如何解决NumberFormatException？ [重复]

Question

这个问题在这里已有答案：

• Jackcess Numberformatexception 2回答

我是Java的新手，所以请耐心等待......我正在尝试使用Jackcess库将数据从CSV文件写入Access数据库。 CSV文件的第一行完美地写入数据库，但从第二行开始，它不断抛出NumberFormatException。这是代码：

public void GPXtoAccess() {
    try {
        Access = new Scanner(DummyCSV);
        Access.useDelimiter(";");
        while(Access.hasNextLine()) {
            GPXlat = Access.next();
            GPXlon = Access.next();
            GPXtime = Access.next();
            GPXname = Access.next();
            GPXdesc = Access.next();

            try {
                GPXTable.addRow(Column.AUTO_NUMBER, GPXlat, GPXlon, GPXtime, GPXname, GPXdesc);
            } catch (IOException E) {
                System.out.println("Error: " + E);
                System.out.println("Error is thrown while writing data to table");
            }
        }
    } catch (FileNotFoundException ex) {
        System.out.println("Error: " + ex);
    }
}

它不断抛出NumberFormatException：

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "2016-11-28T11:36:34"
at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043)
at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
at java.lang.Double.parseDouble(Double.java:538)
at java.lang.Double.valueOf(Double.java:502)
at com.healthmarketscience.jackcess.impl.ColumnImpl.toNumber(ColumnImpl.java:1443)
at com.healthmarketscience.jackcess.impl.ColumnImpl.writeFixedLengthField(ColumnImpl.java:1105)
at com.healthmarketscience.jackcess.impl.ColumnImpl.writeFixedLengthField(ColumnImpl.java:1072)
at com.healthmarketscience.jackcess.impl.ColumnImpl.writeRealData(ColumnImpl.java:1029)
at com.healthmarketscience.jackcess.impl.ColumnImpl.write(ColumnImpl.java:1021)
at com.healthmarketscience.jackcess.impl.ColumnImpl.write(ColumnImpl.java:1003)
at com.healthmarketscience.jackcess.impl.TableImpl.createRow(TableImpl.java:2708)
at com.healthmarketscience.jackcess.impl.TableImpl.createRow(TableImpl.java:2660)
at com.healthmarketscience.jackcess.impl.TableImpl.addRows(TableImpl.java:2193)
at com.healthmarketscience.jackcess.impl.TableImpl.addRow(TableImpl.java:2086)
at GPX.GPX_Parser.GPXtoAccess(GPX_Parser.java:196)
at GPX.GUI.GPX_Handle.btnExportDatabaseActionPerformed(GPX_Handle.java:234)
at GPX.GUI.GPX_Handle.access$300(GPX_Handle.java:21)
at GPX.GUI.GPX_Handle$4.actionPerformed(GPX_Handle.java:111)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Answer 1

我相信这里发生的事情是你的GPXTime不符合Access数据库标准，所以它不知道如何处理它。您可能希望查看apis并查看它采用的格式，然后从具有格式“2016-11-28T11：36：34”的csv文件转换为Access数据库接受的任何格式。在调用addRow（）之前将日期转换为毫秒来尝试

Answer 2

不用担心，我们都是从知识有限开始的。

我首先给出一些关于代码的反馈：

1）你似乎有很多成员变量，甚至可能是静态的。例如变量Access。如果您只在与我们共享的范围内使用它，即在该方法中，则没有理由这样做。

2）java命名约定：我强烈建议你遵循java命名约定，如下所述：http://www.oracle.com/technetwork/java/codeconventions-135099.html遵循这些命名约定使代码对其他人更具可读性，例如：我们，在这里

3）在获取next（）之前，你应该使用hasNext（）来确保实际上有一个可用的令牌。我建议你尝试调试并修复你的问题：

while (Access.hasNext()) {
    System.out.println(Access.next());
}

看看情况如何。