Java进阶：SpringMVC文件上传-CFANZ编程社区

1. 文件上传三要素

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

Java进阶：SpringMVC文件上传_文件上传

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"时候，form表单的正文内容格式是：key=value&key=value&key=value
enctype = "multipart/form-data"时候，请求正文内容就变成了多部份形式：

3. 单文件上传步骤

3.1 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>2.3</version>
</dependency>

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3.2 配置文件上传解析器

<!--配置文件上传解析器-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="defaultEncoding" value="UTF-8"/>
    <property name="maxUploadSize" value="500000"/>
</bean>

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3.3 编写文件上传代码

测试代码
注意：函数文件参数名必须与上传表单文件name一致
Java进阶：SpringMVC文件上传_表单_05

代码

① 获取上传文件的名称：getOriginalFilename()
String originalFilename = upload.getOriginalFilename();

② 设置存储路径：transferTo()
upload.transferTo(new File(“D:\upload” + originalFilename));

@RequestMapping(value = "/quick23")
@ResponseBody
public void save23(String username, MultipartFile upload) throws IOException {
System.out.println(12312312);
// 获得上传文件名称
String originalFilename = upload.getOriginalFilename();
// 设置存储路径
upload.transferTo(new File("D:\\upload\\" + originalFilename));
}

Java进阶：SpringMVC文件上传_表单_06

4. 多文件上传

与单文件上传类似，只需要多个参数即可

4.1 方式一

form表单name不一致，后端接口分别用不同参数进行接收

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<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/user/quick24" method="post" enctype="multipart/form-data">
    名称<label><input type="text" name="username"/></label><br>
    文件1<label><input type="file" name="upload"></label><br>
    文件2<label><input type="file" name="upload2"></label><br>
    <input type="submit" value="提交"><br>
</form>

</body>
</html>

@RequestMapping(value = "/quick24")
@ResponseBody
public void save24(String username, MultipartFile upload, MultipartFile upload2) throws IOException {
    System.out.println(upload);
    System.out.println(upload2);
    // 获得上传文件名称
    String originalFilename = upload.getOriginalFilename();
    // 设置存储路径
    upload.transferTo(new File("D:\\upload\\" + originalFilename));
    String originalFilename2 = upload2.getOriginalFilename();
    upload2.transferTo(new File("D:\\upload\\" + originalFilename2));
}

4.2 方式二

form表单name一直，后端接口用数组接收参数

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/user/quick25" method="post" enctype="multipart/form-data">
    名称<label><input type="text" name="username"/></label><br>
    文件1<label><input type="file" name="upload"></label><br>
    文件2<label><input type="file" name="upload"></label><br>
    <input type="submit" value="提交"><br>
</form>

</body>
</html>

@RequestMapping(value = "/quick25")
@ResponseBody
public void save25(String username, MultipartFile[] upload) throws IOException {
    for (MultipartFile multipartFile : upload) {
        String originalFilename = multipartFile.getOriginalFilename();
        multipartFile.transferTo(new File("D:\\upload\\" + originalFilename));
    }
}

Java进阶：SpringMVC文件上传_html_08