Servlet-文件上传@MultipartConfig，Part

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Servlet-文件上传@MultipartConfig，Part

sf2gis@163.com

2015年9月18日

1 目标：后台获取客户端上传文件内容并保存。

2 原理：前端使用文件标签将内容以二进制的形式传给容器。后端使用servlet的@MultipartConfig 标记servlet解析文件读取part。

3 流程：前端使用文件标签，后端读取part。

4 方法：前端上传文件，后端直接读取part。

参考：http://blog.csdn.net/xiazdong/article/details/7208316

4.1 前端上传文件：<inputtype=“file”>标签。

设置请求方式：method=”post”

设置编码类型：enctype=”multipart/form-data”

指定servlet：action=” /testAMap/ts"。

示例：

<formmethod="post" enctype="multipart/form-data"action="/testAMap/ts">

<button type="submit"> submit</button>

</form>

4.2 后端读取文件：使用@MultipartConfig标记Servlet，读取part内容。

创建处理文件Servlet：使用@MultipartConfig标记。

处理part内容：读取文件名getSubmittedFileName（），文件大小getSize()，保存write()。

Part part=request.getPart("file");

pw.println("name="+part.getHeader("content-dispostion"));

byte[] buff=new byte[(int) part.getSize()];

part.getInputStream().read(buff);

5 示例

5.1 保存上传的文件到服务器指定目录

//后台文件处理Servlet：UploadFile.java

package lee;

import java.io.IOException;

importjavax.servlet.ServletException;

importjavax.servlet.annotation.MultipartConfig;

importjavax.servlet.annotation.WebServlet;

importjavax.servlet.http.HttpServlet;

importjavax.servlet.http.HttpServletRequest;

importjavax.servlet.http.HttpServletResponse;

importjavax.servlet.http.Part;

/**

* Servlet implementation class UploadFile

@WebServlet("/UploadFile")

@MultipartConfig

public class UploadFileextends HttpServlet {

private static final long serialVersionUID = 1L;

/**

* @see HttpServlet#HttpServlet()

public UploadFile() {

super();

// TODO Auto-generated constructor stub

}

/**

* @seeHttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

response.getWriter().append("Served at:").append(request.getContextPath());

Part p=request.getPart("clientf");

StringfileName=p.getSubmittedFileName();

System.out.println("name="+fileName);

System.out.println("size="+p.getSize());

StringfilePath=getServletContext().getRealPath("/uploadfiles");

System.out.println(filePath);

p.write(filePath+"/"+fileName);

}

/**

* @seeHttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

doGet(request, response);

}

//前台文件上传页面：a.jsp

<%@ pagelanguage="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"session="false"%>

<!DOCTYPE html PUBLIC"-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<metahttp-equiv="Content-Type" content="text/html;charset=UTF-8">

<title>Insert titlehere</title>

</head>

<body>

this is a.jsp

<%="aync return="+new java.util.Date() %>

<%=request.getAttribute("async") %>

<formmethod="post" enctype="multipart/form-data"action="UploadFile">

<inputtype="file" name="clientf"/>

<buttontype="submit"> submit</button>

</form>

</body>

</html>

//结果

5.2 显示上传的文件内容

//upload.htm

<!DOCTYPE HTML PUBLIC"-//W3C//DTD HTML 4.0 Transitional//EN">

<html>

<head>

<title>Untitled</title>

</head>

<body>

Hello World!

<inputtype="file" name="file"/>

<buttontype="submit"> submit</button>

</form>

</body>

</html>

//web.xml

<?xmlversion="1.0" encoding="UTF-8"?>

<web-appversion="3.0"

xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"

metadata-complete="false">

Servlet and JSP Examples.

</description>

<display-name>Servlet and JSPExamples</display-name>

</web-app>

//TestServlet.java

package com.thbd;

import java.io.IOException;

import java.io.PrintWriter;

importjavax.servlet.ServletException;

importjavax.servlet.annotation.MultipartConfig;

importjavax.servlet.annotation.WebServlet;

importjavax.servlet.http.HttpServlet;

importjavax.servlet.http.HttpServletRequest;

importjavax.servlet.http.HttpServletResponse;

importjavax.servlet.http.Part;

/**

* Servlet implementation class TestServlet

@WebServlet(urlPatterns="/ts")

@MultipartConfig

public class TestServletextends HttpServlet {

private static final long serialVersionUID = 1L;

/**

* Default constructor.

public TestServlet() {

// TODO Auto-generated constructor stub

}

/**

* @seeHttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

response.setContentType("text/html");

PrintWriter pw=response.getWriter();

pw.println("<h1>Hello,I amServlet.</h1>");

Partpart=request.getPart("file");

pw.println("name="+part.getHeader("content-dispostion"));

byte[] buff=newbyte[(int) part.getSize()];

part.getInputStream().read(buff);

pw.println(part.getSize()+new String(buff));

}

/**

* @seeHttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

doGet(request,response);

}

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