web文件上传与下载综合案例（数据库）

刺骨的言语ヽ痛彻心扉 2022-05-20 07:16 111阅读 0赞

>         之前发布了有关于文件上传和下载的一些知识，今天我结合数据库使用SpringMvc技术做了一个web版本的比较使用的上传与下载案例。步骤如下：
> 
> 一、准备环境
> 
> (1)创建一个web工程
> 
> (2)准备工程需要的jar包(在这里我多导入了一些，防止因为缺少jar包，出现错误)

![70][]

> (3)编写application.xml和springmvc.xml，代码如下：
> 
> application.xml:
> 
> <?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:mvc="http://www.springframework.org/schema/mvc"  
> xmlns:context="http://www.springframework.org/schema/context"  
> xmlns:aop="http://www.springframework.org/schema/aop"   
> xmlns:tx="http://www.springframework.org/schema/tx"  
> xsi:schemaLocation="http://www.springframework.org/schema/beans   
> http://www.springframework.org/schema/beans/spring-beans-3.2.xsd   
> http://www.springframework.org/schema/mvc   
> http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd   
> http://www.springframework.org/schema/context   
> http://www.springframework.org/schema/context/spring-context-3.2.xsd   
> http://www.springframework.org/schema/aop   
> http://www.springframework.org/schema/aop/spring-aop-3.2.xsd   
> http://www.springframework.org/schema/tx   
> http://www.springframework.org/schema/tx/spring-tx-3.2.xsd ">  
>   
>   
> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">  
> <property name="driverClassName" value="com.mysql.jdbc.Driver"/>  
> <property name="url" value="jdbc:mysql://localhost:3306/webuploadanddown?useUnicode=true&characterEncoding=utf8"/>  
> <property name="username" value="root"/>  
> <property name="password" value="410923"/>  
> </bean>  
>   
>   
> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  
> <property name="dataSource" ref="dataSource"/>   
> <property name="mapperLocations" value="classpath:com/nyist/cn/Dao/Impl/UpfileDao.xml"/>   
> </bean>  
>   
>   
> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">  
> <property name="sqlSessionFactory" ref="sqlSessionFactory"/>  
> <property name="basePackage" value="com.nyist.cn.Dao"/>  
> </bean>
> 
> </beans>
> 
>  
> 
> springmvc.xml:
> 
> <?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:mvc="http://www.springframework.org/schema/mvc"  
> xmlns:context="http://www.springframework.org/schema/context"  
> xmlns:aop="http://www.springframework.org/schema/aop"   
> xmlns:tx="http://www.springframework.org/schema/tx"  
> xsi:schemaLocation="http://www.springframework.org/schema/beans   
> http://www.springframework.org/schema/beans/spring-beans-3.2.xsd   
> http://www.springframework.org/schema/mvc   
> http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd   
> http://www.springframework.org/schema/context   
> http://www.springframework.org/schema/context/spring-context-3.2.xsd   
> http://www.springframework.org/schema/aop   
> http://www.springframework.org/schema/aop/spring-aop-3.2.xsd   
> http://www.springframework.org/schema/tx   
> http://www.springframework.org/schema/tx/spring-tx-3.2.xsd ">  
>   
>   
> <context:component-scan base-package="com.nyist.cn"></context:component-scan>  
>   
>   
> <mvc:annotation-driven></mvc:annotation-driven>  
>   
>   
>   
> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">  
> <property name="prefix" value="/WEB-INF/pages/"/>  
> <property name="suffix" value=".jsp"/>  
> </bean>  
>  
> 
> </beans>
> 
>  
> 
> (4)修改web.xml，配置控制器，加载以上两个配置文件，web.xml代码如下：
> 
> <?xml version="1.0" encoding="UTF-8"?>  
> <web-app version="3.0"   
> xmlns="http://java.sun.com/xml/ns/javaee"   
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   
> xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   
> http://java.sun.com/xml/ns/javaee/web-app\_3\_0.xsd">  
>   
>   
> <filter>  
> <filter-name>CharacterEncoding</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>CharacterEncoding</filter-name>  
> <url-pattern>/\*</url-pattern>  
> </filter-mapping>  
>   
>   
>   
> <listener>  
> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>  
> </listener>  
>   
>   
>    
>  <context-param>  
>   <param-name>contextConfigLocation</param-name>  
>   <param-value>classpath:application.xml</param-value>  
>  </context-param>  
>    
>    
>  <servlet>  
>   <servlet-name>UploadAndDownload</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>  
>  </servlet>  
>  <servlet-mapping>  
>   <servlet-name>UploadAndDownload</servlet-name>  
>   <url-pattern>\*.apex</url-pattern>  
>  </servlet-mapping>
> 
> </web-app>
> 
>  
> 
> (5)测试数据源能否获得
> 
> package com.nyist.cn.Test;  
>   
>   
> import org.junit.Test;  
> import org.springframework.context.support.ClassPathXmlApplicationContext;  
>   
>   
> public class TestDataSource \{  
>   
> @Test  
> public void test1()\{  
> ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("application.xml");  
> Object obj = context.getBean("sqlSessionFactory");  
> System.out.println("Connection:"+obj);  
> \}
> 
> \}
> 
>  
> 
> 运行结果：Connection:org.apache.ibatis.session.defaults.DefaultSqlSessionFactory@3349e9bb
> 
>  
> 
> 二、ORM映射
> 
> (1)第一步Object，建实体Upfile.java，代码如下：
> 
> package com.nyist.cn.model;  
>   
> //实体  
> public class Upfile \{  
> private String id; //文件ID  
> private String uuidname; //uuid文件名称  
> private String filename; //文件的真实名称  
> private String savepath; //文件的保存路径  
> private String uptime; //文件上传时间  
> private String description; //文件的描述  
> private String username; //上传的用户  
>   
> public String getDescription() \{  
> return description;  
> \}  
> public void setDescription(String description) \{  
> this.description = description;  
> \}  
> public String getId() \{  
> return id;  
> \}  
> public void setId(String id) \{  
> this.id = id;  
> \}  
> public String getUuidname() \{  
> return uuidname;  
> \}  
> public void setUuidname(String uuidname) \{  
> this.uuidname = uuidname;  
> \}  
> public String getFilename() \{  
> return filename;  
> \}  
> public void setFilename(String filename) \{  
> this.filename = filename;  
> \}  
> public String getSavepath() \{  
> return savepath;  
> \}  
> public void setSavepath(String savepath) \{  
> this.savepath = savepath;  
> \}  
> public String getUptime() \{  
> return uptime;  
> \}  
> public void setUptime(String uptime) \{  
> this.uptime = uptime;  
> \}  
> public String getUsername() \{  
> return username;  
> \}  
> public void setUsername(String username) \{  
> this.username = username;  
> \}  
> public Upfile() \{  
> super();  
> \}  
> public Upfile(String id, String uuidname, String filename, String savepath, String uptime,String description, String username) \{  
> super();  
> this.id = id;  
> this.uuidname = uuidname;  
> this.filename = filename;  
> this.savepath = savepath;  
> this.uptime = uptime;  
> this.description = description;  
> this.username = username;  
> \}  
> @Override  
> public String toString() \{  
> return "upfile \[id=" + id + ", uuidname=" + uuidname + ", filename=" + filename + ", savepath=" + savepath  
> \+ ", uptime=" + uptime + ",description="+description+", username=" + username + "\]";  
> \}  
> \}
> 
> (2)第二部R,Relational,即数据库的关系表
> 
> ①创建数据库
> 
>     //创建一个字符编码为UTF-8并且带有校对规则的数据库
> 
>     create database webUploadAndDownload character set utf8 collate utf8\_general\_ci;
> 
> ②创建数据表
> 
>     create table upfile(
> 
>         id varhcar(40) primary key,
> 
>         uuidname varchar(100) not null,
> 
>         filename varchar(100) not null,
> 
>         savepath varchar(255) not null,
> 
>         uptime datetime not null,
> 
>        description varchar(255),
> 
>        username varchar(40) not null
> 
>     );
> 
>  
> 
> (3)第三步M,Mapping映射，使用Mybatis 的配置文件将Java对象映射到数据库表中
> 
> 示例：
> 
> <insert id="addfile"  parameterType="com.nyist.cn.model.Upfile">  
> insert into upfile(id,uuidname,filename,savepath,uptime,description,username) values(\#\{id\},\#\{uuidname\},\#\{filename\},\#\{savepath\},\#\{uptime\},\#\{description\},\#\{username\})
> 
> </insert>
> 
>  
> 
> (4)编写Dao层，为了是数据库和程序持久化，我们在配置文件中创建了Bean工厂，在实现Dao接口时，我采用配置配置文件来实现Dao中的方法
> 
> UpfileDao.java 如下：
> 
> package com.nyist.cn.Dao;  
>   
>   
> import java.util.List;  
>   
>   
> import com.nyist.cn.model.Upfile;  
>   
>   
> public interface UpfileDao \{  
>   
> //添加文件  
> public void addfile(Upfile upfile);
> 
> \}
> 
>  
> 
> UpfileDaoImpl.xml如下：
> 
> <?xml version="1.0" encoding="UTF-8"?>  
> <!DOCTYPE mapper      
> PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"      
> "http://mybatis.org/dtd/mybatis-3-mapper.dtd">  
>   
>   
> <mapper namespace="com.nyist.cn.Dao.UpfileDao">  
> <insert id="addfile"  parameterType="com.nyist.cn.model.Upfile">  
> insert into upfile(id,uuidname,filename,savepath,uptime,description,username) values(\#\{id\},\#\{uuidname\},\#\{filename\},\#\{savepath\},\#\{uptime\},\#\{description\},\#\{username\})  
> </insert>  
>   
> <select id="getAllFile" resultType="com.nyist.cn.model.Upfile">  
> select \* from upfile order by uptime desc  
> </select>  
>   
> <select id="findUpfile" parameterType="java.lang.String" resultType="com.nyist.cn.model.Upfile">  
> select \* from upfile where id = \#\{id\}  
> </select>  
>   
> <delete id="deleteupfile" parameterType="java.lang.String">  
> delete from upfile where id = \#\{id\}  
> </delete>
> 
> </mapper>
> 
> (5)编写UpfileService接口和UpfileServiceImpl.java
> 
> UpfileService 接口如下：
> 
> package com.nyist.cn.Service;  
>   
>   
> import java.util.List;  
>   
>   
> import com.nyist.cn.model.Upfile;  
>   
>   
> public interface UpfileService \{  
> //添加文件  
> public void addfile(Upfile upfile);
> 
> \}
> 
> UpfileServiceImpl.java如下：
> 
> package com.nyist.cn.Service.Impl;  
>   
>   
> import java.util.List;  
>   
>   
> import org.springframework.beans.factory.annotation.Autowired;  
> import org.springframework.stereotype.Service;  
>   
>   
> import com.nyist.cn.Dao.UpfileDao;  
> import com.nyist.cn.Service.UpfileService;  
> import com.nyist.cn.model.Upfile;  
>   
>   
> @Service  
> public class UpfileServiceImpl implements UpfileService\{  
>   
>   
> @Autowired  
> private UpfileDao upfileDao ;  
>   
> @Override  
> public void addfile(Upfile upfile) \{  
> upfileDao.addfile(upfile);
> 
> \}
> 
> \}
> 
> (6)编写Controller
> 
> 代码如下:
> 
> package com.nyist.cn.Controller;  
>   
>   
> import java.io.File;  
> import java.io.FileInputStream;  
> import java.io.FileNotFoundException;  
> import java.io.IOException;  
> import java.io.OutputStream;  
> import java.lang.reflect.InvocationTargetException;  
> import java.net.URLEncoder;  
> import java.util.List;  
>   
>   
> import javax.servlet.ServletException;  
> import javax.servlet.http.HttpServletRequest;  
> import javax.servlet.http.HttpServletResponse;  
>   
>   
> import org.apache.commons.fileupload.servlet.ServletFileUpload;  
> import org.springframework.beans.factory.annotation.Autowired;  
> import org.springframework.stereotype.Controller;  
> import org.springframework.web.bind.annotation.RequestMapping;  
>   
>   
> import com.nyist.cn.Service.UpfileService;  
> import com.nyist.cn.Utils.WebUtils;  
> import com.nyist.cn.model.Upfile;  
> @Controller  
> public class UpfileController \{  
>   
> @Autowired  
> private UpfileService upfileService ;  
> /\*\*  
> \*  后台 jsp 页面访问  
> \* @return  
> \*/  
> @RequestMapping("index")  
> public String index()\{  
> return "index";  
> \}  
>   
> @RequestMapping("message")  
> public String message()\{  
> return "message";  
> \}  
>   
> @RequestMapping("head")  
> public String head()\{  
> return "head";  
> \}  
>   
> @RequestMapping("upload")  
> public String upload()\{  
> return "upload";  
> \}  
>   
> @RequestMapping("showdownload")  
> public String showdownload()\{  
> return "showdownload";  
> \}  
>   
>   
> @RequestMapping("UploadAction")  
> public void Upload(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException, IllegalAccessException, InvocationTargetException\{  
> //拿到前台传进来的数据   首先判断是否为mutipart/form-data提交方式  
> if(!ServletFileUpload.isMultipartContent(request))\{  
> request.setAttribute("message","上传的不是为有效的数据类型");  
> request.getRequestDispatcher("/message.apex").forward(request, response);  
> return ;  
> \}  
> //得到保存文件 的目录  
> String path = request.getSession().getServletContext().getRealPath("/WEB-INF/upload");  
> //制作WebUtils 工具类  封装request 和  savepath  
> Upfile upfile = WebUtils.doUpload(request,path);  
> upfileService.addfile(upfile);  
> System.out.println("Upfile:"+upfile);  
> request.setAttribute("message","上传成功！");  
> request.getRequestDispatcher("/message.apex").forward(request, response);  
> \}  
>   
> @RequestMapping("listfileAction")  
> public void listfile(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException\{  
> String method = request.getMethod();  
> if("GET".equals(method))\{  
> List<Upfile> list = upfileService.getAllFile();  
> request.setAttribute("list",list);  
> request.getRequestDispatcher("/showdownload.apex").forward(request, response);  
> return ;  
> \}  
> \}   
>   
> @RequestMapping("DownLoadAction")  
> public void DownLoad(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException\{  
> //拿到前台数据  
> String id = request.getParameter("id");  
> Upfile upfile = upfileService.findUpfile(id);  
> System.out.println("Upfile:"+upfile);  
> File file = new File(upfile.getSavepath()+File.separator+upfile.getUuidname());  
> System.out.println("File:"+file);  
> if(!file.exists())\{  
> request.setAttribute("message","下载资源已被删除");  
> request.getRequestDispatcher("/message.apex").forward(request, response);  
> return ;  
> \}  
> response.setHeader("content-disposition","attachment;filename="+URLEncoder.encode(upfile.getFilename(),"UTF-8"));  
> try \{  
> FileInputStream in = new FileInputStream(file);  
> OutputStream out = response.getOutputStream();  
> int len =0;  
> byte buffer\[\] = new byte\[1024\];  
> while((len = in.read(buffer))>0)\{  
> out.write(buffer, 0, len);  
> \}  
> in.close();  
> \} catch(FileNotFoundException e) \{  
> e.printStackTrace();  
> throw new RuntimeException(e);  
> \}  
> \}
> 
> \}
> 
>  
> 
> (7)测试运行结果如下
> 
> ![70 1][]

[70]: /images/20220520/f3727d43a9cf4b66ab0adbdf5f8e2fce.png
[70 1]: /images/20220520/ebf52040d4034d778ec4594a59403074.png