用Java检查文件扩展名 [英] Check file extension in Java

问题描述

我必须将数据从Excel文件导入数据库并执行此操作，我想检查所选文件的扩展名。

I have to import data from an Excel file to database and to do this, I would like to check the extension of the chosen file.

这是我的代码：

String filename = file.getName();
String extension = filename.substring(filename.lastIndexOf(".") + 1, filename.length());

String excel = "xls";
if (extension != excel) {
    JOptionPane.showMessageDialog(null, "Choose an excel file!");
}
else {
    String filepath = file.getAbsolutePath();
    JOptionPane.showMessageDialog(null, filepath);
    String upload = UploadPoData.initialize(null, filepath);

    if (upload == "OK") {
        JOptionPane.showMessageDialog(null, "Upload Successful!");
    }
}

但我总是得到：

选择一个excel文件！

Choose an excel file!

我找不到什么我的代码有问题，请有人帮忙。

I can't find what is wrong with my code, could someone please help.

推荐答案

以下

extension != excel

应该是

!excel.equals(extension)

或

!excel.equalsIgnoreCase(extension)

---

参见

• 字符串等于（）与 ==

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