Maven项目在eclipse中抛出ClassNotFoundException

Question

在eclipse中运行带有maven依赖项的spring boot应用程序时，我在启动时遇到以下异常：

java.lang.NoClassDefFoundError: org/springframework/web/context/support/GenericWebApplicationContext
at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_92]
at java.lang.ClassLoader.defineClass(Unknown Source) ~[na:1.8.0_92]
at java.security.SecureClassLoader.defineClass(Unknown Source) ~[na:1.8.0_92]
at java.net.URLClassLoader.defineClass(Unknown Source) ~[na:1.8.0_92]
at java.net.URLClassLoader.access$100(Unknown Source) ~[na:1.8.0_92]
at java.net.URLClassLoader$1.run(Unknown Source) ~[na:1.8.0_92]
at java.net.URLClassLoader$1.run(Unknown Source) ~[na:1.8.0_92]
at java.security.AccessController.doPrivileged(Native Method) ~[na:1.8.0_92]
at java.net.URLClassLoader.findClass(Unknown Source) ~[na:1.8.0_92]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_92]
at java.lang.ClassLoader.defineClass(Unknown Source) ~[na:1.8.0_92]
at java.security.SecureClassLoader.defineClass(Unknown Source) ~[na:1.8.0_92]
at java.net.URLClassLoader.defineClass(Unknown Source) ~[na:1.8.0_92]
at java.net.URLClassLoader.access$100(Unknown Source) ~[na:1.8.0_92]
at java.net.URLClassLoader$1.run(Unknown Source) ~[na:1.8.0_92]
at java.net.URLClassLoader$1.run(Unknown Source) ~[na:1.8.0_92]
at java.security.AccessController.doPrivileged(Native Method) ~[na:1.8.0_92]
at java.net.URLClassLoader.findClass(Unknown Source) ~[na:1.8.0_92]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
at java.lang.Class.forName0(Native Method) ~[na:1.8.0_92]
at java.lang.Class.forName(Unknown Source) ~[na:1.8.0_92]
at org.springframework.boot.SpringApplication.createApplicationContext(SpringApplication.java:574) ~[spring-boot-1.3.0.RELEASE.jar:1.3.0.RELEASE]
at org.springframework.boot.SpringApplication.doRun(SpringApplication.java:325) ~[spring-boot-1.3.0.RELEASE.jar:1.3.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:295) ~[spring-boot-1.3.0.RELEASE.jar:1.3.0.RELEASE]
at co.hafiz.cm.launcher.Launcher.lambda$0(Launcher.java:33) [classes/:na]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[na:1.8.0_92]
at java.lang.Thread.run(Unknown Source) ~[na:1.8.0_92]
Caused by: java.lang.ClassNotFoundException: org.springframework.web.context.support.GenericWebApplicationContext
at java.net.URLClassLoader.findClass(Unknown Source) ~[na:1.8.0_92]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_92]
... 32 common frames omitted

在Eclipse中的maven依赖项中，我得到了：

正如您所见，spring-web可用，其中包含 org.springframework.web.context.support.GenericWebApplicationContext 会有什么问题？

Answer 1

在我的Spring Boot项目中添加依赖spring-boot-starter-web解决了同样的错误。此外，您似乎在Spring Boot方面有很多不必要的依赖项。在Spring框架的情况下可能需要一些，但在Spring Boot中则不需要。

Answer 2

您缺少spring框架，将其添加到您的依赖项

<!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>4.3.5.RELEASE</version>
</dependency>