如何在Java程序（J2EE + JSTL）中获取服务器文件夹的路径 [英] how to get the path of server's folder inside Java program (J2EE + JSTL)

问题描述

我想在基于Web的项目（J2EE-JSP + Servlets）中读取Excel文件的内容，这些项目位于Web服务器的文件夹中。

I wanted to read contents of Excel files in my web-based project (J2EE-JSP+Servlets) which are located inside the web server's folder.

我有制作了一个java文件，我将使用JSTL库通过JSP页面调用，但是我需要在Java文件中获取Excel工作表的路径，这样我才能阅读内容。

I have made a java file, which i will call through a JSP page using JSTL library, but I need to get the path of the Excel sheet in the Java file, so I can read the contents.

如何获取当前Java文件的路径以及Excel文件？

How can I get the path to the current Java file and so the Excel file?

此外，我将通过以下方式读取Excel文件的内容POI库。我能够在J2SE开发中做到这一点，但这可能吗？

Also, I will be reading the contents of the Excel file through POI library. I was able to do this in J2SE development, but is it possible here?

POIFSFileSystem fs = null;
    try {
        fs = new POIFSFileSystem(new FileInputStream("**some path here of sheet**"));
    } catch (FileNotFoundException ex) {
        ex.printStackTrace();
    } catch (IOException ex) {
        ex.printStackTrace();
    }
    HSSFWorkbook wb = null;
    try {
        wb = new HSSFWorkbook(fs);
    } catch (IOException ex) {
        ex.printStackTrace();
    }
    HSSFSheet sheet = wb.getSheetAt(0);
    HSSFRow row;
    HSSFCell cell1,cell2,cell3; 

    int rows; // No of rows, stores the no. of rows for an excel sheet
    int cols; // No of columns, stores the no. of columns for an excel sheet

    rows = sheet.getPhysicalNumberOfRows();
    cols = 5;

    for(int r = 0; r < rows; r++) {
        row = sheet.getRow(r);

        if(row != null) {
            cell1 = row.getCell(1);
            cell2 = row.getCell(2);
            cell3 = row.getCell(4);

            //System.out.println(cell1.getStringCellValue()+" "+cell2.getStringCellValue()+" "+cell3.getStringCellValue());                
        }
    }
}

推荐答案

您可以要求servlet上下文相对于实际路径进行转换：

You can ask servlet context to translate relative to real path:

context.getRealPath("/");

如果java类是servlet，你可能会做类似

If you java class is servlet, you can probably do something like

getServletConfig().getServletContext();

否则，jsp页面是一个servlet，所以你可以从那里传递它。

otherwise, jsp page is a servlet, so you can pass it from there.

最后，您可以在启动应用程序时选择一次：

Finally, you can pick it up once when you start your app:

public class AppStartup implements ServletContextListener {

    public void contextDestroyed(ServletContextEvent event) {
    }

    public void contextInitialized(ServletContextEvent event) {
        ServletContext context = event.getServletContext();
        // remember it in some static class for future use
    }
}

说完这一切之后，最好是创建一个具有servlet上下文，解析路径，并使用已解析的文件路径调用类的servlet，最后将请求转发到jsp页面以显示结果。

Having said all this, it's probably better to make a servlet that has his servlet context, resolve path, and call your class with resolved path to a file, then finally forward request to a jsp page to display results.

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