[刘阳Java]_SpringMVC文件上传第1季

今天来介绍一个关于SpringMVC框架的文件上传功能。首先我个人感觉SpringMVC框架的文件上传还是要比Struts2框架要好用一些，灵活性更强。因为SpringMVC框架的文件上传有几种不同的实现方式，所以我们先给大家介绍基于CommonsMultipartFile来实现文件上传的功能

1. 大家可以先了解案例实现的效果

2. 搭建一下文件上传必备的环境

导入commons-fileupload-13.2.jar，commons-io-2.5.jar
在SpringMVC的配置文件中增加支持文件上传的解析器，如果不加入文件上传的解析，那么我们提交的请求会出现HTTP 400的错误

3. 文件上传功能需求

客户端提交的上传文件需要保存到Web服务器指定的目录中
服务器保存的文件名字需要进行一定的修改

4. 功能实现步骤

添加支持文件上传的解析器

<?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:p="http://www.springframework.org/schema/p"

    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

        http://www.springframework.org/schema/context/spring-context.xsd

        http://www.springframework.org/schema/mvc

        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="com.gxa.springmvc.controller"></context:component-scan>

    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

        <property name="maxUploadSize" value="5242880"></property>

        <property name="maxInMemorySize" value="4096"></property>

        <property name="defaultEncoding" value="UTF-8"></property>

    </bean>

</beans>

编写文件上传的控制器代码

package com.gxa.springmvc.controller;

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.multipart.commons.CommonsMultipartFile;

/**

 * SpringMVC的文件上次应用

 * @author caleb

 *

 */

@Controller

@RequestMapping("/upload")

public class FileUploadController {

    /**

     * 单个文件上传

     * @throws IOException

     */

    @RequestMapping("/singlefileupload")

    public void singleFileUpload(@RequestParam(value="file") CommonsMultipartFile file, HttpServletRequest request, HttpServletResponse response) throws IOException {

        long start = System.currentTimeMillis();

        String uploadFileName = file.getOriginalFilename();

        String savePath = request.getServletContext().getRealPath("/") + "upload";

        savePath = savePath.replaceAll("\\\\", "/");

        String saveFileName = start + "" + uploadFileName.substring(uploadFileName.lastIndexOf("."));

        File dirs = new File(savePath);

        if (!dirs.exists()) {

            dirs.mkdirs();

        }

        file.transferTo(new File(dirs, saveFileName));

        long end = System.currentTimeMillis();

        response.setContentType("text/html;charset=UTF-8");

        PrintWriter out = response.getWriter();

        out.println("上传文件的名称 = " + uploadFileName);

        out.println("<p>");

        out.println("保存文件的路径 = " + savePath);

        out.println("<p>");

        out.println("保存文件的名称 = " + saveFileName);

        out.println("<p>");

        out.println("上传成功的时间 = " + String.valueOf(end - start) + "ms");

        out.flush();

        out.close();

    }

}

编写文件上传的html代码，注意表单中需要加入enctype="multipart/form-data"

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>Insert title here</title>

</head>

<body>

<form action="upload/singlefileupload.do" method="post" enctype="multipart/form-data">

<fieldset>

    <legend>单个文件上传</legend>

    <input type="file" name="file"><input type="submit">

</fieldset>

</form>

</body>

</html>

5. 控制器中代码解读

singleFileUpload中的@RequestParam("file") CommonsMultipartFile file

public void singleFileUpload(@RequestParam(value="file") CommonsMultipartFile file, HttpServletRequest request, HttpServletResponse response) throws IOException

注意：html代码中文件上传域中的name="file"要对应Java代码中@RequestParam("file") CommonsMultipartFile file

file.transferTo(new File(dirs, saveFileName)); 封装了解析文件上传的IO流，同时完成将文件保存到服务器的操作
因为在SpringMVC的配置文件中没有添加ViewResolver接口，所以我们就利用比较传统的Servlet API来展示上传成功的信息输出

源码下载地址：https://pan.baidu.com/s/1eSDZwFg

巴特西

[刘阳Java]_SpringMVC文件上传第1季_第10讲

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