上传一个文件在一个servlet中 [英] upload a file in a servlet

问题描述

我需要在我的服务器上存储 cad 文件，但是我无法使上传工作。我试图让这个工作几个小时，但我不能。 Atm我有这个。
这给了我一个错误，即

随机数 .temp不存在（java.io .FileNotFoundException：/home/nick/.netbeans/7.1.2/config/GF3_1/domain1/generated/jsp/lrt/upload_700679fb_13a96c78523__7ffb_00000006.tmp（没有这样的文件或目录）

 包管理员; 
 
导入java.io.IOexception; 
导入java.io.InputStream; 
进口的java.io.PrintWriter; 
进口java.util.Collection中; 
进口javax.servlet.ServletException; 
进口javax.servlet.annotation.MultipartConfig; 
进口的javax。 servlet.annotation.WebServlet; 
进口javax.servlet.http.HttpServlet; 
进口javax.servlet.http.HttpServletRequest; 
进口javax.servlet.http.HttpServletResponse; 
进口javax.servlet.http.Part; 
 
 @WebServlet（名称= UploadServlet，URL模式= { / UploadServlet}）
 @MultipartConfig 
公共类UploadServlet延伸的HttpServlet { 
 
 @Override 
保护的vo id doPost（HttpServletRequest请求，
 HttpServletResponse responst）抛出ServletException，IOException {
 Collection< Part> parts = request.getParts（）; 
 if（parts.size（）！= 3）{
 //可以写错误页面，表示所有的细节都没有输入
} 
 Part filePart = request.getPart（cad ）; 
 InputStream sInputStream = filePart.getInputStream（）; 
 //读取imageInputStream 
 filePart.write（filePart.getName（））; 
 //读取名称，字符串类型
部分namePart = request.getPart（cad）; 
 if（namePart.getSize（）> 20）{
 //写入名称不能超过20个字符
} 
 //使用nameInputStream（如果需要的话）
 InputStream nameInputStream = namePart.getInputStream（）; 
 // name，字符串类型也可以使用Request参数获得
 String nameParameter = request.getParameter（name）; 
 //同样可以读取年龄属性
 Part agePart = request.getPart（age）; 
 int ageParameter = Integer.parseInt（request.getParameter（age））; 
 
 $ b @覆盖
 public String getServletInfo（）{
 return简短描述; 
 
 
 $ / code $ / pre 
 
解决方案
表示上传文件的临时文件无法找到。
 
 
 
该路径表示存储在Netbeans项目文件夹中的Glassfish工作文件夹中。也许Netbeans内部正在进行一些积极的清理/ hotdeploy，临时文件已经过早地被扫描了？或者也许只有不足的写权利？这取决于抛出异常的方式和位置的上下文 - —这是不明确的你的问题。
 
 
 
首先，我建议告诉 @MultipartConfig 来存储临时文件在一个不同的，有点更永久和可写，地点。例如，
 
 
  @MultipartConfig（location =/ var / webapp / temp）
  
 
I need to store cad files on my server, but I can't get the upload to work. I tried to get this working for hours but I just can't. Atm I have this. 
This gives me an error that 

random number.temp doesn't exist ( java.io.FileNotFoundException: /home/nick/.netbeans/7.1.2/config/GF3_1/domain1/generated/jsp/lrt/upload_700679fb_13a96c78523__7ffb_00000006.tmp (No such file or directory )
package Admin;

import java.io.IOexception;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Collection;
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;

@WebServlet(name = "UploadServlet", urlPatterns = {"/UploadServlet"})
@MultipartConfig
public class UploadServlet extends HttpServlet {

    @Override
     protected void doPost(HttpServletRequest request, 
       HttpServletResponse responst) throws ServletException, IOException {
      Collection<Part> parts = request.getParts();
      if (parts.size() != 3) {
         //can write error page saying all details are not entered
      }
       Part filePart = request.getPart("cad");
       InputStream sInputStream = filePart.getInputStream();
       //read imageInputStream
       filePart.write(filePart.getName());
       //Read Name, String Type 
       Part namePart = request.getPart("cad");
       if(namePart.getSize() > 20){
           //write name cannot exceed 20 chars
       }
       //use nameInputStream if required        
       InputStream nameInputStream = namePart.getInputStream();
       //name , String type can also obtained using Request parameter 
       String nameParameter = request.getParameter("name");
       //Similarly can read age properties
       Part agePart = request.getPart("age");
       int ageParameter = Integer.parseInt(request.getParameter("age"));
    }

    @Override
    public String getServletInfo() {
        return "Short description";
    }
}

解决方案
The temporary file representing the uploaded file could not be found.

The path indicates that it's stored in Glassfish work folder in Netbeans project folder. Perhaps there's some agressive cleanup/hotdeploy going on inside Netbeans and the temporary file was been swept too soon? Or perhaps there are just insufficient write rights? That depends on the context of how and where the exception is been thrown — which isn't clear from your question.

To start, I'd suggest telling @MultipartConfig to store the temp files in a different, a bit more permanent and writable, location. For example,
@MultipartConfig(location="/var/webapp/temp")


                        
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