SpringMVC 通过commons-fileupload实现文件上传

r囧r小猫 2021-09-21 16:01 274阅读 0赞

### 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">
        
        <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`id="multipartResolver"`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">
    
        
        <context:component-scan base-package="com.pro.controller"/>
        
        <mvc:default-servlet-handler/>
        
        <mvc:annotation-driven/>
    
        
        <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            
            <property name="prefix" value="/WEB-INF/jsp/"/>
            
            <property name="suffix" value=".jsp"/>
        </bean>
    
        
        <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            
            <property name="defaultEncoding" value="utf-8"/>
            
            <property name="maxUploadSize" value="10485760"/>
            <property name="maxInMemorySize" value="40960"/>
        </bean>
    </beans>

# 文件上传 Controller #

## 上传实现一 ##

## 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.mkdirs();
            }
    
            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

<dependencies>
        
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.3</version>
        </dependency>
        
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
        </dependency>
        
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
    </dependencies>