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

在gradle項目中使用embedded tomcat。

最開始部署項目需要手動將web項目打成war包，然后手動上傳到tomcat的webapp下，然后啟動tomcat來部署項目。這種手動工作通常還要指定端口，指定項目位置等，這些操作是重復的操作。

開發的時候，ide自然想到集成這些功能，於是都是server模塊，設置好參數就可以run server，測試了。個人操作的時候確實挺方便的，然而當團隊協作的時候，每個人都要手動去設置這些參數，而且大家或許還在使用着各種各樣的idea。eclipse和idea的配置方式截然不同。這好在都是java程序員，但還有前端呢，前端的同事一起開發的時候，他們會感覺這些配置繁瑣。

后來發現，框架發展到現在反而更傾向於命令行的方式了。embedded 就是一種流行的方式。

 

當項目集成了embedded tomcat之后，只要type gradlew tomcatRun就可以運行項目。這樣即使是前端程序員也可以本地調試項目了。

 

• 創建一個gradle web項目
• 運行
• task
• 修改默認配置
• 一些配置屬性
• FAQ
• debug
• gradle 提供的 debug

1.創建一個gradle web項目

在idea中，new -> project -> gradle -> web 就可以創建一個空的gradle web項目。

在build.gradle 中添加tomcat的依賴:

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}"
}

 

添加tomcat 插件：

apply plugin: 'com.bmuschko.tomcat'

 

2. 運行

這時候就可以運行了。在命令行中輸入：

gradlew tomcatRun

第一次運行會下載對應的jar包，然后顯示：

Started Tomcat Server                                          
The Server is running at http://localhost:8080/embTomcat

端口默認8080，contextPath默認為項目名。

 

2.1 Task

tomcatRun 為 運行 exploded web application;

tomcatRunWar 則是運行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修改默認配置

習慣了'/'作為contextPath:

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

這時候運行結果：

:tomcatRunWar                 
Started Tomcat Server
The Server is running at http://localhost:8080

 

8080端口就挺好的，當然，如果想要自定義也是可以的：

tomcatRun.httpPort=8089

 

事實上，也提供可更加細膩的自定設置。這時候需要再添加一個依賴：

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

然后一個自定配置實例：

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']
        }
    }
}

啟動運行：

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

可以看到，這個開啟了https，頁面可以直接訪問https的地址了。端口設置為8091. 通過都設置為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 toorg.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.

到這里基本已經可以使用了。當然，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 oforg.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 thetomcat 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

編譯錯誤！

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

tomcat7+需要一個jar包來編譯，如果沒有則添加：

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

反正我是沒遇到。

 

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

依賴多個版本servlet-api導致了錯誤：

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)

解決：只在編譯的時候使用：

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

 

2.4 Debug

debug啟動需要設置gradle的環境變量，即運行gradle命令的時候插入（fork）一些參數命令。

可以設置環境變量GRADLE_OPTS為：

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

即監聽5005端口。這時候運行則會顯示：

Listening for transport dt_socket at address: 5005

在idea中監聽端口：Run->edit configurations ->+ -> remote, 默認配置就可以了。

 

什么？不知道怎么設置環境變量？

作為一個java程序員的第一件事就是設置環境變量。當然，我們可以在程序運行的時候添加環境變量，比如在idea中使用自帶的gradle插件的時候指定參數，我感覺相當繁瑣，不過還是記錄下來。

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

 

然后，點擊運行：

 

這時候就已經在監聽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:

這種方式還是相當繁瑣的。不就是設置環境變量嗎，好吧，我確實沒去研究怎么設置了，應該是在腳本中添加的，以后再研究吧。下面介紹一個簡單的方式：

gradlew tomcatRun -Dorg.gradle.debug=true

沒錯，這樣就可以了。剩下的監聽remote同上。命令行結束會等待監聽，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