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    jiawei3998:SpringMVC 通过commons-fileupload实现文件上传

    作者:jiawei3998 时间:2021-01-31 16:24

    目录
    • 配置
      • web.xml
      • SpringMVC配置文件 applicationContext.xml
    • 文件上传 Controller
      • 上传实现一
      • 上传实现二
    • 测试
    • 依赖

    配置

    web.xml

    <?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_5_0.xsd"
             version="5.0">
        <!--注册DispatcherServlet-->
        <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:applicationContext.xml</param-value>
            </init-param>
            <load-on-startup>1</load-on-startup>
        </servlet>
        <servlet-mapping>
            <servlet-name>springmvc</servlet-name>
            <url-pattern>/</url-pattern>
        </servlet-mapping>
    </web-app>
    

    SpringMVC配置文件 applicationContext.xml

    上传文件的核心配置类:CommonsMultipartResolver,注意不要写错

    <?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">
    
        <!--配置自动扫描controller包-->
        <context:component-scan base-package="com.pro.controller"/>
        <!--配置静态资源过滤-->
        <mvc:default-servlet-handler/>
        <!--配置注解驱动-->
        <mvc:annotation-driven/>
    
        <!--配置视图解析器-->
        <bean  >
            <!--前缀-->
            <property name="prefix" value="/WEB-INF/jsp/"/>
            <!--后缀-->
            <property name="suffix" value=".jsp"/>
        </bean>
    
        <!--SpringMVC文件上传配置-->
        <bean  >
            <!--设置请求的编码格式, 必须和pageEncoding的属性一致, 以便正确读取表单的值, 默认为ISO-8859-1-->
            <property name="defaultEncoding" value="utf-8"/>
            <!--上传文件的大小限制, 单位为字节 (10485760 = 10M)-->
            <property name="maxUploadSize" value="10485760"/>
            <property name="maxInMemorySize" value="40960"/>
        </bean>
    </beans>
    


    文件上传 Controller

    上传实现一

    package com.pro.controller;
    
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.multipart.commons.CommonsMultipartFile;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.*;
    import java.net.URLEncoder;
    import java.util.HashMap;
    import java.util.Map;
    
    @RestController
    public class FileController {
        /*
         * 采用file.transferTo 来保存上传的文件
         */
        @RequestMapping("/upload2")
        public Map fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
    
            //上传路径保存设置
            String path = request.getServletContext().getRealPath("/upload");
            File realPath = new File(path);
            if (!realPath.exists()){
                realPath.mkdir();
            }
            //上传文件地址
            System.out.println("上传文件保存地址 --> "+realPath);
    
            //通过CommonsMultipartFile的方法直接写文件(注意这个时候)
            file.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));
    
            Map<Object, Object> hashMap = new HashMap<>();
            hashMap.put("code", 0);
            hashMap.put("msg", "上传成功");
    
            return hashMap;
        }
    }
    

    上传实现二

    这里的文件名称没有使用 UUID组合名称 为了方便测试

    package com.pro.controller;
    
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.multipart.commons.CommonsMultipartFile;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.*;
    import java.net.URLEncoder;
    import java.util.HashMap;
    import java.util.Map;
    
    @RestController
    public class FileController {
    
        // @RequestParam("file") 将 name=file 控件得到的文件封装成 CommonsMultipartFile 对象
        // 批量上传把 CommonsMultipartFile 改为数组即可
        @RequestMapping("/upload")
        public String upload(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
            // 获取文件名称
            String uploadFileName = file.getOriginalFilename();
    
            // 如果文件名为空, 直接返回首页
            if ("".equals(uploadFileName)) {
                return "file upload error";
            }
    
            System.out.println("上传文件名 --> " + uploadFileName);
    
    
            // 设置文件的保存位置
            String path = request.getServletContext().getRealPath("/upload");
            // 判断路径是否存在
            File realPath = new File(path);
            if (!realPath.exists()) {
                // 如果不存在就创建
                realPath.mkdir();
            }
    
            System.out.println("文件保存路径 --> " + realPath);
    
            // 获取文件输入流
            InputStream is = file.getInputStream();
            // 获取文件输出流
            FileOutputStream os = new FileOutputStream(new File(realPath, uploadFileName));
    
            // 缓冲区读写文件
            byte[] buffer = new byte[1024];
            int len;
            while ((len = is.read(buffer)) != -1) {
                os.write(buffer, 0, len);
                os.flush();
            }
    
            // 关闭流
            os.close();
            is.close();
    
            return "file upload success";
        }
    }
    

    测试

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
      <head>
        <title>$Title$</title>
      </head>
      <body>
        <form enctype="multipart/form-data" action="${pageContext.request.contextPath}/upload2" method="post">
          <input type="file" name="file">
          <input type="submit" value="上传实现一">
        </form>
        
        
        <form enctype="multipart/form-data" action="${pageContext.request.contextPath}/upload" method="post">
          <input type="file" name="file">
          <input type="submit" value="上传实现二">
        </form>
      </body>
    </html>
    

    依赖

    核心依赖就是 commons-fileupload

    <!--导入依赖-->
    <dependencies>
        <!--单元测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
        </dependency>
        <!--spring-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <!--文件上传-->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.3</version>
        </dependency>
        <!--servlet-api导入高版本的-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
        </dependency>
        <!--jsp-->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        <!--jstl表达式-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
    </dependencies>
    
    bk
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