while循环产生的错误，这段代码有啥问题？
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【中文标题】while循环产生的错误，这段代码有啥问题？【英文标题】：Error produced from while loop, whats wrong with this code?while循环产生的错误，这段代码有什么问题？ 【发布时间】：2018-09-28 21:50:50 【问题描述】：我仍在学习 Java，并且正在使用场景构建器。每次我输入一个不在网站上的值时，它都会从中提取数据，我会收到此错误。我已经玩了好几个小时试图解决它，这让我很头疼。当我输入站点中存在的值时，我没有收到任何错误，但是当我在文本字段中输入不在站点中的内容时，我会收到该错误。
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8411)
at com.sun.javafx.scene.control.behavior.TextFieldBehavior.fire(TextFieldBehavior.java:179)
at com.sun.javafx.scene.control.behavior.TextInputControlBehavior.callAction(TextInputControlBehavior.java:178)
at com.sun.javafx.scene.control.behavior.BehaviorBase.callActionForEvent(BehaviorBase.java:218)
at com.sun.javafx.scene.control.behavior.TextInputControlBehavior.callActionForEvent(TextInputControlBehavior.java:127)
at com.sun.javafx.scene.control.behavior.BehaviorBase.lambda$new$74(BehaviorBase.java:135)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$KeyHandler.process(Scene.java:3964)
at javafx.scene.Scene$KeyHandler.access$1800(Scene.java:3910)
at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2040)
at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2501)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:217)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:149)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$352(GlassViewEventHandler.java:248)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:247)
at com.sun.glass.ui.View.handleKeyEvent(View.java:546)
at com.sun.glass.ui.View.notifyKey(View.java:966)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
... 46 more
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -2
at java.lang.String.substring(String.java:1967)
at sample.testController.findID(testController.java:85)
at sample.testController.search(testController.java:39)
... 56 more
这是我的控制器文件
package sample;
import javafx.scene.control.Label;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.scene.control.Button;
import java.awt.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import javafx.scene.control.TextField;
public class testController
@FXML
private Button Hiscores;
@FXML
private TextField geSearch;
@FXML
private Label Price;
Items item = new Items();
public void search() throws MalformedURLException, IOException
BufferedReader br = null;
String itemName = geSearch.getText();
item.setName(itemName);
item.test();
findID();
System.out.println("MAde it");
System.out.println(item.getId());
if(item.getId().equalsIgnoreCase(""))
Price.setText("Item not found");
else
String u = "http://services.runescape.com/m=itemdb_oldschool/api/catalogue/detail.json?item=" + item.getId();
URL url = new URL(u);
br = new BufferedReader(new InputStreamReader(url.openStream()));
String line = "";
line = br.readLine();
String lineSplit;
String result = line.substring(line.indexOf(",\"price\":") + 9, line.indexOf(",\"today\""));
if (result.contains("\""))
result = result.substring(1, result.length() - 1);
Price.setText(result);
public void findID() throws IOException
BufferedReader br = null;
try
String u = "https://pastebin.com/raw/LhxJ7GRG";
URL url = new URL(u);
br = new BufferedReader(new InputStreamReader(url.openStream()));
String line = "";
int counter = 0;
String next;
while ((line = br.readLine()) != null)
if(counter >= 2)
next = br.readLine();
System.out.println("Current Line: " + line);
System.out.println("Next Line: " + next);
String tester = next.substring(next.indexOf(": \"") + 3, next.length() - 1);
if (geSearch.getText().equalsIgnoreCase(tester))
item.setName(geSearch.getText());
item.setId(line.substring(line.indexOf(": ") + 2, line.length() - 1));
break;
item.setId("");
Price.setText("");
counter++;
catch (MalformedURLException e)
System.out.println("Error");
public void changeScene() throws Exception
Stage primaryStage = (Stage) Hiscores.getScene().getWindow();
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setScene(new Scene(root, 500, 600));
primaryStage.show();
正如 Andreas 指出的那样，也许我的问题出在测试仪上，但当我尝试此解决方案时，这并没有奏效。
if( counter < 12045)
tester = next.substring(next.indexOf(": \"") + 3, next.length() - 1);
else
tester = "";
【问题讨论】：
第 85 行是什么？ 当: " 在next 中的文本中不存在时，您认为next.indexOf(": \"") 会返回什么？
I downvoted because there was no effort to debug the code，或者至少你没有分享调试时发现的信息。
@Andreas 哦，这可能是问题所在，只是当项目存在时，在找到它之前，它在整个列表中都没有问题。
你还没有告诉我们哪一行是第85行，哪里出错了。 --- 您也没有共享您拥有的调试信息，即错误发生时next 和/或line 的值，并且您确实打印了这些行，所以您应该知道它们的值是什么。
【参考方案1】：
java.lang.StringIndexOutOfBoundsException：字符串索引超出范围：-2
您正在尝试引用不包含在字符串中的索引。
我认为问题可能出在next.indexOf(": \"") + 3
【讨论】：
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