request.getParameter（）は、1つのパラメータを除いてサーブレットでnullを返します

Question

私はフォームから値を取得しようとしていますが、私はインターネット上で見つけることができたすべてを試しましたが、 .getParameter（）は "bulkname"の値だけを返し、他のすべての変数は私にnullを与えます、なぜか分かりません。

このフォームはユーザーからの値を受け取り、サーブレットに送信する必要があります。そのため、値とファイルをデータベースに挿入できます。

これは私のコードです。

bulkCheckServlet.java

/* 
 * To change this license header, choose License Headers in Project Properties. 
 * To change this template file, choose Tools | Templates 
 * and open the template in the editor. 
 */ 
package source; 
  
import java.io.IOException; 
import java.io.InputStream; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.PreparedStatement; 
import java.sql.SQLException; 
import java.time.LocalDateTime; 
  
import javax.servlet.ServletException; 
import javax.servlet.annotation.MultipartConfig; 
import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import javax.servlet.http.Part; 
  
/** 
 * 
 * @author Farouk 
 */ 
@WebServlet(name = "bulkCheckServlet", urlPatterns = {"/bulkCheckServlet"}) 
@MultipartConfig 
public class bulkCheckServlet extends HttpServlet { 
  
    protected void doGet(HttpServletRequest request, HttpServletResponse response) 
      throws ServletException, IOException { 
  
      String bulkname = request.getParameter("bulkname"); 
      String quota = request.getParameter("quota");//Integer.parseInt(request.getParameter("quota")); 
      System.out.println(quota); 
      String provider = request.getParameter("provider"); 
  
      InputStream inputStream = null; // input stream of the upload file 
  
      // obtains the upload file part in this multipart request 
      Part filePart = request.getPart("file"); 
      if (filePart != null) { 
       // prints out some information for debugging 
       System.out.println(filePart.getName()); 
       System.out.println(filePart.getSize()); 
       System.out.println(filePart.getContentType()); 
  
       // obtains input stream of the upload file 
       inputStream = filePart.getInputStream(); 
      } 
  
      Connection conn = null; // connection to the database 
      String message = null; // message will be sent back to client 
  
      try { 
       // connects to the database 
       DriverManager.registerDriver(new com.mysql.jdbc.Driver()); 
       conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/smsglobal", "root", "123456789"); 
  
       // constructs SQL statement 
       String sql = "INSERT INTO smsbulk (id,quota,provider,bulkname,date,file) values (1,?,?,?,?,?);"; 
       PreparedStatement statement = conn.prepareStatement(sql); 
       statement.setString(1, quota); 
       statement.setString(2, provider); 
       statement.setString(3, bulkname); 
       statement.setString(4, LocalDateTime.now().toString()); 
       System.out.println(sql); 
  
       if (inputStream != null) { 
        // fetches input stream of the upload file for the blob column 
        statement.setBlob(5, inputStream); 
       } 
  
       // sends the statement to the database server 
       int row = statement.executeUpdate(); 
       if (row > 0) { 
        message = "File uploaded and saved into database"; 
       } 
      } catch (SQLException ex) { 
       message = "ERROR: " + ex.getMessage(); 
       ex.printStackTrace(); 
      } finally { 
       if (conn != null) { 
        // closes the database connection 
        try { 
         conn.close(); 
        } catch (SQLException ex) { 
         ex.printStackTrace(); 
        } 
       } 
       // sets the message in request scope 
       request.setAttribute("Message", message); 
  
       // forwards to the message page 
       getServletContext().getRequestDispatcher("/Campaign.jsp").forward(request, response); 
      } 
    } 
  
    /** 
  * Handles the HTTP <code>POST</code> method. 
  * 
  * @param request servlet request 
  * @param response servlet response 
  * @throws ServletException if a servlet-specific error occurs 
  * @throws IOException if an I/O error occurs 
  */ 
    @Override 
    protected void doPost(HttpServletRequest request, HttpServletResponse response) 
      throws ServletException, IOException { 
     doGet(request, response); 
    } 
} 

なtest.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%> 
<!DOCTYPE html> 
<html> 
    <head> 
     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
     <title>Test</title> 
    </head> 
    <body> 
     <form action="bulkCheckServlet" method="post" enctype="multipart/form-data"> 
      Provider 
      <br/> 
      <input type="text" id="provider" name="provider"/> 
      <br/> 
      <br/> 
      Bulk Name 
      <br/> 
      <input type="text" name="bulkname" id="bulkname"/> 
      <br/> 
      <br/> 
      Quota 
      <br/> 
      <input type="text" name="quota" id="quota"/> 
      <br/> 
      <br/> 
      File 
      <br/> 
      <input type="file" name="file" id="file"/> 
      <br/> 
      <input type="submit" value="Submit" /> 
      <br/> 
     </form> 
    </body> 
</html> 

Answer 1

サーブレットを次のコードに置き換えてください。これは完全に役立ちます。

/* 
    * To change this license header, choose License Headers in Project Properties. 
    * To change this template file, choose Tools | Templates 
    * and open the template in the editor. 
    */ 
    package source; 

    import java.io.IOException; 
    import java.io.InputStream; 
    import java.sql.Connection; 
    import java.sql.DriverManager; 
    import java.sql.PreparedStatement; 
    import java.sql.SQLException; 
    import java.time.LocalDateTime; 

    import javax.servlet.ServletException; 
    import javax.servlet.annotation.MultipartConfig; 
    import javax.servlet.annotation.WebServlet; 
    import javax.servlet.http.HttpServlet; 
    import javax.servlet.http.HttpServletRequest; 
    import javax.servlet.http.HttpServletResponse; 
    import javax.servlet.http.Part; 

    /** 
    * 
    * @author Farouk 
    */ 
    @WebServlet(name = "bulkCheckServlet", urlPatterns = {"/bulkCheckServlet"}) 
    @MultipartConfig 
    public class bulkCheckServlet extends HttpServlet { 

     protected void doGet(HttpServletRequest request, HttpServletResponse response) 
       throws ServletException, IOException { 

       String bulkname = request.getParameter("bulkname"); 
       String quota = request.getParameter("quota");//Integer.parseInt(request.getParameter("quota")); 
       System.out.println(quota); 
       String provider = request.getParameter("provider"); 

       InputStream inputStream = null; // input stream of the upload file 

       // obtains the upload file part in this multipart request 
       Part filePart = request.getPart("file"); 
       if (filePart != null) { 
        // prints out some information for debugging 
        System.out.println(filePart.getName()); 
        System.out.println(filePart.getSize()); 
        System.out.println(filePart.getContentType()); 

        // obtains input stream of the upload file 
        inputStream = filePart.getInputStream(); 
       } 

       Connection conn = null; // connection to the database 
       String message = null; // message will be sent back to client 

       try { 
        // connects to the database 
        DriverManager.registerDriver(new com.mysql.jdbc.Driver()); 
        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/smsglobal", "root", "0168308330"); 

        // constructs SQL statement 
        String sql = "INSERT INTO smsbulk (id,quota,provider,bulkname,date,file) values (?,?,?,?,?,?);"; 
        PreparedStatement statement = conn.prepareStatement(sql); 
        statement.setString(1, quota); 
        statement.setString(2, provider); 
        statement.setString(3, bulkname); 
        statement.setString(4, LocalDateTime.now().toString()); 
        System.out.println(sql); 

        if (inputStream != null) { 
         // fetches input stream of the upload file for the blob column 
         statement.setBlob(5, inputStream); 
        } 

        // sends the statement to the database server 
        int row = statement.executeUpdate(); 
        if (row > 0) { 
         message = "File uploaded and saved into database"; 
        } 
       } catch (SQLException ex) { 
        message = "ERROR: " + ex.getMessage(); 
        ex.printStackTrace(); 
       } finally { 
        if (conn != null) { 
         // closes the database connection 
         try { 
          conn.close(); 
         } catch (SQLException ex) { 
          ex.printStackTrace(); 
         } 
        } 
        // sets the message in request scope 
        request.setAttribute("Message", message); 

        // forwards to the message page 
        getServletContext().getRequestDispatcher("/Campaign.jsp").forward(request, response); 
       } 
     } 

     /** 
     * Handles the HTTP <code>POST</code> method. 
     * 
     * @param request servlet request 
     * @param response servlet response 
     * @throws ServletException if a servlet-specific error occurs 
     * @throws IOException if an I/O error occurs 
     */ 
     @Override 
     protected void doPost(HttpServletRequest request, HttpServletResponse response) 
       throws ServletException, IOException { 
      doGet(request, response); 
     } 
    } 

Answer 2

の代わりにあなたのJSP

<input type="file" neme="file" id="file"/> 

使用次の行に次の行を使用して

<input type="file" name="file" id="file"/>