java io FileNotFoundException 异常

Question

我正在尝试使用 JSP 将图像上传到 MySQL 数据库。但它以找不到文件异常结束。我该如何解决？Servlet 文件、异常和表在下面...................................... ..................................................... ..................................................... ............ 表package com.imageUpload.controller;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.sql.Connection;import java.sql.PreparedStatement;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.imageUpload.utill.DbConnection;@WebServlet("/ImageUpload")public class ImageUpload extends HttpServlet {    private static final long serialVersionUID = 1L;    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        String name=request.getParameter("name");        String image=request.getParameter("image");        FileInputStream fis=new FileInputStream(new File(image));        Connection con=DbConnection.getConnection();        try {           PreparedStatement ps=con.prepareStatement            ("insert into image(name,image)values(?,?)");        ps.setString(1,name);        ps.setBinaryStream(3, fis);        int n = ps.executeUpdate();        if(n>0) {            response.getWriter().println("Successfully Uploaded!");        }        }catch(Exception e) {System.out.println("Image E: "+e);}    }}Type Exception ReportMessage WS_Logo-02 (1).jpg (The system cannot find the file specified)Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Answer 1

request.getParameter() 方法将返回字符串，但要获取实际图像，您需要获取文件部分输入流。然后通过使用该部分，您可以在服务器上创建图像，并进一步将其作为二进制文件存储在数据库中。最有效的方法是将所有文件存储在外部存储（如 S3 存储桶）中，并将路径存储在数据库中。你可以试试下面的代码。

package com.imageUpload.controller;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.sql.Connection;

import java.sql.PreparedStatement;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.imageUpload.utill.DbConnection;

@WebServlet("/ImageUpload")

@MultipartConfig

public class ImageUpload extends HttpServlet {

    private static final long serialVersionUID = 1L;

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

        String name=request.getParameter("name");

        InputStream uploadedInputStream = null;

        Part filePart = null;

        String image = "";

        filePart = request.getPart("image"); // Retrieves <input type="file" name="image">

            if (filePart != null) {

                image = Paths.get(filePart.getSubmittedFileName()).getFileName().toString(); //image->name

                uploadedInputStream = filePart.getInputStream();

            }

        FileInputStream fis=new FileInputStream(new File(image));

        Connection con=DbConnection.getConnection();

        try {   

        PreparedStatement ps=con.prepareStatement

            ("insert into image(name,image)values(?,?)");

        ps.setString(1,name);

        ps.setBinaryStream(3, fis);

        int n = ps.executeUpdate();

        if(n>0) {

            response.getWriter().println("Successfully Uploaded!");

        }

        }catch(Exception e) {System.out.println("Image E: "+e);}

    }

}