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...................................... ..................................................... ..................................................... ........................ table

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 Report

Message 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.

Exception

java.io.FileNotFoundException: WS_Logo-02 (1).jpg (The system cannot find the file specified)
    java.io.FileInputStream.open0(Native Method)
    java.io.FileInputStream.open(FileInputStream.java:195)
    java.io.FileInputStream.<init>(FileInputStream.java:138)
    com.imageUpload.controller.ImageUpload.doPost(ImageUpload.java:27)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Answer 1

方法 request.getParameter() 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);}
    }
}