Question

我有Mysql数据库，并且正在使用servlet：这是我的表架构：

 CREATE TABLE Files (
 File_Name               VARCHAR(50),
 File_Data                Blob ,
 File_Date          VARCHAR(20),
 File_Course_Code       VARCHAR(45) REFERENCES Course(Course_Code) ,
 PRIMARY KEY (File_Name , File_Date, File_Course_Code)
  );

这是servlet代码：

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html;charset=UTF-8");
    ServletOutputStream os = response.getOutputStream();
    try {
        InputStream uploadedFile = null;

        DiskFileUpload fu = new DiskFileUpload();
        // If file size exceeds, a FileUploadException will be thrown
        fu.setSizeMax(10000000);

        List fileItems = fu.parseRequest(request);
        Iterator itr = fileItems.iterator();

        while (itr.hasNext()) {
            FileItem fi = (FileItem) itr.next();

            //Check if not form field so as to only handle the file inputs
            //else condition handles the submit button input
            if (!fi.isFormField()) {  // If the form fiel is a file
                uploadedFile = fi.getInputStream();
            }
        }

            // to get the file name:
            String fileName= "String";



            // to extract the date:
            java.util.Date now = new java.util.Date();
            String DATE_FORMAT = "yyyy-MM-dd hh:mm:ss";
            SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT);
            String strDateNew = sdf.format(now);


            HttpSession session = request.getSession();
            String a = (String) session.getAttribute("fileccode");



            // set connection up: 
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/VC", "root", "");
            PreparedStatement stmt = null;
            stmt = conn.prepareStatement("INSERT INTO Files (File_Name,File_Data,File_Date,File_Course_Code) VALUES (?,? ?,?)");
                  stmt.setString(1,fileName);
            stmt.setBinaryStream(2,uploadedFile);
                  stmt.setString(3,strDateNew);
                  stmt.setString(4,a);
            stmt.executeUpdate();



    } catch (FileUploadException e) {
        os.print(e.getLocalizedMessage());
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        os.close();
    }
}

我看过很多关于此错误的帖子，但几乎所有帖子在编写查询时都出现语法错误。我相信我没有语法错误。但也许（File_Data）作为主键，默认null会出错？

Answer 1

您错过了逗号

VALUES (?,? ?,?)

应该是

VALUES (?,?,?,?)

严重：java.sql.SQLException：列计数与第1行的值计数不匹配

1 个答案: