文件上传与处理教程-优快云博客

本文链接：https://blog.youkuaiyun.com/fangguozi/article/details/17583739

1、upload.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form name="form1" action="<%=request.getContextPath() %>/uploadServlet" method="post" enctype="multipart/form-data">
文    件:<input type="file" name="file" /><br/>
文件描述：<input type="text" name="fileDesc" /><br/>
文件描述：<input type="text" name="fileDesc1" /><br/>
<input type="submit" value="开始上传" />
</form>
</body>
</html>

2、UploadServlet.java

package servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.List;

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

import org.apache.tomcat.util.http.fileupload.DiskFileUpload;
import org.apache.tomcat.util.http.fileupload.FileItem;
import org.apache.tomcat.util.http.fileupload.FileUploadException;

public class UploadServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setCharacterEncoding("UTF-8");	//设置编码方式
		response.getWriter().print("请使用post方式上传文件！");		//输出信息
	}
	
	@SuppressWarnings("unchecked")
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		File file = null;
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html; charset=utf-8");
		request.setCharacterEncoding("UTF-8");
		PrintWriter out = response.getWriter();
		DiskFileUpload diskFileUpload = new DiskFileUpload();
		try {
			List<FileItem> list = diskFileUpload.parseRequest(request);
			for(FileItem fileItem: list){
				if(fileItem.isFormField()){
					String fileDesc = new String(fileItem.getString().getBytes(),"UTF-8");
				}else{
					File remoteFile = new File(new String(fileItem.getName().getBytes(),"UTF-8"));
					file = new File(request.getContextPath()+"/attachment",remoteFile.getName());
					file.getParentFile().mkdirs();
					file.createNewFile();
					InputStream ins = fileItem.getInputStream();
					FileOutputStream ous = new FileOutputStream(file);
					
					byte[] buffer = new byte[1024];
					int len = 0;
					while((len = ins.read(buffer)) > -1){
						ous.write(buffer,0,len);
					}
					ous.close();
					ins.close();
				}
			}
			out.print("上传完毕！");
		} catch (FileUploadException e) {
			e.printStackTrace();
		}
	}
}

3、web.xml

<servlet>
  	<servlet-name>uploadServlet</servlet-name>
  	<servlet-class>servlet.UploadServlet</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>uploadServlet</servlet-name>
  	<url-pattern>/uploadServlet</url-pattern>
  </servlet-mapping>

注意：

A、上传文件时必须设置form的属性enctype为multipart/form-data，不然上传会不成功。

B、需要commons-fileupload.jar