Poison

本地使用 IDEA 编译调试 Tomcat 代码

发表于

由于有时需要验证 Tomcat 的问题或者调试其内部代码，所以需要在本地 IDEA 搭建 Tomcat 的开发环境，在此简单记录。

整个过程根据官方的构建文档调整而来，参考：Apache Tomcat 8 (8.5.70) - Building Tomcat。

首先确认机器安装了 Java SE Development Kit 8 及 Apache Ant，我本地使用的版本是 JDK 1.8.0_291 及 Ant 1.10.8_1。

从 GitHub 上 clone Apache Tomcat 的源码：

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git clone https://github.com/apache/tomcat.git

clone 完成后切换到 tomcat 工程目录并切换到指定的 tag，我使用 8.5.70：

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cd tomcat
git checkout 8.5.70

先使用 ant 构建一次，把缺失的 jar 下载到本地：

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ant

再使用 ant 生成 Intellij IDEA 所需的项目环境信息：

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ant ide-intellij

部分输出如下：

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downloadfile:
      [get] Getting: https://repo.maven.apache.org/maven2/com/unboundid/unboundid-ldapsdk/6.0.0/unboundid-ldapsdk-6.0.0.jar
      [get] To: /Users/Poison/tomcat-build-libs/download-588515216.tmp
     [echo] Checksum check for unboundid-ldapsdk-6.0.0.jar, algorithm MD5|SHA-1: OK
    [mkdir] Created dir: /Users/Poison/tomcat-build-libs/unboundid-6.0.0
     [move] Moving 1 file to /Users/Poison/tomcat-build-libs/unboundid-6.0.0

ide-intellij:
     [copy] Copying 10 files to /Users/Poison/IdeaProjects/tomcat/.idea
     [echo] IntelliJ IDEA project directory created. Please create PATH VARIABLES for
     [echo]
     [echo]       ANT_HOME          = /usr/local/Cellar/ant/1.10.8_1/libexec
     [echo]       TOMCAT_BUILD_LIBS = /Users/Poison/tomcat-build-libs
     [echo]

BUILD SUCCESSFUL
Total time: 53 seconds

可以看到 Intellij IDEA 项目所需的 .idea 目录已经生成，此时我们使用 Intellij IDEA 打开该目录，根据文档配置以上两个 PATH VARIABLES，配置 PATH VARIABLES 的文档可以参考：Path variables | IntelliJ IDEA，在我的电脑上配置后的截图如下：
PATH VARIABLES

然后在 IDEA 中从类入口 org.apache.catalina.startup.Bootstrap#main 运行 Tomcat，随即发现编译报错：

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/Users/Poison/IdeaProjects/tomcat/test/util/TestCookieFilter.java:19:17
java: package org.junit does not exist

原因为 tag 为 8.5.70 的 ant target: ide-intellij 中使用的 JUnit 版本为 4.13，而 Tomcat 实际使用的 JUnit 版本已经升级至 4.13.2，且 TOMCAT_BUILD_LIBS 对应的目录下的 JUnit 版本也是 4.13.2，所以我们需要手动修改 IDEA 中使用的 JUnit 版本，在 .idea/tomtat.iml 中调整 JUnit 的版本：

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<orderEntry type="module-library">
  <library>
    <CLASSES>
        <root url="jar://$TOMCAT_BUILD_LIBS$/junit-4.13/junit-4.13.jar!/" />
    </CLASSES>
    <JAVADOC />
    <SOURCES />
  </library>
</orderEntry>

将其中的 jar://$TOMCAT_BUILD_LIBS$/junit-4.13/junit-4.13.jar!/ 替换为 jar://$TOMCAT_BUILD_LIBS$/junit-4.13.2/junit-4.13.2.jar!/ 后重新运行 org.apache.catalina.startup.Bootstrap#main，我的电脑的启动输出日志如下：

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Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.ClassLoaderFactory validateFile
WARNING: Problem with directory [/Users/Poison/IdeaProjects/tomcat/lib], exists: [false], isDirectory: [false], canRead: [false]
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.ClassLoaderFactory validateFile
WARNING: Problem with directory [/Users/Poison/IdeaProjects/tomcat/lib], exists: [false], isDirectory: [false], canRead: [false]
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.ClassLoaderFactory validateFile
WARNING: Problem with directory [/Users/Poison/IdeaProjects/tomcat/lib], exists: [false], isDirectory: [false], canRead: [false]
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.ClassLoaderFactory validateFile
WARNING: Problem with directory [/Users/Poison/IdeaProjects/tomcat/lib], exists: [false], isDirectory: [false], canRead: [false]
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server version name:   Apache Tomcat/@VERSION@
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server built:          @VERSION_BUILT@
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server version number: @VERSION_NUMBER@
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: OS Name:               Mac OS X
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: OS Version:            10.16
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Architecture:          x86_64
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Java Home:             /Library/Java/JavaVirtualMachines/jdk1.8.0_291.jdk/Contents/Home/jre
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: JVM Version:           1.8.0_291-b10
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: JVM Vendor:            Oracle Corporation
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: CATALINA_BASE:         /Users/Poison/IdeaProjects/tomcat
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: CATALINA_HOME:         /Users/Poison/IdeaProjects/tomcat
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -javaagent:/Applications/IntelliJ IDEA.app/Contents/lib/idea_rt.jar=62955:/Applications/IntelliJ IDEA.app/Contents/bin
Aug 26, 2021 5:26:33 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dfile.encoding=UTF-8
Aug 26, 2021 5:26:33 PM org.apache.catalina.core.AprLifecycleListener lifecycleEvent
INFO: The Apache Tomcat Native library which allows using OpenSSL was not found on the java.library.path: [/Users/Poison/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
Aug 26, 2021 5:26:33 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-nio-8080"]
Aug 26, 2021 5:26:34 PM org.apache.tomcat.util.net.NioSelectorPool getSharedSelector
INFO: Using a shared selector for servlet write/read
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 683 ms
Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service [Catalina]
Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet engine: [Apache Tomcat/@VERSION@]
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/docs]
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/docs] has finished in [350] ms
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/manager]
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/manager] has finished in [66] ms
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/examples]
Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Error configuring application listener of class [listeners.ContextListener]
java.lang.ClassNotFoundException: listeners.ContextListener
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1415)
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1223)
 at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:537)
 at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:518)
 at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:149)
 at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4686)
 at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5232)
 at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:753)
 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:727)
 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:695)
 at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1177)
 at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1925)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
 at java.util.concurrent.FutureTask.run(FutureTask.java:266)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 at java.lang.Thread.run(Thread.java:748)

Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Error configuring application listener of class [listeners.SessionListener]
java.lang.ClassNotFoundException: listeners.SessionListener
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1415)
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1223)
 at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:537)
 at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:518)
 at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:149)
 at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4686)
 at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5232)
 at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:753)
 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:727)
 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:695)
 at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1177)
 at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1925)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
 at java.util.concurrent.FutureTask.run(FutureTask.java:266)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 at java.lang.Thread.run(Thread.java:748)

Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Error configuring application listener of class [async.AsyncStockContextListener]
java.lang.ClassNotFoundException: async.AsyncStockContextListener
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1415)
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1223)
 at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:537)
 at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:518)
 at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:149)
 at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4686)
 at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5232)
 at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:753)
 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:727)
 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:695)
 at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1177)
 at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1925)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
 at java.util.concurrent.FutureTask.run(FutureTask.java:266)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 at java.lang.Thread.run(Thread.java:748)

Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Error configuring application listener of class [websocket.drawboard.DrawboardContextListener]
java.lang.ClassNotFoundException: websocket.drawboard.DrawboardContextListener
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1415)
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1223)
 at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:537)
 at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:518)
 at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:149)
 at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4686)
 at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5232)
 at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:753)
 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:727)
 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:695)
 at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1177)
 at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1925)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
 at java.util.concurrent.FutureTask.run(FutureTask.java:266)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 at java.lang.Thread.run(Thread.java:748)

Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Skipped installing application listeners due to previous error(s)
Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: One or more listeners failed to start. Full details will be found in the appropriate container log file
Aug 26, 2021 5:26:34 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/examples] startup failed due to previous errors
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/examples] has finished in [94] ms
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/ROOT]
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/ROOT] has finished in [92] ms
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/host-manager]
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory [/Users/Poison/IdeaProjects/tomcat/webapps/host-manager] has finished in [92] ms
Aug 26, 2021 5:26:34 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8080"]
Aug 26, 2021 5:26:34 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 875 ms

看起来好像出错了，是 webapps/examples 目录引起的，查看该目录下的内容，原来是原生的 Java 类，没有进行编译，而之前我们执行的 ant 编译出的目录位于 output/build/webapps，所以我们对源码进行简单的调整以处理本地环境使用的 webapps 目录不正确的问题：

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// 将 org.apache.catalina.core.StandardHost#getAppBaseFile 中的代码进行调整，调整前：
File file = new File(getAppBase());
// 调整后
File file = new File("output/build/" + getAppBase());

调整完成后，启动不再报错，就可以 DEBUG 源码了。