我有一个带有Maven的Spring应用程序，我想将其部署在Google App Engine上。我已经在AppEngine Console中渴望一个Cloud SQL MySQLInstance。该应用程序在我的本地主机上运行良好，但在将其部署到 GAE 后，它得到这个 NoClassDefFoundError：无法初始化类 com.mysql.jdbc.Driver
12:54:39.191
Failed startup of context com.google.apphosting.utils.jetty.RuntimeAppEngineWebAppContext@1819bb7{/,/base/data/home/apps/s~gps-trackman/1.383642890894410495}
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'MyDataSource' defined in class path resource [com/pekam/AppConfig.class]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public javax.sql.DataSource com.pekam.AppConfig.MyDataSource()] threw exception; nested exception is java.lang.NoClassDefFoundError: Could not initialize class com.mysql.jdbc.Driver
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:597)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1094)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:989)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:703)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:648)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:311)
at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:130)
at org.springframework.boot.legacy.context.web.SpringBootContextLoaderListener.initWebApplicationContext(SpringBootContextLoaderListener.java:61)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
at org.mortbay.jetty.handler.ContextHandler.startContext(ContextHandler.java:548)
at org.mortbay.jetty.servlet.Context.startContext(Context.java:136)
at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)
at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.createHandler(AppVersionHandlerMap.java:199)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.getHandler(AppVersionHandlerMap.java:174)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:134)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:527)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:437)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:444)
at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:220)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:308)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:300)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:441)
at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public javax.sql.DataSource com.pekam.AppConfig.MyDataSource()] threw exception; nested exception is java.lang.NoClassDefFoundError: Could not initialize class com.mysql.jdbc.Driver
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:188)
at org.springframework.beans.factory.support.ConstructorResolver$3.run(ConstructorResolver.java:580)
at java.security.AccessController.doPrivileged(Native Method)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:577)
... 34 more
Caused by: java.lang.NoClassDefFoundError: Could not initialize class com.mysql.jdbc.Driver
at com.google.appengine.runtime.Request.process-a80cdeb0ea590f84(Request.java)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:147)
at org.springframework.jdbc.datasource.DriverManagerDataSource.setDriverClassName(DriverManagerDataSource.java:127)
at com.pekam.AppConfig.MyDataSource(AppConfig.java:57)
at com.pekam.AppConfig$$EnhancerBySpringCGLIB$$3987b163.CGLIB$MyDataSource$2(<generated>)
at com.pekam.AppConfig$$EnhancerBySpringCGLIB$$3987b163$$FastClassBySpringCGLIB$$828632e0.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:312)
at com.pekam.AppConfig$$EnhancerBySpringCGLIB$$3987b163.MyDataSource(<generated>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:45)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:166)
at org.springframework.beans.factory.support.ConstructorResolver$3.run(ConstructorResolver.java:580)
at java.security.AccessController.doPrivileged(Native Method)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:577)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1094)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:989)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:703)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:648)
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要使用 GAE 的 jdbc 驱动程序;您可以使用类似于以下内容的代码片段：Class.forName（"com.mysql.jdbc.GoogleDriver"）;URL = "JDBC：Google：MySQL：//...
并且还可以通过将"use-google-connector-j"属性设置为 true 来更改"AppEngine-Web.xml"。
有关更多详细信息，请参阅以下链接：https://cloud.google.com/appengine/docs/java/cloud-sql/#Java_Connect_to_your_database
您必须下载mysql-connector-java.jar并将其添加到类路径中。