Servlet 上传文件练习产生java.io.FileNotFoundException:错误路径正确

Question

问题遇到的现象和发生背景

java.io.FileNotFoundException:

问题相关代码，请勿粘贴截图

package com.unit8.servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.UUID;

import javax.servlet.ServletException;

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

@MultipartConfig //使得之前的Servlet 可以接收文件上传

public class Servlet8 extends HttpServlet{

public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html");
    response.setCharacterEncoding("GBK");
    request.setCharacterEncoding("GBK");
    PrintWriter out = response.getWriter();
    System.out.println("helloworld");
    out.print("测试一下");
    
    Part part = request.getPart("dddd");  //接收上传的文件
    
     String cd = part.getHeader("Content-Disposition");
    //截取不同类型的文件需要自行判断
     String filename = cd.substring(cd.lastIndexOf("."), cd.length());
     System.out.println("文件名:"+cd);
     System.out.println("后缀名:"+filename);
     String newFileName = UUID.randomUUID()+filename; //写入文件新的名字
     String serverPath=request.getServletContext().getRealPath("upload"); //获取服务器文件上传路径
     System.out.println("服务器upload路径:"+serverPath);
     File f1 =new File(serverPath+"\\"+newFileName);
     System.out.println(serverPath+"\\"+newFileName);
     FileOutputStream fos =new FileOutputStream(f1);//创建服务器文件写入对象--输出流
     InputStream is = part.getInputStream();//获取文件读取对象--输入流
     
     byte[] a = new byte[1024];//存放文件的byte数组
     int length =is.read(a);
     while(length!=-1){                    
        fos.write(a, 0, length);
        length =  is.read(a);
     }    
     out.print("文件写入成功");
     fos.close();
     is.close();
     

}
public void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException { 
    doGet(request,response);
    System.out.println("wahaha");
    response.setContentType("text/html");
//    PrintWriter out = response.getWriter();
    
}

public void init() throws ServletException {
    // Put your code here
}

}

运行结果及报错内容

我的解答思路和尝试过的方法

我想要达到的结果

Answer 1

文件不存在，需要先创建文件。