Idea中tomcat启动源码调试进入到tomcat内部进行调试的方法

使用idea开发工具调试代码的时候，如果是java的web项目，使用的是tomcat作为web容器，打断点debug调试跟踪，当跟踪到org.apache.catalina包下的时候，则无法进入，这是因为idea运行的tomcat是通过插件的方式集成的，tomcat里面的lib包不再项目的依赖路径中，所以不能跟踪进去

首先在自己项目中被tomcat回调的接口实现类中，标记一个断点信息，通过idea启动web项目，当出现如图所示的断点信息的时候，因为断点位置标记的是tomcat回调的接口类，所以按照调用堆栈网上则是tomcat内部代码，但此时双击org.apache.catalina包下面的类名，是没有任何反应的，因为我们还没有将tomcat对应的依赖文件添加到classpath下面

添加依赖

<dependency> <groupId>org.apache.tomcat</groupId> <artifactId>tomcat-catalina</artifactId> <version>8.5.55</version> <scope>provided</scope></dependency>

因为运行时使用的是tomcat的lib目录下面的jar文件，所以此处的scope使用provided方式

下面就可以进入到tomcat源码调试了

tomcat启动日志是怎么执行打出来的？

03-Jun-2020 10:31:30.929 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server.服务器版本: Apache Tomcat/8.5.55
03-Jun-2020 10:31:30.938 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 服务器构建:    May 5 2020 22:10:54 UTC
03-Jun-2020 10:31:30.938 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 服务器版本号(:   8.5.55.0
03-Jun-2020 10:31:30.938 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 操作系统名称:   Windows 10
03-Jun-2020 10:31:30.938 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS.版本:      10.0
03-Jun-2020 10:31:30.938 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 架构:       amd64
03-Jun-2020 10:31:30.939 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Java 环境变量:   C:/Program Files/Java/jdk1.8.0_212/jre
03-Jun-2020 10:31:30.939 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Java虚拟机版本:  1.8.0_212-b10
03-Jun-2020 10:31:30.939 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM.供应商:    Oracle Corporation
03-Jun-2020 10:31:30.939 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_BASE:   C:/Users/Administrator/.IntelliJIdea2018.3/system/tomcat/Unnamed_spring-shiro-training
03-Jun-2020 10:31:30.939 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_HOME:   D:/tomcat8.5.55/apache-tomcat-8.5.55

通过定位到 VersionLoggerListener 日志可以查看到

private void log() { log.info(sm.getString("versionLoggerListener.serverInfo.server.version",  ServerInfo.getServerInfo())); log.info(sm.getString("versionLoggerListener.serverInfo.server.built",  ServerInfo.getServerBuilt())); log.info(sm.getString("versionLoggerListener.serverInfo.server.number",  ServerInfo.getServerNumber())); log.info(sm.getString("versionLoggerListener.os.name",  System.getProperty("os.name"))); log.info(sm.getString("versionLoggerListener.os.version",  System.getProperty("os.version"))); log.info(sm.getString("versionLoggerListener.os.arch",  System.getProperty("os.arch"))); log.info(sm.getString("versionLoggerListener.java.home",  System.getProperty("java.home"))); log.info(sm.getString("versionLoggerListener.vm.version",  System.getProperty("java.runtime.version"))); log.info(sm.getString("versionLoggerListener.vm.vendor",  System.getProperty("java.vm.vendor"))); log.info(sm.getString("versionLoggerListener.catalina.base",  System.getProperty("catalina.base"))); log.info(sm.getString("versionLoggerListener.catalina.home",  System.getProperty("catalina.home"))); if (logArgs) { List<String> args = ManagementFactory.getRuntimeMXBean().getInputArguments(); for (String arg : args) {  log.info(sm.getString("versionLoggerListener.arg", arg)); } } if (logEnv) { SortedMap<String, String> sortedMap = new TreeMap<>(System.getenv()); for (Map.Entry<String, String> e : sortedMap.entrySet()) {  log.info(sm.getString("versionLoggerListener.env", e.getKey(), e.getValue())); } } if (logProps) { SortedMap<String, String> sortedMap = new TreeMap<>(); for (Map.Entry<Object, Object> e : System.getProperties().entrySet()) {  sortedMap.put(String.valueOf(e.getKey()), String.valueOf(e.getValue())); } for (Map.Entry<String, String> e : sortedMap.entrySet()) {  log.info(sm.getString("versionLoggerListener.prop", e.getKey(), e.getValue())); } }}

发现是通过键值对的方式获取的，再通过字符串全局搜索发现

但是匹配的是英文，那么中文是怎么打出来的呢？

最后通过调试发现找的是这个

类似上面的东西,调试的时候发现tocmat的东西启动还是相当多的
且看下面这个

idea tomcat启动后的数据

03-Jun-2020 10:31:30.939 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Djava.util.logging.config.file=C:/Users/Administrator/.IntelliJIdea2018.3/system/tomcat/Unnamed_spring-shiro-training/conf/logging.properties
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-agentlib:jdwp=transport=dt_socket,address=127.0.0.1:52290,suspend=y,server=n
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-javaagent:C:/Users/Administrator/.IntelliJIdea2018.3/system/captureAgent/debugger-agent.jar
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dfile.encoding=UTF-8
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dcom.sun.management.jmxremote=
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dcom.sun.management.jmxremote.port=1099
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dcom.sun.management.jmxremote.ssl=false
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dcom.sun.management.jmxremote.password.file=C:/Users/Administrator/.IntelliJIdea2018.3/system/tomcat/Unnamed_spring-shiro-training/jmxremote.password
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dcom.sun.management.jmxremote.access.file=C:/Users/Administrator/.IntelliJIdea2018.3/system/tomcat/Unnamed_spring-shiro-training/jmxremote.access
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Djava.rmi.server.hostname=127.0.0.1
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Djdk.tls.ephemeralDHKeySize=2048
03-Jun-2020 10:31:30.940 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Djava.protocol.handler.pkgs=org.apache.catalina.webresources
03-Jun-2020 10:31:30.941 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dignore.endorsed.dirs=
03-Jun-2020 10:31:30.941 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dcatalina.base=C:/Users/Administrator/.IntelliJIdea2018.3/system/tomcat/Unnamed_spring-shiro-training
03-Jun-2020 10:31:30.941 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Dcatalina.home=D:/tomcat8.5.55/apache-tomcat-8.5.55
03-Jun-2020 10:31:30.941 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：-Djava.io.tmpdir=D:/tomcat8.5.55/apache-tomcat-8.5.55/temp

以上还只是基本的环境配置等启动
然后是准备链接到tomcat服务

03-Jun-2020 10:31:30.941 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent 使用APR版本[1.7.0]加载了基于APR的Apache Tomcat本机库[1.2.24]。
03-Jun-2020 10:31:30.941 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent APR功能：IPv6[true]、sendfile[true]、accept filters[false]、random[true]。
03-Jun-2020 10:31:30.941 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent APR/OpenSSL配置：useAprConnector[false]，useOpenSSL[true]
03-Jun-2020 10:31:30.944 信息 [main] org.apache.catalina.core.AprLifecycleListener.initializeSSL OpenSSL成功初始化 [OpenSSL 1.1.1g  21 Apr 2020]
03-Jun-2020 10:31:31.032 信息 [main] org.apache.coyote.AbstractProtocol.init 初始化协议处理器 ["http-nio-8080"]
03-Jun-2020 10:31:31.046 信息 [main] org.apache.tomcat.util.net.NioSelectorPool.getSharedSelector Using a shared selector for servlet write/read
03-Jun-2020 10:31:31.055 信息 [main] org.apache.catalina.startup.Catalina.load Initialization processed in 175489 ms
03-Jun-2020 10:31:31.080 信息 [main] org.apache.catalina.core.StandardService.startInternal 正在启动服务[Catalina]
03-Jun-2020 10:31:31.080 信息 [main] org.apache.catalina.core.StandardEngine.startInternal Starting Servlet Engine: Apache Tomcat/8.5.55
03-Jun-2020 10:31:31.089 信息 [main] org.apache.coyote.AbstractProtocol.start 开始协议处理句柄["http-nio-8080"]
03-Jun-2020 10:31:31.102 信息 [main] org.apache.catalina.startup.Catalina.start Server startup in 47 ms

tomat启动主要是在Catalina中

然后是

启动

/*** Await and shutdown.*/public void await() { getServer().await();}

其实tomcat启动本质上就是socket的服务器罢了

@Overridepublic void await() { // Negative values - don't wait on port - tomcat is embedded or we just don't like ports if (port == -2) { // undocumented yet - for embedding apps that are around, alive. return; } if (port==-1) { try {  awaitThread = Thread.currentThread();  while(!stopAwait) {  try {   Thread.sleep( 10000 );  } catch( InterruptedException ex ) {   // continue and check the flag  }  } } finally {  awaitThread = null; } return; } // Set up a server socket to wait on try { awaitSocket = new ServerSocket(port, 1,  InetAddress.getByName(address)); } catch (IOException e) { log.error("StandardServer.await: create[" + address    + ":" + port    + "]: ", e); return; } try { awaitThread = Thread.currentThread(); // Loop waiting for a connection and a valid command while (!stopAwait) {  ServerSocket serverSocket = awaitSocket;  if (serverSocket == null) {  break;  }  // Wait for the next connection  Socket socket = null;  StringBuilder command = new StringBuilder();  try {  InputStream stream;  long acceptStartTime = System.currentTimeMillis();  try {   socket = serverSocket.accept(); //一旦accecpt后面就开始执行了   socket.setSoTimeout(10 * 1000); // Ten seconds   stream = socket.getInputStream();  } catch (SocketTimeoutException ste) {   // This should never happen but bug 56684 suggests that   // it does.   log.warn(sm.getString("standardServer.accept.timeout",    Long.valueOf(System.currentTimeMillis() - acceptStartTime)), ste);   continue;  } catch (AccessControlException ace) {   log.warn(sm.getString("standardServer.accept.security"), ace);   continue;  } catch (IOException e) {   if (stopAwait) {   // Wait was aborted with socket.close()   break;   }   log.error(sm.getString("standardServer.accept.error"), e);   break;  }  // Read a set of characters from the socket  int expected = 1024; // Cut off to avoid DoS attack  while (expected < shutdown.length()) {   if (random == null)   random = new Random();   expected += (random.nextInt() % 1024);  }  while (expected > 0) {   int ch = -1;   try {   ch = stream.read();   } catch (IOException e) {   log.warn(sm.getString("standardServer.accept.readError"), e);   ch = -1;   }   // Control character or EOF (-1) terminates loop   if (ch < 32 || ch == 127) {   break;   }   command.append((char) ch);   expected--;  }  } finally {  // Close the socket now that we are done with it  try {   if (socket != null) {   socket.close();   }  } catch (IOException e) {   // Ignore  }  }  // Match against our command string  boolean match = command.toString().equals(shutdown);  if (match) {  log.info(sm.getString("standardServer.shutdownViaPort"));  break;  } else  log.warn(sm.getString("standardServer.invalidShutdownCommand", command.toString())); } } finally { ServerSocket serverSocket = awaitSocket; awaitThread = null; awaitSocket = null; // Close the server socket and return if (serverSocket != null) {  try {  serverSocket.close();  } catch (IOException e) {  // Ignore  } } }}

tomcat容器启动之后，下面就是Springmvc模块的内容了