无法启动Spring-Boot示例

Question

I was trying out spring-boot samples. This is specifically the example spring-boot-sample-tomcat , that I have been trying to run.

As instructed, I have run mvn package and it is successful. But when running the jar java -jar target/spring-boot-sample-tomcat-0.5.0.BUILD-SNAPSHOT.jar , I am getting the below exception.

Please confirm if there is any jars which need to be put in the classpath. Or what to do to make it run.

Link to the pom.xml which is being used.

Exception in thread "main" java.lang.NoClassDefFoundError: javax/servlet/ServletContextListener
        at java.lang.Class.getDeclaredMethods0(Native Method)
        at java.lang.Class.privateGetDeclaredMethods(Class.java:2427)
        at java.lang.Class.getDeclaredMethod(Class.java:1935)
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
        at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.ClassNotFoundException: javax.servlet.ServletContextListener
        at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at org.springframework.boot.loader.LaunchedURLClassLoader.findClass(LaunchedURLClassLoader.java:110)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at org.springframework.boot.loader.LaunchedURLClassLoader.doLoadClass(LaunchedURLClassLoader.java:93)
        at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:65)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
        ... 5 more

Answer 1

You might try adding this segment to your pom:

<properties>
  <start-class>org.springframework.boot.sample.tomcat.SampleTomcatApplication</start-class>
</properties>

This defines the "main" to use explicitly. Spring boot is supposed to pick up the main automatically, but being explicit is a good way to go. That was the only way I was able to get another project I was working on to work using the "java -jar" invocation working.

Answer 2

I just executed:

$ git fetch upstream
$ git merge upstream/master
Already up-to-date.
$ cd spring-boot-samples/spring-boot-sample-tomcat/
$ mvn clean package && java -jar target/spring-boot-sample-tomcat-0.5.0.BUILD-SNAPSHOT.jar
...
Results :

Tests run: 2, Failures: 0, Errors: 0, Skipped: 0
...
2013-09-23 08:52:33.713  INFO 698 --- [           main] o.s.b.s.tomcat.SampleTomcatApplication   : Starting SampleTomcatApplication on retina with PID 698 (/Users/gturnquist/src/spring-boot/spring-boot-samples/spring-boot-sample-tomcat/target/spring-boot-sample-tomcat-0.5.0.BUILD-SNAPSHOT.jar started by gturnquist)
2013-09-23 08:52:33.753  INFO 698 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@21301fa: startup date [Mon Sep 23 08:52:33 CDT 2013]; root of context hierarchy
2013-09-23 08:52:34.673  INFO 698 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2013-09-23 08:52:34.674  INFO 698 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/7.0.42
2013-09-23 08:52:34.753  INFO 698 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2013-09-23 08:52:34.754  INFO 698 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1004 ms
2013-09-23 08:52:34.902  INFO 698 --- [ost-startStop-1] o.s.b.s.tomcat.SampleTomcatApplication   : ServletContext initialized
2013-09-23 08:52:34.918  INFO 698 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2013-09-23 08:52:34.919  INFO 698 --- [ost-startStop-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2013-09-23 08:52:34.991  INFO 698 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2013-09-23 08:52:35.127  INFO 698 --- [ost-startStop-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/],methods=[],params=[],headers=[],consumes=[],produces=[],custom=[]}" onto public java.lang.String org.springframework.boot.sample.tomcat.web.SampleController.helloWorld()
2013-09-23 08:52:35.169  INFO 698 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2013-09-23 08:52:35.169  INFO 698 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2013-09-23 08:52:35.377  INFO 698 --- [ost-startStop-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 458 ms
2013-09-23 08:52:37.548  INFO 698 --- [           main] o.s.b.s.tomcat.SampleTomcatApplication   : Started SampleTomcatApplication in 4.299 seconds

Perhaps you need to update your clone and rebuild?

Answer 3

I had the same issue and my problem was that I had the wrong class configured on start-class under properties, once I removed it, everything was fine:

<properties>
  <start-class>wrong class here</start-class>  <-- REMOVE THIS LINE
</properties>