我正在尝试获取ComboBox的值并将其存储到数据库中。但是我得到这个错误：
Executing F:\eLibraryServer\dist\run2044401483\eLibraryServer.jar using platform C:\Program Files\Java\jdk1.8.0_151\jre/bin/java
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:8413)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$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:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$353(GlassViewEventHandler.java:417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._enterNestedEventLoopImpl(Native Method)
at com.sun.glass.ui.win.WinApplication._enterNestedEventLoop(WinApplication.java:204)
at com.sun.glass.ui.Application.enterNestedEventLoop(Application.java:511)
at com.sun.glass.ui.EventLoop.enter(EventLoop.java:107)
at com.sun.javafx.tk.quantum.QuantumToolkit.enterNestedEventLoop(QuantumToolkit.java:583)
at javafx.stage.Stage.showAndWait(Stage.java:474)
at elibraryserver.NewStudentController.initRegister(NewStudentController.java:152)
at elibraryserver.serverController.addStudentButtonAction(serverController.java:71)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(ContextMenuContent.java:1405)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren$343(ContextMenuContent.java:1358)
at com.sun.javafx.event.CompositeEventHandler$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.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$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$353(GlassViewEventHandler.java:417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769)
... 106 more
Caused by: java.lang.NumberFormatException: For input string: "cmbCourse"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.valueOf(Integer.java:766)
at elibraryserver.NewStudentController.registerButtonAction(NewStudentController.java:180)
使用此代码时：
String query = ("INSERT INTO tblusers (first_name, middle_initial, last_name, username, password,"
+ " privilege) VALUES (?,?,?,?,?,?)");
stmt = conn.prepareStatement(query, Statement.RETURN_GENERATED_KEYS);
stmt.setString(1, txtFn.getText());
stmt.setString(2, txtMi.getText());
stmt.setString(3, txtLn.getText());
stmt.setString(4, txtUser.getText());
stmt.setString(5, txtPass.getText());
stmt.setString(6, "student");
stmt.executeUpdate();
ResultSet rs = stmt.getGeneratedKeys();
Integer key =- 1;
if (rs.next()) {
key = rs.getInt(1);
}
String query2 = ("INSERT INTO tblcourseinfo (user_id, course_id, school_id) VALUES (?,?,?)");
stmt = conn.prepareStatement(query2);
stmt.setInt(1, key);
stmt.setInt(2, Integer.valueOf(cmbCourse.getId()));
stmt.setInt(3, Integer.valueOf(cmbSchool.getId()));
stmt.executeUpdate();
NumberFormatException是什么意思？我是否在这里为ComboBoxes添加另一个insert语句，将值插入到另一个表中？插入的数据应该是我的ComboBoxes的外键。
编辑：事实证明，它确实打印出了变量名而不是ID。
cmbCourse.getId(): cmbCourse
cmbSchool.getId(): cmbSchool
这是我的ComboBoxes的简单填充方法
public void populateCourse() {
QueryCourses qc = new QueryCourses();
HashMap<String, Integer> map = qc.hashMap();
cmbCourse.getItems().setAll(map.keySet());
}
与查询QueryCourses.java
public class QueryCourses {
Statement stmt = null;
Connection conn = null;
ResultSet rs = null;
public HashMap<String, Integer> hashMap(){
HashMap<String, Integer> map = new HashMap<>();
conn = DbConnection.ConnectDB();
try {
stmt = conn.createStatement();
String qry = "SELECT `course_id`, `course_title` FROM `tblcourses`";
rs = stmt.executeQuery(qry);
Courses crse;
while (rs.next()) {
crse = new Courses(rs.getInt(1), rs.getString(2));
map.put(crse.getCourseTitle(), crse.getCourseId());
}
} catch (SQLException ex) {
Logger.getLogger(NewStudentController.class.getName()).log(Level.SEVERE, null, ex);
}
return map;
}
}
最佳答案
您的HashMap声明
HashMap<String, Integer> map = new HashMap<>();
您尝试用String键填充地图。
map.put(crse.getCourseTitle(), crse.getCourseId());
您用字符串类型键集构造您的组合框。
cmbCourse.getItems().setAll(map.keySet());
现在，您从组合框中获取了值，然后它从String中返回了不可转换为数字值的String。
更新：
public class Courses {
private int id;
private String title;
public Courses (int id, String name) {
this.id = id;
this.title = name;
}
public int getId() {
return id;
}
public String getTitle() {
return title;
}
public String toString() {
return title;
}
}
try {
stmt = conn.createStatement();
String qry = "SELECT `course_id`, `course_title` FROM `tblcourses`";
rs = stmt.executeQuery(qry);
Courses crse;
while (rs.next()) {
crse = new Courses(rs.getInt(1), rs.getString(2));
cmbCourse.addItem(crse); //you directly add item in combo course.
// overload the toString of Course class.
}
} catch (SQLException ex) {
Logger.getLogger(NewStudentController.class.getName()).log(Level.SEVERE, null, ex);
}
String query = ("INSERT INTO tblusers (first_name, middle_initial, last_name, username, password,"
+ " privilege) VALUES (?,?,?,?,?,?)");
stmt = conn.prepareStatement(query, Statement.RETURN_GENERATED_KEYS);
stmt.setString(1, txtFn.getText());
stmt.setString(2, txtMi.getText());
stmt.setString(3, txtLn.getText());
stmt.setString(4, txtUser.getText());
stmt.setString(5, txtPass.getText());
stmt.setString(6, "student");
stmt.executeUpdate();
ResultSet rs = stmt.getGeneratedKeys();
Integer key =- 1;
if (rs.next()) {
key = rs.getInt(1);
}
String query2 = ("INSERT INTO tblcourseinfo (user_id, course_id, school_id) VALUES (?,?,?)");
stmt = conn.prepareStatement(query2);
stmt.setInt(1, key);
Course cr =(Course)cmbCourse.getSelectedItem();
stmt.setInt(2, cr.getId());
School cs =(School)cmbSchool.getSelectedItem();
stmt.setInt(3, Integer.valueOf(cs.getId());
stmt.executeUpdate();
更新：使用HashMap
QueryCourses qc = new QueryCourses();
HashMap<String, Integer> map = qc.hashMap();
//get the course title from combo box.
String courseTitle = (String) cmbCourse.getSelectedItem();
String school = (String) cmbSchool.getSelectedItem();
//get value(id) from course HashMap with key <courseTitle>
stmt.setInt(2, map.get(courseTitle));
//do same for school