset<string>();
   scopes.add(webapplicationcontext.scope_request);//request
   scopes.add(webapplicationcontext.scope_session);//session
   scopes.add(webapplicationcontext.scope_global_session);//global session
   scopes = collections.unmodifiableset(scopes);
  }

  但是似乎在我这add白做了,因为构造函数中从bean工厂并没取到scope实例:     

this.beanfactory = beanfactory;
   for (string scopename : scopes) {
    scope scope = beanfactory.getregisteredscope(scopename);
    if (scope != null) {
     this.scopes.put(scopename, scope);
    }
   }

   真正注册作用域是在下一句webapplicationcontextutils.registerwebapplicationscopes(beanfactory, getservletcontext()):  

 beanfactory.registerscope(webapplicationcontext.scope_request, new requestscope());
  beanfactory.registerscope(webapplicationcontext.scope_session, new sessionscope(false));
  beanfactory.registerscope(webapplicationcontext.scope_global_session, new sessionscope(true));
  if (sc != null) {
   servletcontextscope appscope = new servletcontextscope(sc);
   beanfactory.registerscope(webapplicationcontext.scope_application, appscope);
   // register as servletcontext attribute, for contextcleanuplistener to detect it.
   sc.setattribute(servletcontextscope.class.getname(), appscope);
  }
  beanfactory.registerresolvabledependency(servletrequest.class, new requestobjectfactory());
  beanfactory.registerresolvabledependency(servletresponse.class, new responseobjectfactory());
  beanfactory.registerresolvabledependency(httpsession.class, new sessionobjectfactory());
  beanfactory.registerresolvabledependency(webrequest.class, new webrequestobjectfactory());
  if (jsfpresent) {
   facesdependencyregistrar.registerfacesdependencies(beanfactory);
  }

  registerresolvabledependency将类型与对应的装配对象注册进bean工厂。existingscopes.restore里的代码:      

public void restore() {
   for (map.entry<string, scope> entry : this.scopes.entryset()) {
    if (logger.isinfoenabled()) {
     logger.info("restoring user defined scope " + entry.getkey());
    }
    this.beanfactory.registerscope(entry.getkey(), entry.getvalue());
   }
  }

  webapplicationcontextutils.registerenvironmentbeans(beanfactory, getservletcontext())把相应的变量key与值注册给bean工厂,如servletcontext、contextparameters和contextattributes;从bean工厂中获取所有org.springframework.boot.web.servlet.servletcontextinitializer类型的bean,如filterregistrationbean和dispatcherservletregistration然后add给servletcontextinitializerbeans实例的initializers;addadaptablebeans方法先从bean工厂中获取javax.servlet.multipartconfigelement类型的对象,然而javax.servlet.servlet没在bean工厂里找到,所以add什么也没做;javax.servlet.filter找到characterencodingfilter、hiddenhttpmethodfilter、httpputformcontentfilter、requestcontextfilter;servletlistenerregistrationbean.getsupportedtypes()取的是servletlistenerregistrationbean的supported_types,不过全都没找到,所以什么也没做:

 static {
  set<class<?>> types = new hashset<class<?>>();
  types.add(servletcontextattributelistener.class);
  types.add(servletrequestlistener.class);
  types.add(servletrequestattributelistener.class);
  types.add(httpsessionattributelistener.class);
  types.add(httpsessionlistener.class);
  types.add(servletcontextlistener.class);
  supported_types = collections.unmodifiableset(types);
 }

  然后是对找到的进行排序:     

list<servletcontextinitializer> sortedinitializers = new arraylist<servletcontextinitializer>();
  for (map.entry<?, list<servletcontextinitializer>> entry : this.initializers
    .entryset()) {
   annotationawareordercomparator.sort(entry.getvalue());
   sortedinitializers.addall(entry.getvalue());
  }
  this.sortedlist = collections.unmodifiablelist(sortedinitializers);
 public static void sort(object[] array) {
  if (array.length > 1) {
   arrays.sort(array, instance);
  }
 }
 private int docompare(object o1, object o2, ordersourceprovider sourceprovider) {
  boolean p1 = (o1 instanceof priorityordered);
  boolean p2 = (o2 instanceof priorityordered);
  if (p1 && !p2) {
   return -1;
  }
  else if (p2 && !p1) {
   return 1;
  }
  // direct evaluation instead of integer.compareto to avoid unnecessary object creation.
  int i1 = getorder(o1, sourceprovider);
  int i2 = getorder(o2, sourceprovider);
  return (i1 < i2) ? -1 : (i1 > i2) ? 1 : 0;
 }

  然后对这些初始化器进行beans.onstartup(servletcontext);filterregistrationbean执行的abstractfilterregistrationbean的,主要执行了这两句:

        filterregistration.dynamic added = servletcontext.addfilter(name, filter);
                ...
        configure(added);
  name:characterencodingfilter,filter:orderedcharacterencodingfilter,它的配置中这里设定了过滤器转发模式有forward、include、request、async,拦截路径:"/*";然后是hiddenhttpmethodfilter和orderedhiddenhttpmethodfilter,httpputformcontentfilter和orderedhttpputformcontentfilter,requestcontextfilter和orderedrequestcontextfilter,cipherfilter和cipherfilter(我这自定义的)。servletregistrationbean的:dispatcherservlet和dispatcherservlet,asyncsupported是true,url映射是‘/',设置standardwrapper的loadonstartup、 multipartconfigelement。

  到了下一个初始化器sessionconfiguringinitializer:      

 public void onstartup(servletcontext servletcontext) throws servletexception {
   if (this.session.gettrackingmodes() != null) {
    servletcontext.setsessiontrackingmodes(this.session.gettrackingmodes());
   }
   configuresessioncookie(servletcontext.getsessioncookieconfig());
  }

  将session中的cookie信息补充进applicationsessioncookieconfig的实例中,例如:           

 config.setname(cookie.getname());
    config.setdomain(cookie.getdomain());
    config.setpath(cookie.getpath());
    config.setcomment(cookie.getcomment());
    config.sethttponly(cookie.gethttponly());
    config.setsecure(cookie.getsecure());
    config.setmaxage(cookie.getmaxage());

  实际中我这里一个都没执行,因为我这的session中cookie信息都是null。

  下一个初始化器initparameterconfiguringservletcontextinitializer由于参数没有,所以进去就出来了。

  回到listenerstart,listenerstart:org.apache.tomcat.websocket.server.wscontextlistener,用前面的defaultinstancemanager的newinstance创建,然后加到lifecyclelisteners中,然后传给applicationlifecyclelistenersobjects,然后是newservletcontextlistenerallowed=false:当listener发生调用后不允许添加,发布beforecontextinitialized事件,然后wscontextlistener的contextinitialized:    

 servletcontext sc = sce.getservletcontext();
  if(sc.getattribute("javax.websocket.server.servercontainer") == null) {
   wssci.init(sce.getservletcontext(), false);
  }

  init中先是初始化wsservercontainer:  

 static {
  get_bytes = "get ".getbytes(standardcharsets.iso_8859_1);
  root_uri_bytes = "/".getbytes(standardcharsets.iso_8859_1);
  http_version_bytes = " http/1.1\r\n".getbytes(standardcharsets.iso_8859_1);
 }
 static {
  authenticated_http_session_closed = new closereason(closecodes.violated_policy, "this connection was established under an authenticated http session that has ended.");
 }
 wsservercontainer(servletcontext servletcontext) {
  this.enforcenoaddafterhandshake = constants.strict_spec_compliance; //boolean.getboolean("org.apache.tomcat.websocket.strict_spec_compliance")
  this.addallowed = true;
  this.authenticatedsessions = new concurrenthashmap();
  this.endpointsregistered = false;
  this.servletcontext = servletcontext;
   //我这里添加了org.apache.tomcat.websocket.server和本地语言en_us(我代码是在英文版ubuntu上跑的)
  this.setinstancemanager((instancemanager)servletcontext.getattribute(instancemanager.class.getname())); 
  string value = servletcontext.getinitparameter("org.apache.tomcat.websocket.binarybuffersize");
  if(value != null) {
   this.setdefaultmaxbinarymessagebuffersize(integer.parseint(value));
  }
  value = servletcontext.getinitparameter("org.apache.tomcat.websocket.textbuffersize");
  if(value != null) {
   this.setdefaultmaxtextmessagebuffersize(integer.parseint(value));
  }
    //java websocket 规范 1.0 并不允许第一个服务端点开始 websocket 握手之后进行程序性部署。默认情况下,tomcat 继续允许额外的程序性部署。
  value = servletcontext.getinitparameter("org.apache.tomcat.websocket.noaddafterhandshake");
  if(value != null) {
   this.setenforcenoaddafterhandshake(boolean.parseboolean(value));
  }
  dynamic fr = servletcontext.addfilter("tomcat websocket (jsr356) filter", new wsfilter());
  fr.setasyncsupported(true);
  enumset types = enumset.of(dispatchertype.request, dispatchertype.forward);
  fr.addmappingforurlpatterns(types, true, new string[]{"/*"});
 }

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

  init创建了 wsservercontainer之后,将它设置给servletcontext的javax.websocket.server.servercontainer属性,然后servletcontext.addlistener(new wssessionlistener(sc))加进前面的applicationlifecyclelistenersobjects中,init结束,回到standardcontext发布aftercontextinitialized事件,我这到这里listenerstart结束。

  checkconstraintsforuncoveredmethods(findconstraints())因为我这里find出来的并没有,所以pass;start standardmanager startinternal先是super(managerbase),一进方法先是将两个双端队列sessioncreationtiming和sessionexpirationtiming根据常量timing_stats_cache_size用null填满,设置jvmroute(jvmroute用于区分多tomcat节点,根据jvmroute的值来确定当前会话属于哪个节点 ),从engine上取得,之前设置过,getengine: 

 public engine getengine() {
  engine e = null;
  for (container c = getcontext(); e == null && c != null ; c = c.getparent()) {
   if (c instanceof engine) {
    e = (engine)c;
   }
  }
  return e;
 }

  set给sessionidgenerator,将之前初始化过的一些sessionidgenerator值set给新new的sessionidgeneratorbase,然后start之前的sessionidgenerator,这个start没做什么特别的,于是回到standardmanager,加载文件(例:/tmp/tomcat.7550276477249965168.80/work/tomcat/localhost/root/sessions.ser),用于session持久化的,这时候找不到的。

  filterstart对filterconfigs同步锁,filterconfigs.put(name, filterconfig):

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

  loadonstartup(findchildren()),其实都一起start过了就不用了:

Spring Boot启动过程(六)之内嵌Tomcat中StandardHost、StandardContext和StandardWrapper的启动教程详解

   该启动standardcontext的后天线程了super.threadstart(),当然因为backgroundprocessordelay所以也没启,unbindthread说是解绑,其实只是把classloader还原了,别的没做什么,对应着之前的bind。

  设置standardcontext的starttime=system.currenttimemillis(),发j2ee.state.running的通知,objectname是tomcat:j2eeapplication=none, j2eeserver=none, j2eetype=webmodule, name=//localhost/;getresources().gc()因为webresources引用了一些jar,有些平台可能会对jar加锁,这里先清理,但实际上这里的实现是空的。

   disablepersistsessionlistener由于并没有配置session持久化,所以会触发这个监听器,实际只执行了((standardmanager) manager).setpathname(null)。memoryleaktrackinglistener只走了个过场。

   发布after_start事件,这回终于执行了memoryleaktrackinglistener:      

 if (event.gettype().equals(lifecycle.after_start_event)) {
    if (event.getsource() instanceof context) {
     context context = ((context) event.getsource());
     childclassloaders.put(context.getloader().getclassloader(),
       context.getservletcontext().getcontextpath());
    }
   }

  子容器就启动完成了。

咱最近用的github:

以上所述是小编给大家介绍的spring boot启动过程(六)之内嵌tomcat中standardhost、standardcontext和standardwrapper的启动教程详解,希望对大家有所帮助