Servlet+Jsp实现图片或文件的上传功能

时间:2022-02-09 07:23:54

首先,我们创建一个新的web工程,在工程的WebRoot目录下新建一个upload文件夹,这样当我们将该工程部署到服务器上时,服务器便也生成个upload文件夹,用来存放上传的资源。

然后,在WebRoot目录下新建一个jsp文件,主要实现的作用就是选择上传的文件,提交至servlet来进行处理

详细代码如下:一个form将文件信息通过post方式传送到指定的servlet

<%@ page language="java" contentType="text/html; charset=GBK"
 pageEncoding="GBK"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title></title>
</head>
<body>
  <form action="UpLoad" method="post" enctype="multipart/form-data"> 
     请选择上传的图片或文件:<input type="file" name="fileName"/><input type="submit" value="上传"/> 
    </form> 
</body>
</html>

可以看到,我们将数据提交到工程下的upload/UpLoad。

之后,我们就来编写这个servlet——UpLoad.java

package ayds;

import java.io.File;
import java.io.IOException;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class UpLoad extends HttpServlet {

/**
  *
  */
 private static final long serialVersionUID = 1L;
 public void doGet(HttpServletRequest request, HttpServletResponse response)
 throws ServletException, IOException {
doPost(request, response);
}
 @SuppressWarnings("unchecked") 
    @Override 
   
//    protected void service(HttpServletRequest req, HttpServletResponse resp) 
//            throws ServletException, IOException { 
  public void doPost(HttpServletRequest req, HttpServletResponse resp)
 throws ServletException, IOException {
        req.setCharacterEncoding("GBK"); 
        resp.setContentType("text/html;charset=GBK"); 
        //为解析类提供配置信息 
        DiskFileItemFactory factory = new DiskFileItemFactory(); 
        //创建解析类的实例 
        ServletFileUpload sfu = new ServletFileUpload(factory); 
        //开始解析 
        sfu.setSizeMax(1024*400); 
        //每个表单域中数据会封装到一个对应的FileItem对象上 
        try { 
            List<FileItem> items = sfu.parseRequest(req); 
            //区分表单域 
            for (int i = 0; i < items.size(); i++) { 
                FileItem item = items.get(i); 
                //isFormField为true,表示这不是文件上传表单域 
                if(!item.isFormField()){ 
                    ServletContext sctx = getServletContext(); 
                    //获得存放文件的物理路径 
                    //upload下的某个文件夹   得到当前在线的用户  找到对应的文件夹 
                     
                    String path = sctx.getRealPath("/upload"); 
                    System.out.println("path=="+path); 
                    //获得文件名 
                    String fileName = item.getName(); 
                    System.out.println("fileName=="+fileName); 
                    //该方法在某些平台(操作系统),会返回路径+文件名 
//                    fileName = fileName.substring(fileName.lastIndexOf("/")+1);
                    fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
                    System.out.println("fileName=="+fileName);
                    File file = new File(path+"\\"+fileName); 
                    if(!file.exists()){ 
                        item.write(file); 
                        //将上传图片的名字记录到数据库中 
                     int j=Dao.insertImg(fileName, "无");
                          if(j==1){
                        resp.sendRedirect("index2.jsp");
                          }
                    } 
                } 
            } 
        } catch (Exception e) { 
            e.printStackTrace(); 
        } 
         
    }

}

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