Java 速度-空点异常

在我的搜索过程中，我想对我的问题提供一些帮助：

这是我的错误，跟踪：

VelocityView : Error processing a template for path '/comptes/affilies.html.vtl'
Invocation of method 'getRemunerationVendeur' in class model.User threw exception java.lang.NullPointerException at /comptes/affilies.html.vtl[line 28, column 20]


    java.lang.NullPointerException
        at model.User.getListRemunerationVendeur(User.java:238)
        at model.User.getRemunerationVendeur(User.java:268)
        at sun.reflect.GeneratedMethodAccessor75.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.velocity.runtime.parser.node.PropertyExecutor.execute(PropertyExecutor.java:127)
        at org.apache.velocity.util.introspection.UberspectImpl$VelGetterImpl.invoke(UberspectImpl.java:523)
        at org.apache.velocity.runtime.parser.node.ASTIdentifier.execute(ASTIdentifier.java:198)
        at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:271)
        at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:561)
        at org.apache.velocity.runtime.directive.VelocimacroProxy.handleArgValues(VelocimacroProxy.java:325)
        at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:189)
        at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:300)
        at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230)
        at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
        at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
        at org.apache.velocity.runtime.directive.Foreach.renderBlock(Foreach.java:281)
        at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:258)
        at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
        at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
        at org.apache.velocity.Template.merge(Template.java:356)
        at org.apache.velocity.Template.merge(Template.java:260)
        at org.apache.velocity.tools.view.VelocityView.performMerge(VelocityView.java:942)
        at org.apache.velocity.tools.view.VelocityView.merge(VelocityView.java:902)
        at org.apache.velocity.tools.view.VelocityViewServlet.mergeTemplate(VelocityViewServlet.java:318)
        at org.apache.velocity.tools.view.VelocityViewServlet.doRequest(VelocityViewServlet.java:220)
        at org.apache.velocity.tools.view.VelocityViewServlet.doGet(VelocityViewServlet.java:182)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:120)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:97)
        at com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:109)
        at filter.AuthFilter.doRedirect(AuthFilter.java:54)
        at velosurf.web.auth.AuthenticationFilter.doFilter(AuthenticationFilter.java:392)
        at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:89)
        at filter.DateFilter.doFilter(DateFilter.java:309)
        at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:89)
        at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:156)
        at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:289)
        at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:838)
        at com.caucho.network.listen.TcpSocketLink.dispatchRequest(TcpSocketLink.java:1345)
        at com.caucho.network.listen.TcpSocketLink.handleRequest(TcpSocketLink.java:1301)
        at com.caucho.network.listen.TcpSocketLink.handleRequestsImpl(TcpSocketLink.java:1285)
        at com.caucho.network.listen.TcpSocketLink.handleRequests(TcpSocketLink.java:1193)
        at com.caucho.network.listen.TcpSocketLink.handleAcceptTaskImpl(TcpSocketLink.java:992)
        at com.caucho.network.listen.ConnectionTask.runThread(ConnectionTask.java:117)
        at com.caucho.network.listen.ConnectionTask.run(ConnectionTask.java:93)
        at com.caucho.network.listen.SocketLinkThreadLauncher.handleTasks(SocketLinkThreadLauncher.java:169)
        at com.caucho.network.listen.TcpSocketAcceptThread.run(TcpSocketAcceptThread.java:61)
        at com.caucho.env.thread2.ResinThread2.runTasks(ResinThread2.java:173)
        at com.caucho.env.thread2.ResinThread2.run(ResinThread2.java:118) 

Normally the class User.java works.

This is a piece of my class java (User.java) that corresponds to my error :

    Instance service = (Instance)db.get("service_by_code");
    vendeur.put("ope_code", operateur.get("ope_code"));
    vendeur.put("srv_code", service.get("srv_code"));

我的变量服务对应于数据库中的一行结果

我认为我的行在数据库中是空的（因为nullPointerException主要是指…设置为空的对象！），但我不知道如何解决数据库中的问题：更改数据库行中的值

我试过了，但没什么变化

如果你有什么建议，请告诉我

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Ale。

由于您使用DB，类实例的对象看起来是空的。

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无论如何，如果你给出一个异常的堆栈跟踪应该很好，这样就没有人会去猜测了。

你可以在开始将项目放入之前检查它是否为

null

，这真的是一个速度问题吗？这听起来更像是你的数据库逻辑。我给了你我的完整跟踪。