在GWT中使用ApplicationContext

Question

我不想在GWT中使用spring。

我有這樣的一段代碼，我寫道：

public class QuestionServiceImpl extends RemoteServiceServlet 
           implements IQuestionService { 
    private static final long serialVersionUID = 1L; 

    private QuestionDAO questionDAO; 

    @Override 
    public boolean getAllQuestions() { 
     ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml"); 
     questionDAO = (QuestionDAO)context.getBean("questionDAO", QuestionDAO.class); 
     List<Question> questions = questionDAO.getAllQuestions(); 
     System.out.println("questionImpl"); 

     ((ClassPathXmlApplicationContext)context).close(); 
     return true; 
    } 
    /* ... */ 
} 

的問題是，我發現了一個異常：classNotFound。我曾嘗試將mysql-connector-java-5.1.29-bin.jar放在lib中，但沒有成功。

我把lib文件夾放在：gwtrpc-spring-1.0.jar，spring core，beans，context，web。

這是我的異常（以及隨後異常：org.hibernate.HibernateException：通過時引起的「hibernate.dialect」沒有設置訪問DialectResolutionInfo不能爲null）

Cannot load JDBC driver class 'com.mysql.jdbc.Driver' 
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver 
at java.net.URLClassLoader$1.run(Unknown Source) 
at java.net.URLClassLoader$1.run(Unknown Source) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.net.URLClassLoader.findClass(Unknown Source) 
at java.lang.ClassLoader.loadClass(Unknown Source) 
at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:216) 
at java.lang.ClassLoader.loadClass(Unknown Source) 
at org.apache.commons.dbcp2.BasicDataSource.createConnectionFactory(BasicDataSource.java:1992) 
at org.apache.commons.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:1897) 
at org.apache.commons.dbcp2.BasicDataSource$PaGetConnection.run(BasicDataSource.java:2267) 
at org.apache.commons.dbcp2.BasicDataSource$PaGetConnection.run(BasicDataSource.java:2263) 
at java.security.AccessController.doPrivileged(Native Method) 
at org.apache.commons.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1404) 
at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:139) 
at org.hibernate.engine.jdbc.internal.JdbcServicesImpl$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcServicesImpl.java:279) 
at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:124) 
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:89) 
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:206) 
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:178) 
at org.hibernate.cfg.Configuration.buildTypeRegistrations(Configuration.java:1885) 
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1843) 
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1928) 
at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:343) 
at org.springframework.orm.hibernate4.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:431) 
at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:416) 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$6.run(AbstractAutowireCapableBeanFactory.java:1602) 
at java.security.AccessController.doPrivileged(Native Method) 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1599) 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549) 
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539) 
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:681) 
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760) 
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482) 
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139) 
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83) 
at com.appspot.hitquest.server.services.QuestionServiceImpl.getAllQuestions(QuestionServiceImpl.java:21) 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) 
at java.lang.reflect.Method.invoke(Unknown Source) 
at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:115) 
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:561) 
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:265) 
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:305) 
at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) 
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) 
at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74) 
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:127) 
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34) 
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63) 
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) 
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125) 
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366) 
at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349) 
at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116) 
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) 
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) 
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) 
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) 
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) 
at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:98) 
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:491) 
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
at org.mortbay.jetty.Server.handle(Server.java:326) 
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) 
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) 
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) 
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) 
at org.mortbay.jetty.HttpConnection.handמאי 06, 2014 9:27:45 AM org.hibernate.engine.jdbc.internal.JdbcServicesImpl configure 

Answer 1

NoClassDefFoundError的是來自不同ClassNotFoundException通常是因爲第一個CAN意味着該類在兩個jar文件中，而jvm（classloader）不知道選擇哪一個。你可能已經在服務器類路徑中有了mysql jar。

TotalCommander中安裝並使用與「還搜索檔案」搜索一個類名是在驅動程序，但不是像普通的「Driver」 find命令（在com.mysql.jdbc。*）