简单的servlet下载

<servlet>
  <servlet-name>servletTest</servlet-name>
  <servlet-class>com.shangsheng.servlet.ServletTest</servlet-class>
</servlet>

<servlet-mapping>
  <servlet-name>servletTest</servlet-name>
  <url-pattern>*.do</url-pattern>
</servlet-mapping>

下载:<a href="a.do?name=timg.jpg">timg.jpg</a>

//文件的名字
String name = request.getParameter("name");
System.out.println("name:"+name);
File file =new File("E:\app\"+name);
FileInputStream fileInputStream =new FileInputStream(file);
byte[] bytes =new byte[fileInputStream.available()];
fileInputStream.read(bytes);
response.setCharacterEncoding("utf-8");
String filename= URLEncoder.encode(file.getName(),"utf-8");
response.setHeader("Content-Disposition","attachment; filename="+name);
ServletOutputStream out =response.getOutputStream();
out.write(bytes);
out.flush();
out.close();

maven配置：

<dependency>
  <groupId>commons-fileupload</groupId>
  <artifactId>commons-fileupload</artifactId>
  <version>1.3.3</version>
</dependency>
<dependency>
  <groupId>commons-io</groupId>
  <artifactId>commons-io</artifactId>
  <version>2.4</version>
</dependency>