tomcat 编译

Posted on:November 30, 2022 at 10:37 PM

背景

了解tomcat生命周期，了解一个http的生命周期

步骤

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

相关的编译后的安装目录在${tomcat.source}/build.propertiesfile 里面

我的是ubuntu所以直接通过包管理安装

sudo apt install ant

cp build.properties.default  build.properties

我们需要将调试符号编译时生成，如果是一个java程序，则是javac -g , 也就是在编译的时候添加到javac 中. 在tomcat的源代码中的build.xml 中很容易看到compile.debug 这个环境变量

<javac srcdir="java" destdir="${tomcat.classes}"
           debug="${compile.debug}"                      <--!     这里会有compile.debug 环境变量 ->
           deprecation="${compile.deprecation}"
           release="${compile.release}"
           encoding="ISO-8859-1"
           includeAntRuntime="true" >
      <!-- Uncomment this to show unchecked warnings:
      <compilerarg value="-Xlint:unchecked"/>

那么这个环境变量是在哪里控制的呢？ 打开 build.properties ,就能看到，所以默认下载下来的tomcat 就是开了-g 选项的，不需要修改

# ----- Build control flags -----
compile.debug=true
ant

编译好的相关代码会在 , source_code 就是你的源代码

{source_code}/output/build/bin

切换目录到{source_code}/output/build/bin

./startup.sh 
Using CATALINA_BASE:   /home/dai/tomcat/output/build
Using CATALINA_HOME:   /home/dai/tomcat/output/build
Using CATALINA_TMPDIR: /home/dai/tomcat/output/build/temp
Using JRE_HOME:        /usr
Using CLASSPATH:       /home/dai/tomcat/output/build/bin/bootstrap.jar:/home/dai/tomcat/output/build/bin/tomcat-juli.jar
Using CATALINA_OPTS:   
Tomcat started.

查看tomcat 的命令 ， 就是以下内容：

ps aux | grep tomcat


/usr/bin/java -Djava.util.logging.config.file=/home/dai/tomcat/output/build/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED -classpath /home/dai/tomcat/output/build/bin/bootstrap.jar:/home/dai/tomcat/output/build/bin/tomcat-juli.jar -Dcatalina.base=/home/dai/tomcat/output/build -Dcatalina.home=/home/dai/tomcat/output/build -Djava.io.tmpdir=/home/dai/tomcat/output/build/temp org.apache.catalina.startup.Bootstrap start

请求tomcat

在浏览器输入 http://127.0.0.1:8080/

debug tomcat

断点到main函数

在上面步骤用ps aux | grep "tomcat" 获取执行的命令 ， 然后在前面/usr/bin/java 紧接着的地方加上参数-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=8000 ,让程序断点在main函数

参数说明：

/usr/bin/java -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=8000   -Djava.util.logging.config.file=/home/dai/tomcat/output/build/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED -classpath /home/dai/tomcat/output/build/bin/bootstrap.jar:/home/dai/tomcat/output/build/bin/tomcat-juli.jar -Dcatalina.base=/home/dai/tomcat/output/build -Dcatalina.home=/home/dai/tomcat/output/build -Djava.io.tmpdir=/home/dai/tomcat/output/build/temp org.apache.catalina.startup.Bootstrap start

jdb 开启调试

jdb  -attach  8000 -sourcepath /home/dai/tomcat/java/

### 在  org.apache.catalina.startup.Bootstrap.main 打断点
main[1] stop in   org.apache.catalina.startup.Bootstrap.main
Deferring breakpoint org.apache.catalina.startup.Bootstrap.main.
It will be set after the class is loaded.
#### 使用run开始执行
main[1] run

使用list 列出代码 然后就会断点到main 函数

Breakpoint hit: "thread=main", org.apache.catalina.startup.Bootstrap.main(), line=442 bci=0
442            synchronized (daemonLock) {

main[1] list
438         * @param args Command line arguments to be processed
439         */
440        public static void main(String args[]) {
441    
442 =>         synchronized (daemonLock) {
443                if (daemon == null) {
444                    // Don't set daemon until init() has completed
445                    Bootstrap bootstrap = new Bootstrap();
446                    try {
447                        bootstrap.init();
main[1]

servelet 请求路径

http-nio-8080-exec-1[1] where
  [1] HelloWorldExample.doGet (HelloWorldExample.java:41)
  [2] jakarta.servlet.http.HttpServlet.service (HttpServlet.java:705)
  [3] jakarta.servlet.http.HttpServlet.service (HttpServlet.java:814)
  [4] org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (ApplicationFilterChain.java:223)
  [5] org.apache.catalina.core.ApplicationFilterChain.doFilter (ApplicationFilterChain.java:158)
  [6] org.apache.tomcat.websocket.server.WsFilter.doFilter (WsFilter.java:53)
  [7] org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (ApplicationFilterChain.java:185)
  [8] org.apache.catalina.core.ApplicationFilterChain.doFilter (ApplicationFilterChain.java:158)
  [9] org.apache.catalina.filters.HttpHeaderSecurityFilter.doFilter (HttpHeaderSecurityFilter.java:126)
  [10] org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (ApplicationFilterChain.java:185)
  [11] org.apache.catalina.core.ApplicationFilterChain.doFilter (ApplicationFilterChain.java:158)
  [12] org.apache.catalina.core.StandardWrapperValve.invoke (StandardWrapperValve.java:177)
  [13] org.apache.catalina.core.StandardContextValve.invoke (StandardContextValve.java:97)
  [14] org.apache.catalina.authenticator.AuthenticatorBase.invoke (AuthenticatorBase.java:542)
  [15] org.apache.catalina.core.StandardHostValve.invoke (StandardHostValve.java:119)
  [16] org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:92)
  [17] org.apache.catalina.valves.AbstractAccessLogValve.invoke (AbstractAccessLogValve.java:690)
  [18] org.apache.catalina.core.StandardEngineValve.invoke (StandardEngineValve.java:78)
  [19] org.apache.catalina.connector.CoyoteAdapter.service (CoyoteAdapter.java:357)
  [20] org.apache.coyote.http11.Http11Processor.service (Http11Processor.java:400)
  [21] org.apache.coyote.AbstractProcessorLight.process (AbstractProcessorLight.java:65)
  [22] org.apache.coyote.AbstractProtocol$ConnectionHandler.process (AbstractProtocol.java:859)
  [23] org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun (NioEndpoint.java:1,734)
  [24] org.apache.tomcat.util.net.SocketProcessorBase.run (SocketProcessorBase.java:52)
  [25] org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1,191)
  [26] org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:659)
  [27] org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run (TaskThread.java:61)
  [28] java.lang.Thread.run (Thread.java:833)

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