本系列轉(zhuǎn)載自?http://blog.csdn.net/haitao111313/article/category/1179996?

? 我們知道，在Tomcat的世界里，一個(gè)Host容器代表一個(gè)虛機(jī)器資源，Context容器代表一個(gè)應(yīng)用，所謂的部署器就是能夠把Context容器添加進(jìn)Host容器中去的一個(gè)組件。顯然，一個(gè)Host容器應(yīng)該擁有一個(gè)部署器組件。簡(jiǎn)單的部署代碼應(yīng)該是下面這樣的：

[java]?view plaincopyprint?

Context?context?=?new?StandardContext();??

Host?host?=?new?StandardHost();??

host.addChild(context);??

別看這簡(jiǎn)單，其實(shí)這就是核心的部署代碼。當(dāng)然，Tomcat的部署器絕不是這么點(diǎn)東西，但其實(shí)也是比較簡(jiǎn)單的東西。在Catalina的createStartDigester()方法中（具體怎么調(diào)用到這個(gè)方法，詳細(xì)參考Tomcat源碼分析(一)--服務(wù)啟動(dòng)），向StandardHost容器中添加了一個(gè)HostConfig的實(shí)例。HostConfig類實(shí)現(xiàn)了LifecycleListener接口，也就是說(shuō)它是個(gè)監(jiān)聽器類，能監(jiān)聽到組件的生命周期事件（有關(guān)生命周期的東西請(qǐng)參看Tomcat源碼分析(七)--單一啟動(dòng)/關(guān)閉機(jī)制(生命周期)）。? 下面看接受事件的方法lifecycleEvent(LifecycleEvent)做了寫什么工作：

[java]?view plaincopyprint?

public?void?lifecycleEvent(LifecycleEvent?event)?{??

??

????????//?Identify?the?host?we?are?associated?with??

????????try?{??

????????????host?=?(Host)?event.getLifecycle();??

????????????if?(host?instanceof?StandardHost)?{?//如果監(jiān)聽到的事件對(duì)象類型是StandardHost就設(shè)置相關(guān)屬性。??

????????????????int?hostDebug?=?((StandardHost)?host).getDebug();??

????????????????if?(hostDebug?>?this.debug)?{??

????????????????????this.debug?=?hostDebug;??

????????????????}??

????????????????setDeployXML(((StandardHost)?host).isDeployXML());//是否發(fā)布xml文件的標(biāo)識(shí)，默認(rèn)為true??

????????????????setLiveDeploy(((StandardHost)?host).getLiveDeploy());//是否動(dòng)態(tài)部署標(biāo)識(shí)，默認(rèn)為true??

????????????????setUnpackWARs(((StandardHost)?host).isUnpackWARs());//是否要將war文件解壓縮，默認(rèn)為true??

????????????}??

????????}?catch?(ClassCastException?e)?{??

????????????log(sm.getString("hostConfig.cce",?event.getLifecycle()),?e);??

????????????return;??

????????}??

??

????????//?Process?the?event?that?has?occurred??

????????if?(event.getType().equals(Lifecycle.START_EVENT))?//監(jiān)聽到容器開始，則調(diào)用start方法，方法里面調(diào)用了部署應(yīng)用的代碼??

????????????start();??

????????else?if?(event.getType().equals(Lifecycle.STOP_EVENT))??

????????????stop();??

??

????}??

如果監(jiān)聽到StandardHost容器啟動(dòng)開始了，則調(diào)用start方法來(lái)，下面看start方法：

[java]?view plaincopyprint?

protected?void?start()?{??

??

???????if?(debug?>=?1)??

???????????log(sm.getString("hostConfig.start"));??

??

???????if?(host.getAutoDeploy())?{??

???????????deployApps();//發(fā)布應(yīng)用??

???????}??

??

???????if?(isLiveDeploy())?{??

???????????threadStart();//動(dòng)態(tài)發(fā)布應(yīng)用，因?yàn)镠ostConfig也實(shí)現(xiàn)了Runnable接口，threadStart啟動(dòng)該線程來(lái)實(shí)現(xiàn)動(dòng)態(tài)發(fā)布??

???????}??

??

???}??

??--------------------》deployApps方法，該方法會(huì)把webapps目錄下的所有目錄都看作成一個(gè)應(yīng)用程序??

????protected?void?deployApps()?{??

??

???????if?(!(host?instanceof?Deployer))??

???????????return;??

???????if?(debug?>=?1)??

???????????log(sm.getString("hostConfig.deploying"));??

??

???????File?appBase?=?appBase();//返回webapps目錄??

???????if?(!appBase.exists()?||?!appBase.isDirectory())??

???????????return;??

???????String?files[]?=?appBase.list();//列出webapps目錄下的所有文件??

??

???????deployDescriptors(appBase,?files);//通過描述符發(fā)布應(yīng)用??

???????deployWARs(appBase,?files);//發(fā)布war文件的應(yīng)用??

???????deployDirectories(appBase,?files);//發(fā)布目錄型的應(yīng)用??

??

???}??

以上三個(gè)發(fā)布應(yīng)用的方式大同小異，所以只說(shuō)說(shuō)常用的發(fā)布方式--目錄型的應(yīng)用，下面看看deployDirectories方法，只寫了關(guān)鍵的邏輯：

[java]?view plaincopyprint?

protected?void?deployDirectories(File?appBase,?String[]?files)?{??

??

?????for?(int?i?=?0;?i?<?files.length;?i++)?{??

??

?????????if?(files[i].equalsIgnoreCase("META-INF"))??

?????????????continue;??

?????????if?(files[i].equalsIgnoreCase("WEB-INF"))??

?????????????continue;??

?????????if?(deployed.contains(files[i]))??

?????????????continue;??

?????????File?dir?=?new?File(appBase,?files[i]);??

?????????if?(dir.isDirectory())?{??

??

?????????????deployed.add(files[i]);??

??

?????????????//?Make?sure?there?is?an?application?configuration?directory??

?????????????//?This?is?needed?if?the?Context?appBase?is?the?same?as?the??

?????????????//?web?server?document?root?to?make?sure?only?web?applications??

?????????????//?are?deployed?and?not?directories?for?web?space.??

?????????????File?webInf?=?new?File(dir,?"/WEB-INF");??

?????????????if?(!webInf.exists()?||?!webInf.isDirectory()?||??

?????????????????!webInf.canRead())??

?????????????????continue;??

??

?????????????//?Calculate?the?context?path?and?make?sure?it?is?unique??

?????????????String?contextPath?=?"/"?+?files[i];??

?????????????if?(files[i].equals("ROOT"))??

?????????????????contextPath?=?"";??

?????????????if?(host.findChild(contextPath)?!=?null)??

?????????????????continue;??

??

?????????????//?Deploy?the?application?in?this?directory??

?????????????log(sm.getString("hostConfig.deployDir",?files[i]));??

?????????????try?{??

?????????????????URL?url?=?new?URL("file",?null,?dir.getCanonicalPath());//得到應(yīng)用的路徑，路徑的寫法是???file://應(yīng)用名稱??

?????????????????((Deployer)?host).install(contextPath,?url);?//安裝應(yīng)用到目錄下??

?????????????}?catch?(Throwable?t)?{??

?????????????????log(sm.getString("hostConfig.deployDir.error",?files[i]),??

?????????????????????t);??

?????????????}??

??

?????????}??

??

?????}??

??

?}??

((Deployer) host).install(contextPath, url);會(huì)調(diào)用到StandardHost的install方法，再由StandardHost轉(zhuǎn)交給StandardHostDeployer的install方法，StandardHostDeployer是一個(gè)輔助類，幫助StandardHost來(lái)實(shí)現(xiàn)發(fā)布應(yīng)用，它實(shí)現(xiàn)了Deployer接口，看它的install(URL config, URL war)方法（它有兩個(gè)install方法，分別用來(lái)發(fā)布上面不同方式的應(yīng)用）：

[java]?view plaincopyprint?

public?synchronized?void?install(String?contextPath,?URL?war)??

???????throws?IOException?{??

??

?????..............................................??

??

???????//?Calculate?the?document?base?for?the?new?web?application??

???????host.log(sm.getString("standardHost.installing",??

?????????????????????????????contextPath,?war.toString()));??

???????String?url?=?war.toString();??

???????String?docBase?=?null;??

???????if?(url.startsWith("jar:"))?{???//如果是war類型的應(yīng)用??

???????????url?=?url.substring(4,?url.length()?-?2);??

???????}??

???????if?(url.startsWith("file://"))//如果是目錄類型的應(yīng)用??

???????????docBase?=?url.substring(7);??

???????else?if?(url.startsWith("file:"))??

???????????docBase?=?url.substring(5);??

???????else??

???????????throw?new?IllegalArgumentException??

???????????????(sm.getString("standardHost.warURL",?url));??

??

???????//?Install?the?new?web?application??

???????try?{??

???????????Class?clazz?=?Class.forName(host.getContextClass());//host.getContextClass得到的其實(shí)是StandardContext，??

???????????Context?context?=?(Context)?clazz.newInstance();??

???????????context.setPath(contextPath);//設(shè)置該context的訪問路徑為contextPath，即我們的應(yīng)用訪問路徑??

?????????????

???????????context.setDocBase(docBase);//設(shè)置該應(yīng)用在磁盤的路徑??

???????????if?(context?instanceof?Lifecycle)?{??

???????????????clazz?=?Class.forName(host.getConfigClass());//實(shí)例化host的監(jiān)聽器類，并關(guān)聯(lián)上context??

???????????????LifecycleListener?listener?=??

???????????????????(LifecycleListener)?clazz.newInstance();??

???????????????((Lifecycle)?context).addLifecycleListener(listener);??

???????????}??

???????????host.fireContainerEvent(PRE_INSTALL_EVENT,?context);??

???????????host.addChild(context);???????????//添加到host實(shí)例，即把context應(yīng)用發(fā)布到host。??

???????????host.fireContainerEvent(INSTALL_EVENT,?context);??

???????}?catch?(Exception?e)?{??

???????????host.log(sm.getString("standardHost.installError",?contextPath),??

????????????????????e);??

???????????throw?new?IOException(e.toString());??

???????}??

??

???}??

經(jīng)過上面的代碼分析，已經(jīng)完全了解了怎么發(fā)布一個(gè)目錄型的應(yīng)用到StandardHost中，其他war包和文件描述符類型的應(yīng)用發(fā)布跟StandardHost大體類似，在這里就不說(shuō)了，有興趣的可以自己查看源代碼。

轉(zhuǎn)載于:https://www.cnblogs.com/chenying99/archive/2012/12/02/2798452.html

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