我正在尝试连接到远程 MySQL 服务器。我已成功从 Eclipse(数据源 View )建立连接，现在可以浏览数据库的内容。
但现在我希望能够在我的 Java EE 6 应用程序中使用该数据库，但它不起作用。我尝试过的:
在管理面板中添加了用户名、密码、服务器名称、URL、端口作为属性。
这是我使用的 URL:jdbc:mysql://MYHOST:3306/MYDATABASE 可能没有任何问题。我还将我的 IP 添加到了 CPanel 中的远程列表中，以便我可以远程连接。我已经下载了这个驱动程序:http://www.java.net/external?url=http://dev.mysql.com/downloads/connector/j/并将其添加到domains/domain1/lib文件夹中。
我还看到另外 4 个文件夹；数据库、ext、applibs 和类，因此我将驱动程序添加到这些文件夹中以确保确定。这是错误的吗？我是否需要将驱动程序添加到 Eclipse 项目中的某个文件夹中才能使其正常工作？
资源类型:javax.sql.DataSource 数据源类名:com.mysql.jdbc.jdbc2.可选.MysqlConnectionPoolDataSource
更新
HTTP Status 500 -
type Exception report
message
descriptionThe server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: WELD-000049 Unable to invoke [method] @PostConstruct public no.breakpoint.sertifikat.interfaces.QuestionController.intialize() on no.breakpoint.sertifikat.interfaces.QuestionController@10614f3d
root cause
org.jboss.weld.exceptions.WeldException: WELD-000049 Unable to invoke [method] @PostConstruct public no.breakpoint.sertifikat.interfaces.QuestionController.intialize() on no.breakpoint.sertifikat.interfaces.QuestionController@10614f3d
root cause
java.lang.reflect.InvocationTargetException
root cause
javax.ejb.EJBException
root cause
java.lang.NullPointerException
note The full stack traces of the exception and its root causes are available in the GlassFish Server Open Source Edition 3.1.1 logs. GlassFish Server Open Source Edition 3.1.1
EJB:
@Override
public List<Question> all() {
// List<Question> list = new ArrayList<Question>();
// Question question = new Question();
// question.setDescription("SDfasfasdfasf");
// question.setId(32);
// question.setImage("sdafasdf");
// list.add(question);
//
// return list;
//
return questionDao.all();
}
JSF bean
@Named
@RequestScoped
public class QuestionController {
@EJB
private QuestionLocalBusiness questionManager;
private List<Question> questions;
@PostConstruct
public void intialize() {
questions = questionManager.all();
}
public void setQuestions(List<Question> list) {
questions = list;
}
public List<Question> getQuestions() {
return questions;
}
}
错误日志:
WARNING: StandardWrapperValve[FacesServlet]: PWC1406: Servlet.service() for servlet FacesServlet threw exception
org.jboss.weld.exceptions.WeldException: WELD-000049 Unable to invoke [method] @PostConstruct public com.bpoint.interfaces.QuestionController.intialize() on com.bpoint.interfaces.QuestionController@10614f3d
at org.jboss.weld.bean.AbstractClassBean.defaultPostConstruct(AbstractClassBean.java:595)
at org.jboss.weld.bean.ManagedBean$ManagedBeanInjectionTarget.postConstruct(ManagedBean.java:200)
at org.jboss.weld.bean.ManagedBean.create(ManagedBean.java:340)
at org.jboss.weld.context.AbstractContext.get(AbstractContext.java:121)
at org.jboss.weld.bean.proxy.ContextBeanInstance.getInstance(ContextBeanInstance.java:99)
at org.jboss.weld.bean.proxy.ProxyMethodHandler.invoke(ProxyMethodHandler.java:87)
at no.breakpoint.sertifikat.interfaces.org$jboss$weld$bean-SertifikatWeb_war-ManagedBean-class_no$breakpoint$sertifikat$interfaces$QuestionController_$$_WeldClientProxy.getQuestions(org$jboss$weld$bean-SertifikatWeb_war-ManagedBean-class_no$breakpoint$sertifikat$interfaces$QuestionController_$$_WeldClientProxy.java)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:302)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at com.sun.el.parser.AstValue.getValue(AstValue.java:116)
at com.sun.el.parser.AstValue.getValue(AstValue.java:163)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:219)
at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:55)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UIData.getValue(UIData.java:731)
at javax.faces.component.UIData.getDataModel(UIData.java:1798)
at javax.faces.component.UIData.getRowCount(UIData.java:356)
at org.primefaces.component.datatable.DataTableRenderer.encodeTbody(DataTableRenderer.java:456)
at org.primefaces.component.datatable.DataTableRenderer.encodeRegularTable(DataTableRenderer.java:201)
at org.primefaces.component.datatable.DataTableRenderer.encodeMarkup(DataTableRenderer.java:180)
at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:85)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1763)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1756)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:401)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:288)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.weld.util.reflection.SecureReflections$13.work(SecureReflections.java:305)
at org.jboss.weld.util.reflection.SecureReflectionAccess.run(SecureReflectionAccess.java:54)
at org.jboss.weld.util.reflection.SecureReflectionAccess.runAsInvocation(SecureReflectionAccess.java:163)
at org.jboss.weld.util.reflection.SecureReflections.invoke(SecureReflections.java:299)
at org.jboss.weld.introspector.jlr.WeldMethodImpl.invoke(WeldMethodImpl.java:193)
at org.jboss.weld.bean.AbstractClassBean.defaultPostConstruct(AbstractClassBean.java:591)
... 66 more
Caused by: javax.ejb.EJBException
at com.sun.ejb.containers.BaseContainer.processSystemException(BaseContainer.java:5193)
at com.sun.ejb.containers.BaseContainer.completeNewTx(BaseContainer.java:5091)
at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4879)
at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:2039)
at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1990)
at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:222)
at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:88)
at $Proxy231.all(Unknown Source)
at no.breakpoint.sertifikat.interfaces.QuestionController.intialize(QuestionController.java:24)
... 76 more
Caused by: java.lang.NullPointerException
at no.breakpoint.sertifikat.application.QuestionManagerEJB.all(QuestionManagerEJB.java:52)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1052)
at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1124)
at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5366)
at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:619)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:571)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:162)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:144)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:861)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:370)
at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5338)
at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5326)
at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:214)
... 79 more
DAO:
package no.breakpoint.sertifikat.infrastructure;
import java.util.List;
@NamedQuery(name = "allQuestions", query = "SELECT q FROM Question q")
public class DefaultQuestionDao implements QuestionDao {
@PersistenceContext(unitName = "MyDatabasePU")
private EntityManager entityManager;
@Override
public void create(Question question) {
entityManager.persist(question);
}
@Override
public void delete(Question question) {
entityManager.remove(question);
}
@Override
public void update(Question question) {
entityManager.merge(question);
}
@Override
public Question read(Integer id) {
return entityManager.find(Question.class, id);
}
@Override
public List<Question> all() {
TypedQuery<Question> query = entityManager.createNamedQuery("allQuestions", Question.class);
return query.getResultList();
}
}
如果我取消注释我现在注释的内容，我使用的 dataTable 就会起作用，并且 500 错误就会消失。但是当我尝试从数据库中获取它时，它给了我。
最佳答案
Caused by: java.lang.NullPointerException at no.breakpoint.sertifikat.application.QuestionManagerEJB.all(QuestionManagerEJB.java:52)
所以，EntityManager是null吗？ @PersistenceContext只会注入(inject)到容器/框架托管类中，例如 @Stateless EJB，CDI @Named bean，一个 JSF @ManagedBean bean 等。但是，您的 DefaultQuestionDao 似乎根本不受管理。
鉴于到目前为止的设置，我将开始将您的 DefaultQuestionDao 标记为 @Stateless EJB。整个设置充其量是令人困惑的，堆栈跟踪告诉我在代码片段中没有看到的 QuestionManagerEJB ，只有一个 DefaultQuestionDao 和一个 QuestionBusinessLocal。也许您还需要将 DefaultQuestionDao 作为 @EJB 注入(inject) QuestionManagerEJB 中。
此外，还有另一个问题:@NamedQuery必须在 @Entity 上进行注释类或其父类(super class)之一，否则将找不到。
关于java - 如何从 Glassfish 连接到外部 MySQL 服务器，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/7794862/