为Spring Boot应用程序生成war软件包时，maven构建失败? [英] maven build failing when generating war package for spring boot application?

问题描述

这是我以前的问题的扩展

This is an extension to my previous question here at SO. As per this post, main method is NOT required to generate a deployable war

我正在尝试为上传文件.可以在此处.

I am trying to generate a deployable war for this simple application of uploading files. The source code can be for this example application can be found here.

按照从spring boot到jar到war转换的说明，我更改了pom.xml以反映以下内容. (只需将tomcat依赖项添加到范围provided).

Following the instructions from spring boot for jar to war conversion, I changed my pom.xml to reflect the following. (Just added tomcat dependency with scope provided).

参考: http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#build-tool-plugins-maven-packaging

      <?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.springframework</groupId>
    <artifactId>gs-uploading-files</artifactId>
    <version>0.1.0</version>
    <packaging>war</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.3.RELEASE</version>
    </parent>


    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>

    </dependencies>

    <properties>
        <java.version>1.7</java.version>
    </properties>

    <repositories>
        <repository>
            <id>spring-releases</id>
            <name>Spring Releases</name>
            <url>https://repo.spring.io/libs-release</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-releases</id>
            <name>Spring Releases</name>
            <url>https://repo.spring.io/libs-release</url>
        </pluginRepository>
    </pluginRepositories>
</project>

然后我按如下所示更改了Application.java

Then I changed Application.java as follows

参考:我尝试了两种情况.都失败，并显示以下错误(Unable to find main class).

I tried two scenarios. both fail with the following error (Unable to find main class).

1. 没有主要方法(注意，我已经在上面注释了主要方法)
2. 没有application.Java文件(注释了该文件中的所有内容-这里未显示)

错误:

[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 9.218s
[INFO] Finished at: Thu Apr 23 11:46:24 PDT 2015
[INFO] Final Memory: 22M/222M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:1.2.3.RELEASE:repackage (default) on project gs-uploading-files: Execution default of goal org.springframework.boot:spring-boot-maven-plugin:1.2.3.RELEASE:repackage failed: Unable to find main class -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionException

PS:当我的主要方法完好无损时，构建成功

推荐答案

如果您想同时获得两者的好处-即与嵌入式Tomcat 和正常运行的独立可执行文件之战可以在外部Tomcat中部署战争-您需要有一个带有main方法的类.所以，

If you want to get both the benefits - i.e. standalone executable war with embedded Tomcat and the normal war deployable in external Tomcat - you need to have a class with main method. So,

• 在Application.java中启用main()方法.
• 配置spring-boot-maven-plugin以便与主类一起指定该类(如果您有主类，Spring应该无论如何都应找到它，但是我想明确地说是很好的): <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <version>${spring-boot-version}</version> <configuration> <mainClass>the.package.of.Application</mainClass> </configuration> <executions> <execution> <goals> <goal>repackage</goal> </goals> </execution> </executions> </plugin>
• 使用provided范围删除pom中的spring-boot-starter-tomcat依赖项. Spring Boot神奇地知道如何启用/禁用嵌入式Tomcat.

• Enable the main() method in your Application.java.
• Configure spring-boot-maven-plugin to specify the class with the main class (Spring should find it anyway if you have one, but good to be explicit I guess): <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <version>${spring-boot-version}</version> <configuration> <mainClass>the.package.of.Application</mainClass> </configuration> <executions> <execution> <goals> <goal>repackage</goal> </goals> </execution> </executions> </plugin>
• Remove spring-boot-starter-tomcat dependency in your pom with provided scope. Spring boot magically knows how to enable/disable embedded Tomcat.

通过此操作，您应该能够通过将Application.java类作为普通Java应用程序运行，从IDE中启动Spring应用程序，构建一个既可以独立执行又可以像往常一样在外部Tomcat中部署的war文件.

With this you should be able to launch your Spring app from IDE by just running the Application.java class as a normal Java app, build a war file that is both standalone executable and deployable in external Tomcat as usual too.

我目前正在使用Spring Boot 1.0.1.RELEASE通过这种设置来构建REST API，并且在所有三种模式下均能很好地工作.

I am currently building REST APIs with Spring Boot 1.0.1.RELEASE with this kind of setup and it works great in all three modes.

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