SpringMVC实现文件上传下载的全过程

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我是靠谱客的博主苹果歌曲，最近开发中收集的这篇文章主要介绍SpringMVC实现文件上传下载的全过程，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

前言

文件的上传和下载都是基于io复制,只不过

文件上传是浏览器向服务器发送报文

文件下载是服务器向浏览器发送报文

提示：以下是本篇文章正文内容，下面案例可供参考

一、通用配置

pom.xml

    <dependencies>
        <!-- SpringMVC -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.13</version>
        </dependency>

        <!-- 日志 -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>

        <!-- ServletAPI -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>

        <!-- Spring5和Thymeleaf整合包 -->
        <dependency>
            <groupId>org.thymeleaf</groupId>
            <artifactId>thymeleaf-spring5</artifactId>
            <version>3.0.12.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.1</version>
        </dependency>
<!--        springMVC end-->

        <!--    导入spring坐标-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.11</version>
        </dependency>
<!--        导入测试坐标-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <!--    测试坐标-->
<!--        导入集成测试坐标-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.3.13</version>
        </dependency>
        <!--        集成测试坐标end-->
        <!--        导入mysql坐标-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.24</version>
        </dependency>
        <!--        mysql坐标end-->
        <!--        导入druid连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.8</version>
        </dependency>
        <!--        导入druid连接池end-->
        <!--        导入spring上下文-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.11</version>
        </dependency>
        <!--        导入spring上下文end-->
<!--        导入spring web开发api start-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.3</version>
        </dependency>
        <!--        导入spring web开发end-->
<!--        导入jackson的依赖-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.12.1</version>
        </dependency>
        <!--上传功能的关键jar -->
        <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.1</version>
        </dependency>
    </dependencies>

上传功能的关键jar

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_4_0.xsd"
         version="4.0">
    <!--配置springMVC的编码过滤器-->
    <!--    SpringMVC中处理编码的过滤器一定要配置到其他过滤器之前，否则无效-->
    <!-- 字符集过滤器 -->
    <filter>
        <description>字符集过滤器</description>
        <filter-name>characterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <description>字符集编码</description>
            <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>

    <!-- 字符集拦截 -->
    <filter-mapping>
        <filter-name>characterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>


    <filter>
        <filter-name>HiddenHttpMethodFilter</filter-name>
        <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>HiddenHttpMethodFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <!--    注册前端控制器DispatcherServlet-->
    <servlet>
        <servlet-name>DispatcherServlet</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>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

springMVC.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:context="http://www.springframework.org/schema/context"
       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 https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--    扫描组件-->
    <context:component-scan base-package="com.vector"/>

    <!-- 配置Thymeleaf视图解析器 -->
    <bean id="viewResolver" class="org.thymeleaf.spring5.view.ThymeleafViewResolver">
        <property name="order" value="1"/>
        <property name="characterEncoding" value="UTF-8"/>
        <property name="templateEngine">

            <bean class="org.thymeleaf.spring5.SpringTemplateEngine">
                <property name="templateResolver">
                    <bean class="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver">

                        <!-- 视图前缀 -->
                        <property name="prefix" value="/WEB-INF/templates/"/>

                        <!-- 视图后缀 -->
                        <property name="suffix" value=".html"/>
                        <property name="templateMode" value="HTML5"/>
                        <property name="characterEncoding" value="UTF-8" />
                    </bean>
                </property>
            </bean>
        </property>
    </bean>

    <!-- 处理响应中文内容乱码 -->
    <bean class="org.springframework.http.converter.StringHttpMessageConverter">
        <property name="defaultCharset" value="UTF-8" />
        <property name="supportedMediaTypes">
            <list>
                <value>text/html</value>
                <value>application/json</value>
            </list>
        </property>
    </bean>

    <mvc:view-controller path="/" view-name="index"/>
    <mvc:view-controller path="/file" view-name="file"/>
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven/>

    <!--必须通过文件解析器的解析才能将文件转换为MultipartFile对象-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>
</beans>

实现页面跳转,vue文件解析,上传内容解析的关键

file.html内容demo

<body>
<a th:href="@{/testDown}" rel="external nofollow" >下载1.jpg</a>
<form th:action="@{/testUp}" method="post" enctype="multipart/form-data">
    头像: <input type="file" name="photo"><br>
    <input type="submit" value="上传">
</form>
</body>

二、实现文件下载,上传功能

package com.vector.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.UUID;

@Controller
public class FileUpAndDownController {

    @RequestMapping("/testDown")
    public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException {
        //获取ServletContext对象
        ServletContext servletContext = session.getServletContext();
        //获取服务器中文件的真实路径
        String realPath = servletContext.getRealPath("/static/img/1.jpg");
        //创建输入流
        InputStream is = new FileInputStream(realPath);
        //创建字节数组
        byte[] bytes = new byte[is.available()];
        //将流读到字节数组中
        is.read(bytes);
        //创建HttpHeaders对象设置响应头信息
        MultiValueMap<String, String> headers = new HttpHeaders();
        //设置要下载方式以及下载文件的名字
        //Content-Disposition 固定回复内容格式  attachment以附件形式下载  filename=1.jpg文件名
        //可以将filename拼接为动态命名
        headers.add("Content-Disposition", "attachment;filename=1.jpg");
        //设置响应状态码
        HttpStatus statusCode = HttpStatus.OK;
        //创建ResponseEntity对象
        ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers, statusCode);
        //关闭输入流
        is.close();
        return responseEntity;
    }
    @RequestMapping("/testUp")
    public String testUp(@Value("multipartResolver") MultipartFile photo,HttpSession session) throws IOException {
        //获取上传的文件的文件名
        String fileName = photo.getOriginalFilename();
        //处理文件重名问题
        //重名问题是java.io中写入同一文件默认覆盖原文件内容导致图片被覆盖.
        //获取文件名后缀
        String suffixName = fileName.substring(fileName.lastIndexOf("."));
        //将UUID作为文件名  uuid是32位随机数,几乎不可能会重复
        fileName = UUID.randomUUID().toString() + suffixName;
        //获取服务器中photo目录的路径
        ServletContext servletContext = session.getServletContext();
        String photoPath = servletContext.getRealPath("photo");
        File file = new File(photoPath);
        //判断服务器是否存在该路径
        if(!file.exists()){
            file.mkdir();
        }
        String finalPath = photoPath + File.separator + fileName;
        //实现上传功能
        photo.transferTo(new File(finalPath));
        return "success";
    }
}

下载功能测试