springMVC实现文件上传和下载

程序员文章站 2022-07-05 22:09:08

本文实例为大家分享了springmvc实现文件上传和下载的具体代码，供大家参考，具体内容如下1准备工作web.xml文件导入dispatcherservlet，characterencodingfil...

本文实例为大家分享了springmvc实现文件上传和下载的具体代码，供大家参考，具体内容如下

1准备工作

web.xml文件导入dispatcherservlet，characterencodingfilter

<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>


    <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.characterencodingfilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
</filter-mapping>

前端测试页面

<%@ page contenttype="text/html;charset=utf-8" language="java" %>
<html>
  <head>
    <title>$title$</title>
  </head>
  <body>
  <%--  必须将表单的method设置为post--%>
  <%--  设置enctype属性为multipart/form-data，二进制传递数据--%>
  <form action="${pagecontext.request.contextpath}/upload2" enctype="multipart/form-data" method="post">
    <input type="file" name="file"/>
    <input type="submit" value="upload">
  </form>
  <br/>
  <a href="${pagecontext.request.contextpath}/download" rel="external nofollow" >点击下载</a>
  </body>
</html>

spring配置文件applicationcontext.xml

<?xml version="1.0" encoding="utf8"?>
<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">

    <!-- 自动扫描指定的包，下面所有注解类交给ioc容器管理，根据自己的项目扫描包 -->
    <context:component-scan base-package="com.zky.controller"/>
    <!-- 注解驱动 -->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.stringhttpmessageconverter">
                <constructor-arg value="utf-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.mappingjackson2httpmessageconverter">
                <property name="objectmapper">
                    <bean class="org.springframework.http.converter.json.jackson2objectmapperfactorybean">
                        <property name="failonemptybeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>
    <!-- 静态资源过滤-->
    <mvc:default-servlet-handler/>
    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.internalresourceviewresolver"
          id="internalresourceviewresolver">
        <!-- 前缀 -->
        <property name="prefix" value="/web-inf/jsp/" />
        <!-- 后缀 -->
        <property name="suffix" value=".jsp" />
    </bean>

    <!--文件上传配置-->
    <bean id="multipartresolver"  class="org.springframework.web.multipart.commons.commonsmultipartresolver">
        <!-- 请求的编码格式，必须和jsp的pageencoding属性一致，以便正确读取表单的内容，默认为iso-8859-1 -->
        <property name="defaultencoding" value="utf-8"/>
        <!-- 上传文件大小上限，单位为字节（10485760=10m） -->
        <property name="maxuploadsize" value="10485760"/>
        <property name="maxinmemorysize" value="40960"/>
    </bean>
</beans>

2.文件上传

controller

package com.zky.controller;

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;

import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import java.io.*;
import java.net.urlencoder;

@controller
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commonsmultipartfile则为数组即可
    @requestmapping("/upload")
    public string fileupload(@requestparam("file") commonsmultipartfile file , httpservletrequest request) throws ioexception {

        //获取文件名 : file.getoriginalfilename();
        string uploadfilename = file.getoriginalfilename();

        //如果文件名为空，直接回到首页！
        if ("".equals(uploadfilename)){
            return "redirect:/index.jsp";
        }
        system.out.println("上传文件名 : "+uploadfilename);

        //上传路径保存设置
        string path = request.getservletcontext().getrealpath("/upload");
        //如果路径不存在，创建一个
        file realpath = new file(path);
        if (!realpath.exists()){
            realpath.mkdir();
        }
        system.out.println("上传文件保存地址："+realpath);

        inputstream is = file.getinputstream(); //文件输入流
        outputstream os = new fileoutputstream(new file(realpath,uploadfilename)); //文件输出流

        //读取写出
        int len=0;
        byte[] buffer = new byte[1024];
        while ((len=is.read(buffer))!=-1){
            os.write(buffer,0,len);
            os.flush();
        }
        os.close();
        is.close();
        return "redirect:/index.jsp";
    }
}

采用file.transto 来保存上传的文件

/*
     * 采用file.transto 来保存上传的文件
     */
    @requestmapping("/upload2")
    public string  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()));

        return "redirect:/index.jsp";
    }

3.文件下载

@requestmapping(value="/download")
    public string downloads(httpservletresponse response , httpservletrequest request) throws exception{
        //要下载的图片地址，改为自己图片路径,我是下载在我的项目里面的
        string  path = request.getservletcontext().getrealpath("/upload");
        //文件名
        string  filename = "新建文本文档.txt";

        //1、设置response 响应头
        response.reset(); //设置页面不缓存,清空buffer
        response.setcharacterencoding("utf-8"); //字符编码
        response.setcontenttype("multipart/form-data"); //二进制传输数据
        //设置响应头
        response.setheader("content-disposition",
                "attachment;filename="+ urlencoder.encode(filename, "utf-8"));

        file file = new file(path,filename);
        //2、 读取文件--输入流
        inputstream input=new fileinputstream(file);
        //3、 写出文件--输出流
        outputstream out = response.getoutputstream();

        byte[] buff =new byte[1024];
        int index=0;
        //4、执行 写出操作
        while((index= input.read(buff))!= -1){
            out.write(buff, 0, index);
            out.flush();
        }
        out.close();
        input.close();
        return null;
    }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。

springMVC实现文件上传和下载

1准备工作

2.文件上传

3.文件下载

C#开发windows服务实现自动从FTP服务器下载文件

PHP设置图片文件上传大小的具体实现方法

使用AjaxFileUpload.js实现异步文件上传示例

Dynamics CRM 365中结合注释和WebApi实现图片上传

Python实现网站文件的全备份和差异备份

.Net Core实现图片文件上传下载功能

详解微信小程序文件下载--视频和图片

jQuery插件ImgAreaSelect实现头像上传预览和裁剪功能实例讲解一

C#下载歌词文件的同步和异步方法

asp.net实现服务器文件下载到本地的方法