SpringMVC框架实现图片上传与下载
程序员文章站
2023-11-27 14:40:16
本文实例为大家分享了springmvc框架实现图片上传与下载的具体代码，供大家参考，具体内容如下
1、新建一个maven webapp项目，引入需要用的夹包，pom.xm...
本文实例为大家分享了springmvc框架实现图片上传与下载的具体代码，供大家参考，具体内容如下
1、新建一个maven webapp项目，引入需要用的夹包，pom.xml文件的依赖包如下：
<dependencies> <!-- 用于生成图片的缩略图 --> <dependency> <groupid>net.coobird</groupid> <artifactid>thumbnailator</artifactid> <version>0.4.8</version> </dependency> <!-- 单元测试包 --> <dependency> <groupid>junit</groupid> <artifactid>junit</artifactid> <version>3.8.1</version> <scope>test</scope> </dependency> <!-- springmvc夹包 --> <dependency> <groupid>org.springframework</groupid> <artifactid>spring-webmvc</artifactid> <version>4.3.11.release</version> </dependency> <!-- spring核心包，用于依赖注入 --> <dependency> <groupid>org.springframework</groupid> <artifactid>spring-core</artifactid> <version>4.3.11.release</version> </dependency> <!-- servlet夹包 --> <dependency> <groupid>javax.servlet</groupid> <artifactid>javax.servlet-api</artifactid> <version>3.1.0</version> </dependency> <!-- javaee包，在jsp文件中使用--> <dependency> <groupid>javax</groupid> <artifactid>javaee-api</artifactid> <version>7.0</version> </dependency> <!-- 文件上传的夹包 ，用于文件上传--> <dependency> <groupid>commons-fileupload</groupid> <artifactid>commons-fileupload</artifactid> <version>1.3.1</version> </dependency> <!-- jstl标签包，在jsp中使用 --> <dependency> <groupid>javax.servlet</groupid> <artifactid>jstl</artifactid> <version>1.2</version> </dependency> </dependencies>
2、配置文件设置如下：
（1） web.xml内容为：
<?xml version="1.0" encoding="utf-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemalocation=" http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5"> <!-- 配置springmvc的前端控制器，可以配置多个前端控制器来拦截不同的url --> <servlet> <servlet-name>spring</servlet-name> <servlet-class>org.springframework.web.servlet.dispatcherservlet</servlet-class> <init-param> <param-name>contextconfiglocation</param-name> <param-value>classpath:springmvc.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>spring</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
（2）springmvc.xml文件内容为：
<?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/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd">
<!-- 配置jsp的视图解析器，可以配置多个viewresolver-->
<bean class="org.springframework.web.servlet.view.internalresourceviewresolver">
<!-- 会用到el表达式以及jstl的标签，必须包含这个类 -->
<property name="viewclass" value="org.springframework.web.servlet.view.jstlview"></property>
<property name="prefix" value="/" />
<property name="suffix" value=".jsp" />
</bean>
<!-- 1、自动注册defaultannotationhandlermapping ，annotationmethodhandleradapter，可以根据url映射到方法-->
<!-- 2、数据绑定，数字和日期的format，如@numberformat ,@dateformat,还有xml和json的默认读写功能 -->
<mvc:annotation-driven />
<!-- 1.加入对静态资源的处理 -->
<!-- 2.允许使用“/”做整体映射 -->
<mvc:default-servlet-handler/>
<!-- 自动扫描相关的包 -->
<context:component-scan base-package="thumbnail"/>
<!-- 对文件上传的处理，这里声明的id必须为multipartresolver-->
<bean id="multipartresolver" class="org.springframework.web.multipart.commons.commonsmultipartresolver" >
<!-- 最大为100m，单位为字节 -->
<property name="maxuploadsize" value="104857600"></property>
<property name="defaultencoding" value="utf-8"></property>
<property name="maxinmemorysize" value="40960"></property>
</bean>
</beans>
3、后端开发
（1） 控制器类：
@controller
@requestmapping("/")
public class imagecontroller {
//使用autowired时，该业务类需要声明为@service，此时xml中不用其它的配置
@autowired
private upload upload;
@autowired
private thumbnail thumbnail;
//文件上传并生成缩略图
@requestmapping(value="/thumb",method=requestmethod.post)
public string generateimage(@requestparam("image")commonsmultipartfile file,httpservletrequest request) throws ioexception
{
//根据相对路径获取绝对路径，图片上传后位于元数据中
string realuploadpath=request.getservletcontext().getrealpath("/")+"images";
//获取上传后原图的相对地址
string imageurl=upload.uploadimage(file, realuploadpath);
//获取生成的缩略图的相对地址
string thumbimageurl=thumbnail.generatethumbnail(file, realuploadpath);
return "redirect:/images";
}
//显示所有图片
@requestmapping(value="/images",method=requestmethod.get)
public modelandview showimages(httpservletrequest request,httpservletresponse response)
{
//根据相对路径获取绝对路径，图片上传后位于元数据中
list<string> rawimageslist=new arraylist<string>();
string realuploadpath=request.getservletcontext().getrealpath("/")+"images";
rawimageslist=imagelist.printfile(realuploadpath+"/rawimages");
modelandview mv=new modelandview();
mv.addobject("imagelist", rawimageslist);
mv.setviewname("images");
return mv;
}
//文件下载
@requestmapping("/download")
public void download(httpservletrequest request,httpservletresponse response) throws ioexception
{
string path=request.getservletcontext().getrealpath("/")+"/images/rawimages/";
string filename=request.getparameter("filename");
file file=new file(path+filename);
if(file.exists()){
//设置mime类型
response.setcontenttype("application/octet-stream");
//或者为response.setcontenttype("application/x-msdownload");
//设置头信息,设置文件下载时的默认文件名，同时解决中文名乱码问题
response.addheader("content-disposition", "attachment;filename="+new string(filename.getbytes(), "iso-8859-1"));
inputstream inputstream=new fileinputstream(file);
servletoutputstream outputstream=response.getoutputstream();
byte[] bs=new byte[1024];
while((inputstream.read(bs)>0)){
outputstream.write(bs);
}
outputstream.close();
inputstream.close();
}
}
}
（2）业务类：
@service
public class upload {
/*
* 上传图片并返回图片的相对地址
*/
public string uploadimage(commonsmultipartfile file,string realuploadpath) throws ioexception
{
//如果目录不存在则创建目录
file uploadfile=new file(realuploadpath+"/rawimages");
if(!uploadfile.exists()){
uploadfile.mkdirs();
}
//创建输入流
inputstream inputstream=file.getinputstream();
//生成输出地址url
string outputpath=realuploadpath+"/rawimages/"+file.getoriginalfilename();
//创建输出流
outputstream outputstream=new fileoutputstream(outputpath);
//设置缓冲区
byte[] buffer=new byte[1024];
//输入流读入缓冲区，输出流从缓冲区写出
while((inputstream.read(buffer))>0)
{
outputstream.write(buffer);
}
outputstream.close();
//返回原图上传后的相对地址
return "images/rawimages/"+file.getoriginalfilename();
}
}
@service
public class thumbnail {
//设置缩略图的宽度和高度
public static final int witdth=100;
public static final int heigth=100;
/*
* 生成缩略图并且返回相对地址
*/
public string generatethumbnail(commonsmultipartfile file,string realuploadpath) throws ioexception
{
//如果目录不存在则创建目录
file uploadfile=new file(realuploadpath+"/thumbimages");
if(!uploadfile.exists()){
uploadfile.mkdirs();
}
//缩略图保存的绝对地址
string des=realuploadpath+"/thumbimages/"+file.getoriginalfilename();
//生成缩略图
thumbnails.of(file.getinputstream()).size(witdth, heigth).tofile(des);
//返回缩略图的相对地址
return "images/thumbimages/"+file.getoriginalfilename();
}
}
public class imagelist {
//获取文件夹下所有文件名
public static list<string> printfile(string path) {
file file = new file(path);
list<string> images = new arraylist<string>();
// 是文件夹的话
if (file.isdirectory()) {
string[] filelist = file.list();
for (int i = 0; i < filelist.length; i++) {
file readfile = new file(path + "/" + filelist[i]);
if (!readfile.isdirectory()) {
images.add(readfile.getname());
}
}
}
return images;
}
}
4、前端开发
images.jsp的内容为：
<%@ page language="java" contenttype="text/html; charset=utf-8"
pageencoding="utf-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en" "http://www.w3.org/tr/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>上传图片</title>
</head>
<body>
<script type="text/javascript">
function validate()
{
var a=document.getelementbyid("file");
var form=document.getelementbyid("upload");
if(a.value==""){
alert("请先选择图片");
return false;
}
else{
form.submit();
}
}
</script>
<h1 align="center">图片上传与下载</h1>
<p>
<c:foreach var="image" items="${imagelist}">
<a href="images/rawimages/${image}" rel="external nofollow" target="_blank"><img src="images/thumbimages/${image}" /></a>
<a href="${pagecontext.request.contextpath}/download?filename=${image}" rel="external nofollow" >${image}</a>
</c:foreach>
</p>
<form id="upload" action="${pagecontext.request.contextpath}/thumb" method="post" enctype="multipart/form-data">
<input id="file" type="file" name="image" id="image" >
<input type="button" value="上传" οnclick="validate()">
</form>
</body>
</html>
5、文件结构
6、在tomcat上运行的最终成果：
url：http://localhost:8080/thumbnail/images
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。