SpringMVC-02 - 文件下载

浏览器默认按照inline方式处理访问资源  -- 浏览器可以打开就会直接打开，不能打开就下载。  

想要实现文件下载，首先需要导入相关jar包,上传与下载的jar包

 

1、修改响应头Context - Disposition 设置

     修改值为 "attachement;filename=文件名"

            // 设置响应头文件类型
		resp.setHeader("Content-Disposition", "attachment;filename="+fileName);

2、在JSP页面设置超链接指向请求资源

  

3、配置web.xml、springmvc.xml

// web.xml

<!-- 前端控制器 -->
	<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:springmvc.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>
	<!-- 过滤器 字符编码设置 -->
	<filter>
		<filter-name>encoding</filter-name>
		<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
		<init-param>
			<param-name>encoding</param-name>
			<param-value>utf-8</param-value>
		</init-param>
		<init-param>
			<param-name>forceEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>encoding</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

        // springmvc.xml
        <!-- 扫描注解 -->
		<context:component-scan base-package="com.yyl.controller"></context:component-scan>
		<!-- 注册驱动 -->
		<mvc:annotation-driven></mvc:annotation-driven>
		<!-- 静态资源 -->
		<mvc:resources location="/js/" mapping="/js/**"></mvc:resources>
		<mvc:resources location="/images/" mapping="/images/**"></mvc:resources>

4、编写controller类

    @RequestMapping("down")
	public void download(String fileName,HttpServletRequest req,HttpServletResponse resp) throws IOException{
		System.out.println("down page");
		// 设置响应头文件类型
		resp.setHeader("Content-Disposition", "attachment;filename="+fileName);
		// 将二进制流放入响应体
			// 获取输出流
		ServletOutputStream os = resp.getOutputStream();
			// 获取文件真实路径
		String path = req.getServletContext().getRealPath("files");
			//创建文件
		File file = new File(path,fileName);
			// 变为二进制流
		byte[] bs = FileUtils.readFileToByteArray(file);
			// 以流的形式输出
		os.write(bs);
		os.flush();
		os.close();
	}