gradle中使用嵌入式(embedded) tomcat, debug 启动

1.创建一个gradle web项目

buildscript {
repositories {
jcenter()
}

dependencies {
classpath 'com.bmuschko:gradle-tomcat-plugin:2.2.5'
}
}
dependencies {
testCompile group: 'junit', name: 'junit', version: '4.11'

def tomcatVersion = '7.0.59'
tomcat "org.apache.tomcat.embed:tomcat-embed-core:${tomcatVersion}",
"org.apache.tomcat.embed:tomcat-embed-logging-juli:${tomcatVersion}",
"org.apache.tomcat.embed:tomcat-embed-jasper:${tomcatVersion}"
}

apply plugin: 'com.bmuschko.tomcat'

2. 运行

gradlew tomcatRun

Started Tomcat Server
The Server is running at http://localhost:8080/embTomcat[/code] 
端口默认8080，contextPath默认为项目名。

2.1 Task
tomcatRun 为 运行 exploded web application;

tomcatRunWar 则是运行war包。

Task Name
Depends On
Type
Description
tomcatRun
-
TomcatRun
Starts a Tomcat instance and deploys the exploded web application to it.
tomcatRunWar
-
TomcatRunWar
Starts a Tomcat instance and deploys the WAR to it.
tomcatStop
-
TomcatStop
Stops the Tomcat instance.
tomcatJasper
-
TomcatJasper
Runs the JSP compiler and turns JSP pages into Java source usingJasper.
2.2修改默认配置
习惯了'/'作为contextPath:

tomcatRun.contextPath = '/'
tomcatRunWar.contextPath = '/'


这时候运行结果：

:tomcatRunWar
Started Tomcat Server
The Server is running at http://localhost:8080[/code] 
8080端口就挺好的，当然，如果想要自定义也是可以的：

tomcatRun.httpPort=8089


事实上，也提供可更加细腻的自定设置。这时候需要再添加一个依赖：

apply plugin: 'com.bmuschko.tomcat-base'


然后一个自定配置实例：

tomcat {
httpPort = 8090
httpsPort = 8091
enableSSL = true
contextPath = 'sample-app'

users {
user {
username = 'user1'
password = '123456'
roles = ['developers', 'admin']
}

user {
username = 'user2'
password = 'abcdef'
roles = ['manager']
}
}
}


启动运行：

D:\workspace\springboot\embTomcat>gradlew tomcatRun --stacktrace
:compileJava UP-TO-DATE
:processResources UP-TO-DATE
:classes UP-TO-DATE
:tomcatRun
Started Tomcat Server
The Server is running at http://localhost:8090/sample-app[/code] 
可以看到，这个开启了https，页面可以直接访问https的地址了。端口设置为8091. 通过都设置为8443.

2.3 Extension properties
The Tomcat plugin exposes the following properties through the extension named 
tomcat
:

httpPort
: The TCP port which Tomcat should listen for HTTP requests on (defaults to 
8080
).

httpsPort
: The TCP port which Tomcat should listen for HTTPS requests on (defaults to 
8443
).

ajpPort
: The TCP port which Tomcat should listen for AJP requests on (defaults to 
8009
).

stopPort
: The TCP port which Tomcat should listen for admin requests on (defaults to 
8081
).

stopKey
: The key to pass to Tomcat when requesting it to stop (defaults to 
null
).

contextPath
: The URL context path under which the web application will be registered (defaults to WAR name).

enableSSL
: Determines whether the HTTPS connector should be created (defaults to 
false
).

daemon
: Specifies whether the Tomcat server should run in the background. When true, this task completes as soon as the server has started. When false, this task blocks until the Tomcat server is stopped (defaults to 
false
).

keystoreFile
: The keystore file to use for SSL, if enabled (by default, a keystore will be generated).

httpProtocol
: The HTTP protocol handler class name to be used (defaults to 
org.apache.coyote.http11.Http11Protocol
).

httpsProtocol
: The HTTPS protocol handler class name to be used (defaults to
org.apache.coyote.http11.Http11Protocol
).

ajpProtocol
: The AJP protocol handler class name to be used (defaults to 
org.apache.coyote.ajp.AjpProtocol
).

users
: List of users with 
username
, 
password
 and 
roles
. Used to configure tomcat with basic authentication with these users.

到这里基本已经可以使用了。当然，如果想要更多的了解深入的配置：https://github.com/bmuschko/gradle-tomcat-plugin


Task properties
Furthermore, you can set the following optional task properties:

contextPath
: The URL context path your web application will be registered under (defaults to WAR name).

webDefaultXml
: The default web.xml. If it doesn't get defined an instance of
org.apache.catalina.servlets.DefaultServlet
 and 
org.apache.jasper.servlet.JspServlet
 will be set up.

additionalRuntimeResources
: Defines additional runtime JARs or directories that are not provided by the web application.

URIEncoding
: Specifies the character encoding used to decode the URI bytes by the HTTP Connector (defaults to 
UTF-8
).

daemon
: Specifies whether the Tomcat server should run in the background. When true, this task completes as soon as the server has started. When false, this task blocks until the Tomcat server is stopped (defaults to 
false
).

configFile
: The path to the Tomcat context XML file (defaults to 
src/main/webapp/META-INF/context.xml
 for 
tomcatRun
, defaults to 
META-INF/context.xml
 within the WAR for 
tomcatRunWar
).

outputFile
: The file to write Tomcat log messages to. If the file already exists new messages will be appended.

reloadable
: Forces context scanning if you don't use a context file (defaults to 
true
).

keystorePass
: The keystore password to use for SSL, if enabled.

truststoreFile
: The truststore file to use for SSL, if enabled.

truststorePass
: The truststore password to use for SSL, if enabled.

clientAuth
: The clientAuth setting to use, values may be: 
true
, 
false
 or 
want
 (defaults to 
false
).

Note: 
keystoreFile
 and 
truststoreFile
 each require an instance of a 
File
 object e.g. 
file("/path/my.file")


Example
In the following example code, wes declare a custom context file for the task 
tomcatRun
.

tomcatRun.configFile = file('context.xml')


To configure the Jasper compiler task you can choose to set the following properties within the 
jasper
 closure of the
tomcat
 extension:

validateXml
: Determines whether 
web.xml
 should be validated (defaults to 
null
).

validateTld
: Determines whether 
web.xml
 should be validated (defaults to 
null
).

uriroot
: The web application root directory (defaults to 
src/main/webapp
).

webXmlFragment
: The generated web XML fragment file to be referenced by your 
web.xml
 file.

addWebXmlMappings
: Automatically add the generated web XML fragment to the 
web.xml
 file. Caution: this will modify the 
web.xml
 file in the project, not the build directory.

outputDir
: The output directory the compiled JSPs will end up in (defaults to 
build/jasper
).

classdebuginfo
: Should the class file be compiled with debugging information (defaults to 
true
).

compiler
: Which compiler Ant should use to compile JSP pages. See the Ant documentation for more information. If the value is not set, then the default Eclipse JDT Java compiler will be used instead of using Ant. No default value.

compilerSourceVM
: What JDK version are the source files compatible with (defaults to 
1.6
).

compilerTargetVM
: What JDK version are the generated files compatible with (defaults to 
1.6
).

poolingEnabled
: Determines whether tag handler pooling is enabled. This is a compilation option. It will not alter the behaviour of JSPs that have already been compiled (defaults to 
true
).

errorOnUseBeanInvalidClassAttribute
: Should Jasper issue an error when the value of the class attribute in an useBean action is not a valid bean class (defaults to 
true
).

genStringAsCharArray
: Should text strings be generated as char arrays, to improve performance in some cases (defaults to 
false
).

ieClassId
: The class-id value to be sent to Internet Explorer when using 
<jsp:plugin>
 tags (defaults to 
clsid:8AD9C840-044E-11D1-B3E9-00805F499D93
).

javaEncoding
: Java file encoding to use for generating java source files (defaults to 
UTF8
).

trimSpaces
: Should white spaces in template text between actions or directives be trimmed (defaults to 
false
).

xpoweredBy
: Determines whether X-Powered-By response header is added by generated servlet (defaults to 
false
).

Example
tomcat {
jasper {
validateXml = true
webXmlFragment = file("$webAppDir/WEB-INF/generated_web.xml")
outputDir = file("$webAppDir/WEB-INF/src")
}
}




2.4FAQ
编译错误！

org.apache.jasper.JasperException: Unable to compile class for JSP


tomcat7+需要一个jar包来编译，如果没有则添加：

repositories {
flatDir name: 'localRepository', dirs: 'lib'
}


反正我是没遇到。

Why do I get a 
java.lang.ClassCastException
 on 
javax.servlet.Servlet
?

依赖多个版本servlet-api导致了错误：

java.lang.ClassCastException: org.springframework.web.servlet.DispatcherServlet cannot be cast to javax.servlet.Servlet
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1062)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1010)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4935)
at org.apache.catalina.core.StandardContext$3.call(StandardContext.java:5262)
at org.apache.catalina.core.StandardContext$3.call(StandardContext.java:5257)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)


解决：只在编译的时候使用：

providedCompile 'javax.servlet:servlet-api:2.5',
'javax.servlet:jsp-api:2.0'


2.4 Debug
debug启动需要设置gradle的环境变量，即运行gradle命令的时候插入（fork）一些参数命令。

可以设置环境变量GRADLE_OPTS为：

-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=5005


即监听5005端口。这时候运行则会显示：

Listening for transport dt_socket at address: 5005


在idea中监听端口：Run->edit configurations ->+ -> remote, 默认配置就可以了。

什么？不知道怎么设置环境变量？

作为一个java程序员的第一件事就是设置环境变量。当然，我们可以在程序运行的时候添加环境变量，比如在idea中使用自带的gradle插件的时候指定参数，我感觉相当繁琐，不过还是记录下来。

首先，edit configurations  -> + -> gradle ->



然后，点击运行：



这时候就已经在监听5005端口了，只需要添加remote debug就可以了：

edit configurations -> + -> remote:



debug:



2.5 gradle提供debug:
这种方式还是相当繁琐的。不就是设置环境变量吗，好吧，我确实没去研究怎么设置了，应该是在脚本中添加的，以后再研究吧。下面介绍一个简单的方式：

gradlew tomcatRun -Dorg.gradle.debug=true


没错，这样就可以了。剩下的监听remote同上。命令行结束会等待监听，debug remote就可以了。

github: https://github.com/winsnow/jsp-tag

reference：

https://github.com/bmuschko/gradle-tomcat-plugin/blob/master/README.md 
https://docs.gradle.org/current/userguide/gradle_command_line.html   
https://docs.gradle.org/current/userguide/build_environment.html#sec:gradle_properties_and_system_properties