SpringMVC文件的上传

文件上传

1文件上传客户端三要素

• 表单项type=“file”
• 表单的提交方式是post
• 表单的enctype属性是多部分表单形式，及enctype=“multipart/form-data”

        <form action="${pageContext.request.contextPath}/user/quick19" method="post" enctype="multipart/form-data" >
            <input type="text" name="username"><br>
            <input type="file" name="uploadFile"><br>
            <input type="submit" value="提交">
        </form>

2文件上传原理

• 当form表单修改为多部分表单时，request.getParameter()将失效。
• enctype=“application/x-www-form-urlencoded”时，form表单的正文内容格式是：key=value&key=value&key=valu
• 当form表单的enctype取值为Mutilpart/form-data时，请求正文内容就变成多部分形式：
  

单文件上传实现

1.导入fileupload和io坐标
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.1</version>
        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.6</version>
        </dependency>
2.配置文件上传解析器
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
      	  <!--上传文件的编码类型-->
        <property name="defaultEncoding" value="UTF-8"></property>
          <!--上传文件总大小-->
        <property name="maxUploadSize" value="500000"></property>
    </bean>
3.编写文件上传代码
    @RequestMapping(value = "/quick19")
    @ResponseBody
    public void save19(String username, MultipartFile uploadFile) throws IOException {
 		System.out.println(username);
 		 //获得上传文件的名称
        String originalFilename = uploadFile.getOriginalFilename();
        uploadFile.transferTo(new File("D:\\upload\\"+originalFilename));
    }

多文件上传实现

<form action="${pageContext.request.contextPath}/user/quick20" method="post" enctype="multipart/form-data" >
    <input type="text" name="username"><br>
    <input type="file" name="uploadFile"><br>
    <input type="file" name="uploadFile"><br>
    <input type="file" name="uploadFile"><br>
    <input type="submit" value="提交">
</form>

    @RequestMapping(value = "/quick20")
    @ResponseBody
    public void save20(String username, MultipartFile[] uploadFile) throws IOException {
        System.out.println(username);
        for (MultipartFile multipartFile:uploadFile ){
            String originalFilename = multipartFile.getOriginalFilename();
            multipartFile.transferTo(new File("D:\\upload\\"+originalFilename));
        }
    }

本文地址：https://blog.csdn.net/weixin_46111703/article/details/107682876