上篇分析到HostConfig的入口方法：lifeCycleEvent
setCopyXML(((StandardHost) host).isCopyXML());//是否发布xml文件的标识，默认为true
setDeployXML(((StandardHost) host).isDeployXML());;//是否动态部署标识，默认为true
setUnpackWARs(((StandardHost) host).isUnpackWARs());//是否要将war文件解压缩，默认为true
setContextClass(((StandardHost) host).getContextClass());检查webapps和conf/localhost文件夹是否存在
- 检查是否文件夹：C:\workspace\Tomcat9\webapps；判断为否则DeployOnStartup，AutoDeploy设置为false
- DeployOnStartup=true，则调用deployApps
//根目录下/weapps eg:C:\workspace\Tomcat9\webapps
File appBase = host.getAppBaseFile();
//根目录下/conf/Catalina/localhost eg:C:\workspace\Tomcat9\conf\Catalina\localhost
File configBase = host.getConfigBaseFile();
String[] filteredAppPaths = filterAppPaths(appBase.list());
// Deploy XML descriptors from configBase
deployDescriptors(configBase, configBase.list());//通过描述符发布应用
// Deploy WARs
deployWARs(appBase, filteredAppPaths);//发布war文件的应用
// Deploy expanded folders
deployDirectories(appBase, filteredAppPaths);//发布目录型的应用 在deployDirectory部署阶段会反射调用StandardContext，并且在往StandardHost中addChild时会触发Context的init，start等操作。
以下章节重点分析web应用程序(context)的加载：
主要步骤
- 查找C:\workspace\Tomcat9\conf\Catalina\localhost下所有xml文件组织成ContextName
- 开线程调用hostconfig的deployDescriptor方法，该方法会调用digester解析该文件，生成StandardContext
- 初始化StandardContext，设置相关属性及监听器
- 当该文件的DocBase属性不为null时
/**
configBase:C:\workspace\Tomcat9\conf\Catalina\localhost
files:xxxx.xml
**/
protected void deployDescriptors(File configBase, String[] files) {
if (files == null)
return;
ExecutorService es = host.getStartStopExecutor();
List<Future<?>> results = new ArrayList<>();
for (int i = 0; i < files.length; i++) {
File contextXml = new File(configBase, files[i]);
//判断是否后缀为.xml
if (files[i].toLowerCase(Locale.ENGLISH).endsWith(".xml")) {
ContextName cn = new ContextName(files[i], true);
if (isServiced(cn.getName()) || deploymentExists(cn.getName()))
continue;
//开线程启动DeployDescriptor对象
results.add(es.submit(new DeployDescriptor(this, cn, contextXml)));
}
}
for (Future<?> result : results) {
try {
result.get();
} catch (Exception e) {
log.error(sm.getString(
"hostConfig.deployDescriptor.threaded.error"), e);
}
}
}
具体代码如下：
public ContextName(String name, boolean stripFileExtension) {
String tmp1 = name;
//如果/xx.xml，则转换为xx.xml
if (tmp1.startsWith("/")) {
tmp1 = tmp1.substring(1);
}
// 把所有的/替换为#，如xx/yy/zz.xml-->xx#yy#zz.xml
tmp1 = tmp1.replaceAll("/", FWD_SLASH_REPLACEMENT);
//1.##xx.xml-->Root##xx.xml
//2./.xml----->Root.xml
if (tmp1.startsWith(VERSION_MARKER) || "".equals(tmp1)) {
tmp1 = ROOT_NAME + tmp1;
}
// stripFileExtension=true时，后缀名截断
if (stripFileExtension &&
(tmp1.toLowerCase(Locale.ENGLISH).endsWith(".war") ||
tmp1.toLowerCase(Locale.ENGLISH).endsWith(".xml"))) {
tmp1 = tmp1.substring(0, tmp1.length() -4);
}
baseName = tmp1;
//获取版本信息
String tmp2;
int versionIndex = baseName.indexOf(VERSION_MARKER);
if (versionIndex > -1) {
version = baseName.substring(versionIndex + 2);
tmp2 = baseName.substring(0, versionIndex);
} else {
version = "";
tmp2 = baseName;
}
if (ROOT_NAME.equals(tmp2)) {
path = "";
} else {
path = "/" + tmp2.replaceAll(FWD_SLASH_REPLACEMENT, "/");
}
//name：path+#+版本号
if (versionIndex > -1) {
this.name = path + VERSION_MARKER + version;
} else {
this.name = path;
}
}ContextName的构造函数会对传入的xx.xml进行分析截取，具体步骤如下：
- 如果xml文件以为
/开头，则去除/ - 把所有的
/都替换成#
步骤1.2在windows上其实是多余的。因为新建文件时会报以下错误：“文件名不能包含下列任何字符：/:*?"<>|”
- 如果文件以
##开头，则替换为ROOT+文件名;（即如果含有版本号但没有名称，则认为是root的分支版本） 如果文件为空,则替换为Root.xml - 根据需要截断后缀名
- 经过以上4个步骤生成的xml文件名赋值给
baseName(baseName是含有版本号的字符串) - 如果
baseName中含有##,则##之后的字符串作为版本号(version)，之前的的字符串作为tmp2 - 如果
tmp2等于ROOT，则path="",否则path=/+tmp2将所有#替换为/后的字符串 version不为空时：name等于path+##+version；否则name等于path
protected void deployDescriptor(ContextName cn, File contextXml) {
DeployedApplication deployedApp =
new DeployedApplication(cn.getName(), true);
long startTime = 0;
// Assume this is a configuration descriptor and deploy it
if(log.isInfoEnabled()) {
startTime = System.currentTimeMillis();
log.info(sm.getString("hostConfig.deployDescriptor",
contextXml.getAbsolutePath()));
}
Context context = null;
boolean isExternalWar = false;
boolean isExternal = false;
File expandedDocBase = null;
try (FileInputStream fis = new FileInputStream(contextXml)) {
//采用digester解析xml文件
synchronized (digesterLock) {
try {
context = (Context) digester.parse(fis);
} catch (Exception e) {
log.error(sm.getString(
"hostConfig.deployDescriptor.error",
contextXml.getAbsolutePath()), e);
} finally {
digester.reset();
if (context == null) {
context = new FailedContext();
}
}
}
//为context对象添加contextConfig监听器
Class<?> clazz = Class.forName(host.getConfigClass());
LifecycleListener listener =
(LifecycleListener) clazz.newInstance();
context.addLifecycleListener(listener);
//根据xml配置context相关属性
//注意path属性采用的是ContextName的值，而ContextName的path是由xml文件的名称决定的，即<Context path='/XX'>会被该文件的名称所替换，
context.setConfigFile(contextXml.toURI().toURL());
context.setName(cn.getName());
context.setPath(cn.getPath());
context.setWebappVersion(cn.getVersion());
// 如果xml中docBase属性不为空
if (context.getDocBase() != null) {
File docBase = new File(context.getDocBase());
//如果是相对地址，则采用当前主机路径
if (!docBase.isAbsolute()) {
docBase = new File(host.getAppBaseFile(), context.getDocBase());
}
// 如果<Context docBase="D:/example />中的路径不是在host路径中
if (!docBase.getCanonicalPath().startsWith(
host.getAppBaseFile().getAbsolutePath() + File.separator)) {
//标志为外部项目
isExternal = true;
deployedApp.redeployResources.put(
contextXml.getAbsolutePath(),
Long.valueOf(contextXml.lastModified()));
deployedApp.redeployResources.put(docBase.getAbsolutePath(),
Long.valueOf(docBase.lastModified()));
if (docBase.getAbsolutePath().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
isExternalWar = true;
}
} else {
log.warn(sm.getString("hostConfig.deployDescriptor.localDocBaseSpecified",
docBase));
// Ignore specified docBase
context.setDocBase(null);
}
}
//将web项目添加到host中，此处会触发context的init-->start；而init、start之前又会触发conextConfig的事件响应
host.addChild(context);
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
log.error(sm.getString("hostConfig.deployDescriptor.error",
contextXml.getAbsolutePath()), t);
} finally {
// Get paths for WAR and expanded WAR in appBase
// default to appBase dir + name
expandedDocBase = new File(host.getAppBaseFile(), cn.getBaseName());
if (context.getDocBase() != null
&& !context.getDocBase().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
// first assume docBase is absolute
expandedDocBase = new File(context.getDocBase());
if (!expandedDocBase.isAbsolute()) {
// if docBase specified and relative, it must be relative to appBase
expandedDocBase = new File(host.getAppBaseFile(), context.getDocBase());
}
}
boolean unpackWAR = unpackWARs;
if (unpackWAR && context instanceof StandardContext) {
unpackWAR = ((StandardContext) context).getUnpackWAR();
}
// Add the eventual unpacked WAR and all the resources which will be
// watched inside it
if (isExternalWar) {
if (unpackWAR) {
deployedApp.redeployResources.put(expandedDocBase.getAbsolutePath(),
Long.valueOf(expandedDocBase.lastModified()));
addWatchedResources(deployedApp, expandedDocBase.getAbsolutePath(), context);
} else {
addWatchedResources(deployedApp, null, context);
}
} else {
// Find an existing matching war and expanded folder
if (!isExternal) {
File warDocBase = new File(expandedDocBase.getAbsolutePath() + ".war");
if (warDocBase.exists()) {
deployedApp.redeployResources.put(warDocBase.getAbsolutePath(),
Long.valueOf(warDocBase.lastModified()));
} else {
// Trigger a redeploy if a WAR is added
deployedApp.redeployResources.put(
warDocBase.getAbsolutePath(),
Long.valueOf(0));
}
}
if (unpackWAR) {
deployedApp.redeployResources.put(expandedDocBase.getAbsolutePath(),
Long.valueOf(expandedDocBase.lastModified()));
addWatchedResources(deployedApp,
expandedDocBase.getAbsolutePath(), context);
} else {
addWatchedResources(deployedApp, null, context);
}
if (!isExternal) {
// For external docBases, the context.xml will have been
// added above.
deployedApp.redeployResources.put(
contextXml.getAbsolutePath(),
Long.valueOf(contextXml.lastModified()));
}
}
// Add the global redeploy resources (which are never deleted) at
// the end so they don't interfere with the deletion process
addGlobalRedeployResources(deployedApp);
}
//加入到deployed，表示已加载完成的应用程序。
if (host.findChild(context.getName()) != null) {
deployed.put(context.getName(), deployedApp);
}
if (log.isInfoEnabled()) {
log.info(sm.getString("hostConfig.deployDescriptor.finished",
contextXml.getAbsolutePath(), Long.valueOf(System.currentTimeMillis() - startTime)));
}
}- 忽略所有META-INF、WEB-INF命名的文件夹
- 查找C:\workspace\Tomcat9下所有.war包
- 其他和deployDescriptor相同
host主要聚焦于context的加载，初始化、启动，下面继续分析Context对象