java - 动态方法中的 InvokingTargetException

Question

我这里遇到了奇怪的情况..

首先我从我的 bean 中获取这个方法:

#{segurancaBean.callSubAcaoMethod(subAcao, moduloBean.class.name, modulo.id)}

在我的后台:

public void callSubAcaoMethod(Acao acao, String bean, Long id){
try {
    Class<?> clazz = Class.forName(bean);
    Method method = clazz.getMethod(acao.getTipoAcao().getNmBean(), Long.class);
    Object obj = clazz.newInstance();
    Object ins = new Object();
    ins = method.invoke(obj, id);

} catch (ClassNotFoundException | SecurityException | IllegalArgumentException | InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException ex) {
    Logger.getLogger(SegurancaBean.class.getName()).log(Level.SEVERE, null, ex);
}
}

因此，我传递了方法名称 (subAcao)、bean 类和 ID

这里我得到了我的方法:

@Override
public void btnAlterar(Long id){
Modulo m = new Modulo();
m = moduloServico.pesquisar(id);

}

如果我只打印一条消息，它就可以工作，但是如果我尝试使用 DAO 来查找对象，我会在这一行中得到 IncationTargetException:

ins = method.invoke(obj, id);

抱歉英语不好

详细来说，我在 View 中添加了一个直接调用该方法的按钮(没有动态)。效果很好。 :/

这是完整的堆栈跟踪

Grave:   java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at br.com.ms.syscon.seguranca.bean.SegurancaBean.callSubAcaoMethod(SegurancaBean.java:184)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at javax.el.ELUtil.invokeMethod(ELUtil.java:332)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:537)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:256)
at com.sun.el.parser.AstValue.invoke(AstValue.java:283)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40)
at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:147)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:813)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIData.broadcast(UIData.java:1108)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:344)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
at org.primefaces.rio.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:34)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
at br.com.ms.syscon.seguranca.filtro.SegurancaFiltro.doFilter(SegurancaFiltro.java:72)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:316)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:415)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:282)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:201)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:175)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:561)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at br.com.ms.syscon.seguranca.bean.ModuloBean.btnAlterar(ModuloBean.java:44)
... 64 more

Answer 1

由于您使用 Class.newInstance() 实例化该类，因此不会发生任何注释的 CDI 处理(也不会发生范围和生命周期管理)。因此，您期望注入(inject)的任何内容都不会被注入(inject)，而是保持初始化为 null。

参见https://stackoverflow.com/a/24852542/1172714 .