SpringMVC 通过commons-fileupload实现文件上传

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">

    <!--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 id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--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 id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!--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>