tomcat 类路径上有多个servlet-api库时出错

guz6ccqo  于 2022-11-13  发布在  其他
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我有嵌入式Tomcat运行的Sping Boot 应用程序。我在Docker容器中运行它。当我尝试在容器中遵循关于Spring Boot的page并构建分层映像时,我在尝试启动容器时收到了下面提到的错误。我知道最好的方法是从我的依赖项中排除旧版本的servlet-api,但这是不可能的,因为在我这样做时,此依赖项停止工作。不幸的是,我也无法摆脱这种依赖。有没有办法强制Sping Boot 使用类路径中的特定实现?我已经尝试过Jetty和Undertow,并成功启动了docker,但使用旧版本的lib无法正常工作。
另一个问题是,当我只是复制jar并启动它时,为什么它还能工作?
我尝试构建的Dockerfile:

FROM adoptopenjdk:11-jre-hotspot

ARG DEPENDENCY=target/dep 
COPY ${DEPENDENCY}/BOOT-INF/lib /app/lib 
COPY ${DEPENDENCY}/META-INF /app/META-INF
COPY ${DEPENDENCY}/BOOT-INF/classes /app
ENTRYPOINT ["java","-cp","app:app/lib/*","com.test.App"]

工作的停靠文件:

FROM adoptopenjdk:11-jre-hotspot

COPY /target/application.jar /app/application.jar
COPY /target/lib /app/lib

ENTRYPOINT ["java", "-jar", "app/application.jar"]

工作的方法需要pom.xml中的附加插件才能实现:

<plugin>
                        <groupId>org.springframework.boot</groupId>
                        <artifactId>spring-boot-maven-plugin</artifactId>
                        <executions>
                            <execution>
                                <id>build-info</id>
                                <goals>
                                    <goal>build-info</goal>
                                </goals>
                            </execution>
                        </executions>
                    </plugin>
                    <plugin>
                        <groupId>org.apache.maven.plugins</groupId>
                        <artifactId>maven-jar-plugin</artifactId>
                        <version>3.1.0</version>
                        <configuration>
                            <finalName>ttom-osm-converter</finalName>
                            <archive>
                                <manifest>
                                    <addClasspath>true</addClasspath>
                                    <classpathPrefix>lib/</classpathPrefix>
                                    <mainClass>com.tomtom.mep.App</mainClass>
                                </manifest>
                            </archive>
                        </configuration>
                    </plugin>
                    <plugin>
                        <groupId>org.apache.maven.plugins</groupId>
                        <artifactId>maven-dependency-plugin</artifactId>
                        <executions>
                            <execution>
                                <id>copy-dependencies</id>
                                <phase>prepare-package</phase>
                                <goals>
                                    <goal>copy-dependencies</goal>
                                </goals>
                                <configuration>
                                    <outputDirectory>${project.build.directory}/lib</outputDirectory>
                                </configuration>
                            </execution>
                        </executions>
                    </plugin>

来自POM的相关性:

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>io.micrometer</groupId>
        <artifactId>micrometer-registry-prometheus</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-configuration-processor</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-aop</artifactId>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>
    <dependency>  <!-- lib contains servlet-api-2.5 -->
        <groupId>com.test.lib</groupId> 
        <artifactId>client</artifactId>
        <version>${model.client.version}</version>
    </dependency>

错误:

java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [NonLoginAuthenticator[StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[/path]

***************************
APPLICATION FAILED TO START
***************************

Description:

An attempt was made to call a method that does not exist. The attempt was made from the following location:

org.apache.catalina.authenticator.AuthenticatorBase.startInternal(AuthenticatorBase.java:1220)

The following method did not exist:

'java.lang.String javax.servlet.ServletContext.getVirtualServerName()'

The method's class, javax.servlet.ServletContext, is available from the following locations:

jar:file:/app/lib/servlet-api-2.5.jar!/javax/servlet/ServletContext.class
jar:file:/app/lib/javax.servlet-api-4.0.1.jar!/javax/servlet/ServletContext.class
jar:file:/app/lib/tomcat-embed-core-9.0.29.jar!/javax/servlet/ServletContext.class

  It was loaded from the following location:

file:/app/lib/servlet-api-2.5.jar

Action:

Correct the classpath of your application so that it contains a single, compatible version of javax.servlet.ServletContext
a8jjtwal

a8jjtwal1#

从关于'javax.servlet.servletContext.getVirtualServerName().的错误中,我们可以看到它是在Servlet 3.1中添加的:您应该排除servlet-api:2.5。
请使用以下命令:

mvn dependency:tree -Dincludes='*:servlet-api'

这将列出所有模块/依赖项,包括servlet-api
然后从依赖项中排除错误版本:com.test.lib客户端甚至不应该将其包括在第一位置,这意味着还应该在其中提供依赖性。

<dependency>  <!-- lib contains servlet-api-2.5 -->
  <groupId>com.test.lib</groupId> 
  <artifactId>client</artifactId>
  <version>${model.client.version}</version>
  <exclusions> <exclusion> <groupId>...</groupId> <artifactId>servlet-api</artifactId> </exclusion> </exclusions>
</dependency>

请注意,servlet-api groupId会随着时间的推移而更改:这可能是Maven不选择“好的”servlet-api的一个原因。
我建议你使用maven-enforcer-plugin来锁定这些坏的依赖项:

<rules>
            <bannedDependencies>
              <excludes>
                <exclude>*:servlet-api:2.5</exclude>
              </excludes>
            </bannedDependencies>
          </rules>
          <fail>true</fail>

如需详细信息,请参阅http://maven.apache.org/enforcer/enforcer-rules/bannedDependencies.html
现在,您提到您的lib(com.test.lib)在没有servlet-api 2.5的情况下似乎无法工作,这意味着它使用的代码可能在Servlet 2.5和3.1之间被删除:您唯一行动是升级您的库,使其不依赖于上述代码:

  • 加载第一个servlet-api(2.5)
  • Tomcat和Sping Boot 是根据较新版本编译的
  • Tomcat/Sping Boot 可能会尝试使用以后版本中添加的方法
  • 您将遇到另一个错误,依此类推。
zd287kbt

zd287kbt2#

您可以访问路径:

~/.m2/repository/javax/servlet/servlet-api

并清除文件夹serverlet。例如:

rm -rf 2.5

最后,您重新运行应用程序,一切正常。

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