spring的文件上传和下载

web.xml的基本配置：

<?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_4_0.xsd"
         version="4.0">
    <listener>
            <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
        </listener>

        <context-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </context-param>

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

      <!--解决中文乱码-->
          <filter>
              <filter-name>CharacterEncodingFilter</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>
          </filter>
          <filter-mapping>
          <filter-name>CharacterEncodingFilter</filter-name>
          <url-pattern>/*</url-pattern>
          </filter-mapping>

</web-app>

 jsp页面如下代码 upload和download

upload：

<form action="upload.do" method="post" enctype="multipart/form-data">

  <%--用户名：<input name="username" > 密码：<input type="password" name="password">--%>
  文件 ：<input type="file" name="file">
  <%--<input type="button" value="注册" >--%>
  <button>提交</button>
</form>


download:
<a href="download.do?name=${path}">文件下载</a>

springMVC（springmvcxml）和spring(applicationContext.xml)的配置文件(spring的主配置文件不需要配置任何东西，这里我们只要创建就好了，不用管理):

<?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:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.aaa.springmvc.controller"></context:component-scan>
    <mvc:annotation-driven></mvc:annotation-driven>
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value=""></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
</beans>

控制器代码如下：

package com.aaa.springmvc.controller;

import com.aaa.spring.file.util.FileUtil;
import com.aaa.springmvc.entity.Users;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.UUID;

@Controller
public class UserControler {

    @RequestMapping("/upload")
    public String upload(Users users, MultipartFile file, Model model) {

        //真是文件名
        String trueName = file.getOriginalFilename();
        System.out.println(file.getName());
        //后缀名
        String suffix = trueName.substring(trueName.lastIndexOf("."));

        String path = "d:/img/";
　　　　　//使用UUID工具类为文件生成唯一文件名
        String savename = UUID.randomUUID().toString();
        File NewFile = new File(path + savename + suffix);
        try {
　　　　　　//写入文件的
            file.transferTo(NewFile);
        } catch (IOException e) {
            e.printStackTrace();
        }
        //存储value
        model.addAttribute("path", path + savename + suffix);
        return "login";
    }

    @RequestMapping("/download")
    public String download(String name, HttpServletResponse resp) {
        resp.setContentType("application/octet-stream");
        resp.setCharacterEncoding("UTF-8");
        //设置文件的名字
        resp.addHeader("Content-Disposition", "attachment; filename=" + name);
        InputStream is = null;
        OutputStream os = null;
        try {
            is = new FileInputStream(name);
            os = resp.getOutputStream();
            byte[] b = new byte[2048 * 10];
            int len = 0;
            while ((len = is.read(b)) != -1) {
                os.write(b, 0, len);
            }
            os.flush();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
　　　　　　　　//关闭文件流
            FileUtil.close(is, os);
        }


        return "success";
    }


    @RequestMapping("/login")
    public String login() {
        return "index";
    }
}