Question

我正在尝试使用在java中创建的表单将条目插入数据库。我可以毫无问题地从数据库中进行选择，但是我很难插入它。我认为，问题在于我没有正确地转换整数，或者SQL不会将int插入到Number字段中。我不确定。我一直收到“AWT-EventQueue-0”错误，但它没有指定位置。

以下是我的代码片段，用于转换输入文字：

public void addItem() throws ClassNotFoundException, SQLException{
    Item i1;
    DataAccess DA = new DataAccess();
    this.txtOutput.setText(DA.testResult);
    i1 = new Item();
    i1.setItemId(Integer.parseInt(this.txtItemId.getText()));
    i1.setCategoryId(Integer.parseInt(this.txtCategoryId.getText()));
    i1.setItemName(this.txtItemName.getText());
    i1.setItemDesc(this.txtItemDesc.getText());
    i1.setUnitPrice(Integer.parseInt(this.txtUnitPrice.getText()));
    i1.setUnitStock(Integer.parseInt(this.txtUnitStock.getText()));
    try {
        i1.saveItem();
    } catch (ClassNotFoundException | SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    this.txtItemId.setText("");
    this.txtCategoryId.setText("");
    this.txtItemName.setText("");
    this.txtItemDesc.setText("");
    this.txtUnitPrice.setText("");
    this.txtUnitStock.setText("");
}

此外，这是我用来将数据插入我的数据库的代码：

public int saveItem() throws ClassNotFoundException, SQLException{
    int rowsAffected=0;
    String strSQL = "INSERT INTO item VALUES (sc_item_item_id_seq.NEXTVAL," + this.getCategoryId() + ",'" + this.getItemName() + "','" + this.getItemDesc() + "'," + this.getUnitPrice() + "," + this.getUnitStock() + ")";
    DataAccess DA = new DataAccess();
    rowsAffected = DA.modifyDatabase(strSQL);
    return rowsAffected;
}

就像我说的那样，我试图将整数输入到我的数据库中类型为Number的字段中。这是可行的，还是我弄错了？

另外值得注意的是，我在另一个表上没有问题，但该表只接受字符串。

任何帮助都将不胜感激。

谢谢！

编辑：

这是错误：

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at javagui.views.frmItem.addItem(frmItem.java:243)
at javagui.views.frmItem$1.actionPerformed(frmItem.java:101)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

是的，你正确地做到了;插入不带引号的数字类型值。但是，我认为您的错误来自于您Integer.parseInt()中的addItem()。请检查您尝试解析为int的所有字符串是否都没有错误。您还应该将这些Integer.parseInt()语句放在try/catch(NumberFormatException)块中以捕获这些转换错误。

此外，由于您正在查找要查找的异常的try/catch，因此您无需指定函数在函数头中引发的内容。那就是告诉上层调用函数“嘿，我可能抛出这些异常，所以你需要抓住它们。”

Answer 2

尝试阅读并理解堆栈跟踪。

它告诉您输入字符串NumberFormatException的问题是""：

java.lang.NumberFormatException: For input string: ""

，在致电Integer.parseInt时发生：

at java.lang.Integer.parseInt(Unknown Source)

在您的班级addItem的方法frmItem中，位于frmItem.java文件的第243行：

at javagui.views.frmItem.addItem(frmItem.java:243)

因此它与数据库无关：您将空字符串传递给parseInt。错误消息和堆栈跟踪非常有用：您必须阅读它们并尝试理解它们。

有问题正确地将String转换为int以插入到字段类型为Number的SQL数据库中

2 个答案: