尝试将JTable导出到Excel文件时出错

编程问答 2022-08-12

问题描述

我试图将JTable导出到Excel文件中，但是我访问的每个站点和论坛总是遇到类似的错误。

在这里我调用函数：（注释重要的行）

try {
        exportTable(table,new File("C:\\Test\\TA\\Data\\tables.xls")); //THIS IS LINE 99
    } catch (IOException e1) {
            
        e1.printstacktrace();
    }

函数在这里：

第220行的代码类似于我尝试过的许多不同方法，但始终都是似乎会导致错误的代码，经过测试，我仍然找不到解决方法。

public void exportTable(JTable table,File file) throws IOException {
        TableModel model = table.getModel();
        FileWriter out = new FileWriter(file);
        for(int i=0; i < model.getColumnCount(); i++) {
    out.write(model.getColumnName(i) + "\t");
        }
        out.write("\n");

        for(int i=0; i< model.getRowCount(); i++) {
    for(int j=0; j < model.getColumnCount(); j++) {
        out.write(model.getValueAt(i,j).toString()+"\t"); //THIS IS LINE 220
        }
        out.write("\n");
    }

    out.close();
    System.out.println("write out to: " + file);
}

无论尝试哪种方式，我总是会遇到相同的错误：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at testing.TableExample2.exportTable(TableExample2.java:220)
    at testing.TableExample2$4.actionPerformed(TableExample2.java:99)
    at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)
    at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)
    at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
    at java.desktop/javax.swing.DefaultButtonModel.setpressed(DefaultButtonModel.java:262)
    at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
    at java.desktop/java.awt.Component.processMouseEvent(Component.java:6631)
    at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
    at java.desktop/java.awt.Component.processEvent(Component.java:6396)
    at java.desktop/java.awt.Container.processEvent(Container.java:2263)
    at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5007)
    at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
    at java.desktop/java.awt.Component.dispatchEvent(Component.java:4839)
    at java.desktop/java.awt.Lightweightdispatcher.retargetMouseEvent(Container.java:4918)
    at java.desktop/java.awt.Lightweightdispatcher.processMouseEvent(Container.java:4547)
    at java.desktop/java.awt.Lightweightdispatcher.dispatchEvent(Container.java:4488)
    at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)
    at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2772)
    at java.desktop/java.awt.Component.dispatchEvent(Component.java:4839)
    at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
    at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
    at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
    at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
    at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
    at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
    at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
    at java.desktop/java.awt.EventdispatchThread.pumpOneEventForFilters(EventdispatchThread.java:203)
    at java.desktop/java.awt.EventdispatchThread.pumpEventsForFilter(EventdispatchThread.java:124)
    at java.desktop/java.awt.EventdispatchThread.pumpEventsForHierarchy(EventdispatchThread.java:113)
    at java.desktop/java.awt.EventdispatchThread.pumpEvents(EventdispatchThread.java:109)
    at java.desktop/java.awt.EventdispatchThread.pumpEvents(EventdispatchThread.java:101)
    at java.desktop/java.awt.EventdispatchThread.run(EventdispatchThread.java:90)

解决方法

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