java - GWT/JAVA 未捕获的异常转义

Question

我的代码有问题，但我似乎无法修复它。我想在提交按钮时将一些客户数据添加到 java/GWT 中的数组列表中。

我从中添加数据的表单。

ok.addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
            if (!voornaamTB.getText().equalsIgnoreCase("") && !achternaamTB.getText().equalsIgnoreCase("") && !emailTB.getText().equalsIgnoreCase("") && !geboortedatumTB.getText().equalsIgnoreCase("")) {
                boolean addVG;
                System.out.println(voornaamTB.getText());
                System.out.println(tussenvoegselTB.getText());
                System.out.println(achternaamTB.getText());
                System.out.println(emailTB.getText());
                System.out.println(geboortedatumTB.getText());
--> the error is generated here addVG = VGC.addVakantieganger(voornaamTB.getText(), tussenvoegselTB.getText(), achternaamTB.getText(), emailTB.getText(), geboortedatumTB.getText());
                if (addVG) {
                    Window.alert("Vakantieganger toegevoegd.");
                } else {
                    Window.alert("Vakantieganger niet toegevoegd.");
                }
            } else {
                voornaamTB.addStyleName("invalide-TextBox");
                tussenvoegselTB.addStyleName("invalide-TextBox");
                achternaamTB.addStyleName("invalide-TextBox");
                emailTB.addStyleName("invalide-TextBox");
                geboortedatumTB.addStyleName("invalide-TextBox");
            }
        }
    });

Controller 类。

import java.util.ArrayList;

import com.vakantievibes.client.domein.Vakantieganger;

public class VakantiegangerController {
    private String msg;
    private ArrayList<Vakantieganger> vakantiegangers = new ArrayList<Vakantieganger>();

    public VakantiegangerController(){

    }

@SuppressWarnings("static-access")
public boolean heeftVakantieganger(String email) {
    boolean result = false;
    for (Vakantieganger v : vakantiegangers) {
        if (v.getEmail().equalsIgnoreCase(email)){
            result = true;
        }
    }
    return result;
}

public boolean addVakantieganger(String voornaam, String tussenvoegsel, String achternaam, String email, String geboortedatum) {
    //boolean result = false;

    //if (!heeftVakantieganger(email)) {
        Vakantieganger v = new Vakantieganger(voornaam, tussenvoegsel, achternaam, email, geboortedatum);
        vakantiegangers.add(v);
        boolean result = true;
        System.out.println("klant toegevoegd");
    //}
        return result;
    }

}

使用 addVakantieganger 方法，它应该将数据添加到数组列表中。但它似乎并没有这样做，然后它应该将 true 报告回表单。 !heeftVakantieganger(email) 应该检查此人是否已经在数组列表中，但现在出于测试目的而被禁用

我在 Eclipse 中收到的错误。

14:17:03.207 [ERROR] [vakantie_vibes] Uncaught exception escaped

com.google.gwt.event.shared.UmbrellaException: One or more exceptions caught, see full set in UmbrellaException#getCauses
    at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:129)
    at com.google.gwt.user.client.ui.Widget.fireEvent(Widget.java:124)
    at com.google.gwt.event.dom.client.DomEvent.fireNativeEvent(DomEvent.java:116)
    at com.google.gwt.user.client.ui.Widget.onBrowserEvent(Widget.java:172)
    at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1321)
    at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1277)
    at sun.reflect.GeneratedMethodAccessor19.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:167)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:132)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:214)
    at sun.reflect.GeneratedMethodAccessor16.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:167)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281)
    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531)
    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352)
    at java.lang.Thread.run(Thread.java:679)
Caused by: java.lang.NullPointerException: null
    at com.vakantievibes.client.GUI.FormToevoegenVakantieganger$8.onClick(FormToevoegenVakantieganger.java:153)
    at com.google.gwt.event.dom.client.ClickEvent.dispatch(ClickEvent.java:54)
    at com.google.gwt.event.dom.client.ClickEvent.dispatch(ClickEvent.java:1)
    at com.google.gwt.event.shared.GwtEvent.dispatch(GwtEvent.java:1)
    at com.google.web.bindery.event.shared.SimpleEventBus.doFire(SimpleEventBus.java:193)
    at com.google.web.bindery.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:88)
    at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:127)
    at com.google.gwt.user.client.ui.Widget.fireEvent(Widget.java:124)
    at com.google.gwt.event.dom.client.DomEvent.fireNativeEvent(DomEvent.java:116)
    at com.google.gwt.user.client.ui.Widget.onBrowserEvent(Widget.java:172)
    at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1321)
    at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1277)
    at sun.reflect.GeneratedMethodAccessor19.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:167)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:132)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:214)
    at sun.reflect.GeneratedMethodAccessor16.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:167)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281)
    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531)
    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352)
    at java.lang.Thread.run(Thread.java:679)

Answer 1

您得到一个NullPointerException。发生这种情况是因为您使用的引用为 null。在您的情况下，这是您标记的行中的字段之一。

使用调试器，在该行上放置一个断点，然后检查 null 中的哪个字段。