zbb20180613 Spring MVC实现大文件下载功能

Spring MVC实现大文件下载功能

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

<modelVersion>4.0.0</modelVersion>

<groupId>com.zbb</groupId>

<artifactId>TestUploadFile</artifactId>

<packaging>war</packaging>

<version>0.0.1-SNAPSHOT</version>

<name>TestUploadFile Maven Webapp</name>

<url>http://maven.apache.org</url>

<dependencies>

<dependency>

<groupId>junit</groupId>

<artifactId>junit</artifactId>

<version>3.8.1</version>

<scope>test</scope>

</dependency>

<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->

<dependency>

<groupId>javax.servlet</groupId>

<artifactId>javax.servlet-api</artifactId>

<version>4.0.0</version>

<scope>provided</scope>

</dependency>

<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->

<dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-webmvc</artifactId>

<version>4.3.17.RELEASE</version>

</dependency>

 

 

</dependencies>

<build>

<finalName>TestUploadFile</finalName>

<plugins>

<plugin>

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-compiler-plugin</artifactId>

<configuration>

<source>1.8</source>

<target>1.8</target>

</configuration>

</plugin>

</plugins>

</build>

</project>

 

web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"

version="3.1">

 

<!-- *** 初始化Spring容器开始 *** -->

<listener>

<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

</listener>

<context-param>

<param-name>contextConfigLocation</param-name>

<param-value>classpath:spring.xml</param-value>

</context-param>

<!-- === 初始化Spring容器结束 === -->

 

<!-- *** 初始化SpringMVC开始 *** -->

<servlet>

<servlet-name>springMVC</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<init-param>

<param-name>contextConfigLocation</param-name>

<param-value>classpath:spring-mvc.xml</param-value>

</init-param>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>springMVC</servlet-name>

<url-pattern>/</url-pattern>

</servlet-mapping>

<!-- === 初始化SpringMVC结束 === -->

</web-app>

spring.xml

<?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:p="http://www.springframework.org/schema/p"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"

xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context.xsd

http://www.springframework.org/schema/aop

http://www.springframework.org/schema/aop/spring-aop.xsd

http://www.springframework.org/schema/tx

http://www.springframework.org/schema/tx/spring-tx.xsd">

 

 

<context:component-scan base-package="com.zbb" />

</beans>

spring-mvc.xml

<?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:p="http://www.springframework.org/schema/p"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"

xmlns:mvc="http://www.springframework.org/schema/mvc"

xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context.xsd

http://www.springframework.org/schema/aop

http://www.springframework.org/schema/aop/spring-aop.xsd

http://www.springframework.org/schema/tx

http://www.springframework.org/schema/tx/spring-tx.xsd

http://www.springframework.org/schema/mvc

http://www.springframework.org/schema/mvc/spring-mvc.xsd">

 

<mvc:annotation-driven />

 

<mvc:default-servlet-handler />

 

<bean

class="org.springframework.web.servlet.view.InternalResourceViewResolver">

<property name="viewClass"

value="org.springframework.web.servlet.view.JstlView" />

<property name="prefix" value="/WEB-INF/jsp/" />

<property name="suffix" value=".jsp" />

</bean>

 

<!--只扫描@Controller注解类,否则影响事务 -->

<context:component-scan base-package="com.zbb"

use-default-filters="false">

<context:include-filter type="annotation"

expression="org.springframework.stereotype.Controller" />

</context:component-scan>

</beans>

 

 

TestDownLoadFileController .java

package com.zbb.controller;

 

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.PrintWriter;

 

import javax.servlet.http.HttpServletResponse;

 

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

 

@Controller

@RequestMapping("/uploadFile")

public class TestDownLoadFileController {

@RequestMapping("/download")

public void downloadNet(HttpServletResponse response) throws Exception {

try {

String path = "E:\BaiduYunDownload\黑马程序员视频.z03";

File file = new File(path);

if (file.exists()) {

String filename = file.getName();

InputStream fis = new BufferedInputStream(new FileInputStream(file));

response.reset();

response.setContentType("application/x-download");

response.addHeader("Content-Disposition",

"attachment;filename=" + new String(filename.getBytes(), "UTF-8"));

response.addHeader("Content-Length", "" + file.length());

OutputStream out = new BufferedOutputStream(response.getOutputStream());

response.setContentType("application/octet-stream");

 

byte[] buffer = new byte[1024 * 1024 * 10];

int i = -1;

while ((i = fis.read(buffer)) != -1) {

out.write(buffer, 0, i);

 

}

fis.close();

out.flush();

out.close();

try {

response.wait();

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

} else {

PrintWriter out = response.getWriter();

out.print("<script>");

out.print("alert("not find the file")");

out.print("</script>");

}

} catch (IOException ex) {

PrintWriter out = response.getWriter();

out.print("<script>");

out.print("alert("not find the file")");

out.print("</script>");

}

}

}

 

 

实现文件下载主要主要步骤如下

• 创建文件对象：File file = new File(path);
• 利用BufferedInputStream从文件流读取数据：这里选用BufferedInputStream而不是InputStream，是因为在读取大文件时，BufferedInputStream的速度快上很多；
• 设置reponsed对象，响应客户端的请求，即下载文件。
• 这里需要注意的是，由于一般的视频文件都是G级别的，若一次性从文件流读取数据如：

byte[] buffer = new byte[fis. available()]

会导致内存溢出，所以不能一次性读取，应每次读取一部分，如每次读取10M：

     byte[] buffer = new byte[1024 * 1024 * 10];

•  接下去就是响应客户端的请求了，这里就不用多说了吧。

  在jsp页面只需设置一个链接指向该action即可

      <a href="/download" >下载</a>

  页面点击链接即可下载该视频：