http://www.codejava.net/frameworks/spring/spring-mvc-sample-application-for-downloading-files

n this article, we are going to show you how to implement file download functionality in a Spring MVC application. The solution is similar to the one described in the article: Send files from servlet to client for downloading, but is implemented in a Spring MVC application.

The following picture depicts workflow of the sample application we are going to build:

Project structure (Eclipse project):

The file to be downloaded in this application is SpringProject.zip file which resides in the downloads directory which is relative to the application’s directory.

1. Code of download page

Create index.jsp file under WebContent directory with the following HTML code:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Download Page</title>
</head>
<body>
    <center>
        <h2><a href="/download.do">Click here to download file</a></h2>
    </center>
</body>
</html>

This page simply shows a link “Click here to download file” with URL points to the relative path: download.do. We’ll configure Spring controller class to handle this URL.

2. Code of Spring controller class

Create FileDownloadController.java file under the source package net.codejava.spring with the following code:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
package net.codejava.spring;
 
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
 
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
 
@Controller
@RequestMapping("/download.do")
public class FileDownloadController {
     
    /**
     * Size of a byte buffer to read/write file
     */
    private static final int BUFFER_SIZE = 4096;
             
    /**
     * Path of the file to be downloaded, relative to application's directory
     */
    private String filePath = "/downloads/SpringProject.zip";
     
    /**
     * Method for handling file download request from client
     */
    @RequestMapping(method = RequestMethod.GET)
    public void doDownload(HttpServletRequest request,
            HttpServletResponse response) throws IOException {
 
        // get absolute path of the application
        ServletContext context = request.getServletContext();
        String appPath = context.getRealPath("");
        System.out.println("appPath = " + appPath);
 
        // construct the complete absolute path of the file
        String fullPath = appPath + filePath;      
        File downloadFile = new File(fullPath);
        FileInputStream inputStream = new FileInputStream(downloadFile);
         
        // get MIME type of the file
        String mimeType = context.getMimeType(fullPath);
        if (mimeType == null) {
            // set to binary type if MIME mapping not found
            mimeType = "application/octet-stream";
        }
        System.out.println("MIME type: " + mimeType);
 
        // set content attributes for the response
        response.setContentType(mimeType);
        response.setContentLength((int) downloadFile.length());
 
        // set headers for the response
        String headerKey = "Content-Disposition";
        String headerValue = String.format("attachment; filename=\"%s\"",
                downloadFile.getName());
        response.setHeader(headerKey, headerValue);
 
        // get output stream of the response
        OutputStream outStream = response.getOutputStream();
 
        byte[] buffer = new byte[BUFFER_SIZE];
        int bytesRead = -1;
 
        // write bytes read from the input stream into the output stream
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outStream.write(buffer, 0, bytesRead);
        }
 
        inputStream.close();
        outStream.close();
 
    }
}

This is a typical Spring controller class which is annotated by Spring MVC annotation types. The method doDownload() will receive requests from the client, read the file on server and send it to the client for downloading. Note that, unlike traditional Spring controller’s methods, the method doDownload()does not return a view name, because our purpose is to send a file to the client. The method exits as soon as the file is completely transferred to the client.

Recommended Book: Getting started with Spring Framework

3. Code of Spring configuration file

Create spring-mvc.xml file under WebContent\WEB-INF directory with the following content:

1
2
3
4
5
6
7
8
9
10
11
12
13
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">
 
    <context:component-scan base-package="net.codejava.spring" />
 
    <!-- your beans declaration goes here -->
</beans>

This is a deadly simple Spring configuration file which tells the framework to scan the package net.codejava.spring for annotated types (element <context:component-scan />). Of course your application will have some bean definitions, but for the purpose of this application, such configuration is enough to work.

Related Course: The Java Spring Tutorial

4. Code of web.xml

The Spring dispatcher servlet is configured to handle requests in the web.xml file as follows:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
        http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <display-name>FileDownloadSpringMVC</display-name>
    <servlet>
        <servlet-name>SpringController</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/spring-mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>SpringController</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>
</web-app>

Recommended Book: Spring in Action

5. Required jar files

Add the following jar files into the WebContent\WEB-INF\lib directory:

    1. commons-logging-1.1.1.jar
    2. spring-beans-3.2.1.RELEASE.jar
    3. spring-context-3.2.1.RELEASE.jar
    4. spring-core-3.2.1.RELEASE.jar
    5. spring-expression-3.2.1.RELEASE.jar
    6. spring-web-3.2.1.RELEASE.jar
    7. spring-webmvc-3.2.1.RELEASE.jar

The Commons Logging jar files can be downloaded from Apache Commons Logging, other jar files come from Spring framework 3.2.1 RELEASE download.

Related Course: The Java Spring Tutorial

6. Testing the application

Deploy the application on localhost Tomcat server, type the following URL into browser’s address bar:

http://localhost:8080/FileDownloadSpringMVC/

The download page is displayed:

Click on the link, the browser will ask to download the file:

You can download Eclipse project for this application as well as deployable WAR file in the attachment section below.

NOTES: One may ask why not just putting a file somewhere on the server and give the users a link to download it? Of course that will work, however that is a static way. By handling the file to be downloaded programmatically, we can obtain the following benefits:

    • Delivering the files dynamically, based on user’s requests.
    • Controlling access to the files: who can download and when the download is available.
    • Hiding the actual location of files on the server.

Recommended Book: Spring in Practice

[转] Spring MVC sample application for downloading files的更多相关文章

  1. 【spring mvc】application context的生命周期

    上一次讲application context中bean的生命周期,后面贴了一部分代码,但根本没理解代码意思,有幸在博客园看到一篇关于这部分的代码解析,特别长,特此做了一些整理笔记,并附上链接:htt ...

  2. 【spring mvc】application context中【bean】的生命周期

    生命周期过程 主要分为四部分: 一.实例化 1. 当调用者通过 getBean( name )向 容器寻找Bean 时,如果容器注册了org.springframework.beans.factory ...

  3. spring mvc 介绍

    Spring MVC Tutorial tag. * * If you do not want to deal with the intricities of the noscript * secti ...

  4. web框架的前生今世--从servlet到spring mvc到spring boot

    背景 上世纪90年代,随着Internet和浏览器的飞速发展,基于浏览器的B/S模式随之火爆发展起来.最初,用户使用浏览器向WEB服务器发送的请求都是请求静态的资源,比如html.css等.  但是可 ...

  5. Spring MVC Cookie example

    In this post we will see how to access and modify http cookies of a webpage in Spring MVC framework. ...

  6. Spring MVC Hello World Example(转)

    Spring 3 You may interest at this Spring 3 MVC hello world example. In Spring MVC web application, i ...

  7. spring mvc mybatis集成踩的坑

    开园这么多年了也没写几篇文章,现在想想光看别人的也不行啊,咱也自己写写,就写这天我我在做spring mvc与mybatis的集成时遇到的问题 1 spring与mybatis的集成 这个相信大家都弄 ...

  8. Inspection info: Checks Spring Boot application .properties configuration files. Highlights unresolved and deprecated configuration keys and in

    Cannot resolve class or package ‘jdbc’ less… (Ctrl+F1) Inspection info: Checks Spring Boot applicati ...

  9. ajax使用向Spring MVC发送JSON数据出现 org.springframework.web.HttpMediaTypeNotSupportedException: Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported错误

    ajax使用向Spring MVC发送JSON数据时,后端Controller在接受JSON数据时报org.springframework.web.HttpMediaTypeNotSupportedE ...

随机推荐

  1. GridView如何合并同类项

    /// <summary>     /// 合并GridView中某列相同信息的行(单元格)     /// </summary>     /// <param name ...

  2. supersr--打电话/短信分享/邮件分享

    //  Created by apple on 15/6/17. //  Copyright (c) 2015年 Super All rights reserved. // #import " ...

  3. 原始套接字SOCK_RAW

    原始套接字SOCK_RAW 实际上,我们常用的网络编程都是在应用层的报文的收发操作,也就是大多数程序员接触到的流式套接字(SOCK_STREAM)和数据包式套接字(SOCK_DGRAM).而这些数据包 ...

  4. 2.1顺序容器-vector

    vector 1) *   :使用vector必须包含vector头文件.可变长的动态数组,支持随机访问,所有STL算法都可以对vector进行操作. ** :随机根据下标访问某个元素的时间是一个常数 ...

  5. 用spring+hibernate+struts 项目记录以及常用的用法进等

    一.hibernate1. -----BaseDao------ // 容器注入 private SessionFactory sessionFactory; public void setSessi ...

  6. Android中shell命令语句

    最近学习了Android中碰到了shell命令,故收集终结了一下 Ccat zdd 浏览文件zdd的内容cat zdd1 zdd2 浏览多个文件的内容cat -n zdd浏览文件zdd的内容并显示行号 ...

  7. ViewPager部分源码分析一：加载数据

    onMeasure()调用populate(),完成首次数据初始化. populate()维护ViewPager的page,包括mItems和mAdapter. populate(): if (cur ...

  8. C#4.0图解教程 - 第24章 反射和特性 – 2.特性

    1.特性 定义 Attribute用来对类.属性.方法等标注额外的信息,贴一个标签(附着物) 通俗:给 类 或 类成员 贴一个标签,就像航空部为你的行李贴一个标签一样 注意,特性 是 类 和 类的成员 ...

  9. Ubuntu中给eclipse和android studio添加桌面快捷图标

    Ubuntu 12.04 创建应用程序启动项(可在Unity LaucherPad显示) http://www.cnblogs.com/bluestorm/archive/2012/10/12/272 ...

  10. Tiny Rss Reader - 迷你RSS阅读器

    发布新软件 TinyRss: Windows平台上的一个小巧的Rss阅读器. 用户界面: 项目地址: https://github.com/movsb/tinyrss.git 测试下载: http:/ ...