基础框架 SpringMVC文件上传的三种方式

r囧r小猫 2023-01-01 10:58 150阅读 0赞

## 基础框架 SpringMVC文件上传的三种方式 ##

### 一、实现原理 ###

#### 1. 三种方式 ####

实现文件上传常用的三种方式：
    1.传统借助 三方组件Commons-fileupload 组件实现文件上传。自己从对象中获取解析。
    2.springmvc方式，减少了自己手动处理的工作。
    3.跨域服务器上传。

#### 前提条件 ####

A form 表单的 enctype 取值必须是： multipart/form-data
    (默认值是:application/x-www-form-urlencoded)
    enctype:是表单请求正文的类型
    B method 属性取值必须是 Post
    C 提供一个文件选择域<input type=”file” />

#### 2. 原理分析 ####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NTgzNjU1_size_16_color_FFFFFF_t_70]

### 二、案例验证 ###

1.  项目结构  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NTgzNjU1_size_16_color_FFFFFF_t_70 1]
2.  maven依赖

<?xml version="1.0" encoding="UTF-8"?>
    
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.hello</groupId>
        <artifactId>springmvc_fileupload</artifactId>
        <version>1.0-SNAPSHOT</version>
        <packaging>war</packaging>
    
        <name>springmvc_fileupload Maven Webapp</name>
        
        <url>http://www.example.com</url>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <maven.compiler.source>1.8</maven.compiler.source>
            <maven.compiler.target>1.8</maven.compiler.target>
            <spring.version>5.0.2.RELEASE</spring.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>${spring.version}</version>
            </dependency>
    
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-web</artifactId>
                <version>${spring.version}</version>
            </dependency>
    
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-webmvc</artifactId>
                <version>${spring.version}</version>
            </dependency>
    
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>servlet-api</artifactId>
                <version>2.5</version>
                <scope>provided</scope>
            </dependency>
    
            <dependency>
                <groupId>javax.servlet.jsp</groupId>
                <artifactId>jsp-api</artifactId>
                <version>2.0</version>
                <scope>provided</scope>
            </dependency>
    
            
            <dependency>
                <groupId>commons-fileupload</groupId>
                <artifactId>commons-fileupload</artifactId>
                <version>1.3.1</version>
            </dependency>
            <dependency>
                <groupId>commons-io</groupId>
                <artifactId>commons-io</artifactId>
                <version>2.4</version>
            </dependency>
    
            <dependency>
                <groupId>com.sun.jersey</groupId>
                <artifactId>jersey-core</artifactId>
                <version>1.18.1</version>
            </dependency>
            <dependency>
                <groupId>com.sun.jersey</groupId>
                <artifactId>jersey-client</artifactId>
                <version>1.18.1</version>
            </dependency>
    
        </dependencies>
    
        <build>
            <finalName>springmvc_day02_02_fileupload</finalName>
            <pluginManagement>
                <plugins>
                    <plugin>
                        <artifactId>maven-clean-plugin</artifactId>
                        <version>3.0.0</version>
                    </plugin>
                    
                    <plugin>
                        <artifactId>maven-resources-plugin</artifactId>
                        <version>3.0.2</version>
                    </plugin>
                    <plugin>
                        <artifactId>maven-compiler-plugin</artifactId>
                        <version>3.7.0</version>
                    </plugin>
                    <plugin>
                        <artifactId>maven-surefire-plugin</artifactId>
                        <version>2.20.1</version>
                    </plugin>
                    <plugin>
                        <artifactId>maven-war-plugin</artifactId>
                        <version>3.2.0</version>
                    </plugin>
                    <plugin>
                        <artifactId>maven-install-plugin</artifactId>
                        <version>2.5.2</version>
                    </plugin>
                    <plugin>
                        <artifactId>maven-deploy-plugin</artifactId>
                        <version>2.8.2</version>
                    </plugin>
                </plugins>
            </pluginManagement>
        </build>
    </project>

1.  web.xml

<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd" >
    
    <web-app>
      <display-name>Archetype Created Web Application</display-name>
    
      
      <filter>
        <filter-name>characterEncodingFilter</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>characterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
      </filter-mapping>
    
      
      <servlet>
        <servlet-name>dispatcherServlet</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>dispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
      </servlet-mapping>
    
    </web-app>

1.  springmvc.xml

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    
        
        <context:component-scan base-package="com.hello.controller"/>
    
        
        <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="prefix" value="/WEB-INF/pages/"/>
            <property name="suffix" value=".jsp"/>
        </bean>
    
        
        <mvc:resources location="/css/" mapping="/css/**"/>
        <mvc:resources location="/images/" mapping="/images/**"/>
        <mvc:resources location="/js/" mapping="/js/**"/>
    
        
        <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            <property name="maxUploadSize" value="10485760"/>
        </bean>
    
        
        <mvc:annotation-driven/>
    
    </beans>

1.  Controller

package com.hello.controller;
    
    import com.sun.jersey.api.client.Client;
    import com.sun.jersey.api.client.WebResource;
    import org.apache.commons.fileupload.FileItem;
    import org.apache.commons.fileupload.disk.DiskFileItemFactory;
    import org.apache.commons.fileupload.servlet.ServletFileUpload;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.multipart.MultipartFile;
    
    import javax.servlet.http.HttpServletRequest;
    import java.io.File;
    import java.util.List;
    import java.util.UUID;
    
    /** * 文件上传控制器 * * @author zrj * @date 2021/1/2 * @since V1.0 **/
    @Controller
    @RequestMapping("/file")
    public class FileController { 
    
        /** * 跨服务器文件上传 * * @return */
        @RequestMapping("/fileupload3")
        public String fileuoload3(MultipartFile upload) throws Exception { 
            System.out.println( "跨服务器文件上传..." );
    
            // 定义上传文件服务器路径
            //String path = "http://localhost:8081/uploads/";
            String path = "http://localhost:8081/fileupload_server/uploads/";
            System.out.println( "上传的位置：" + path );
    
            // 说明上传文件项
            // 获取上传文件的名称
            String filename = upload.getOriginalFilename();
            // 把文件的名称设置唯一值，uuid
            String uuid = UUID.randomUUID().toString().replace( "-", "" );
            filename = uuid + "_" + filename;
    
            // 创建客户端的对象
            Client client = Client.create();
    
            // 和图片服务器进行连接
            WebResource webResource = client.resource( path + filename );
    
            // 上传文件
            webResource.put( upload.getBytes() );
    
            System.out.println( "跨服务器文件上传文件上传成功..." );
            return "success";
        }
    
        /** * SpringMVC文件上传 * upload名称必须与jsp页面的name一样 * MultipartFile upload * name="upload" * * @return */
        @RequestMapping("/fileupload2")
        public String fileuoload2(HttpServletRequest request, MultipartFile upload) throws Exception { 
            System.out.println( "springmvc文件上传..." );
    
            // 使用fileupload组件完成文件上传
            // 上传的位置
            String path = request.getSession().getServletContext().getRealPath( "/uploads/" );
            System.out.println( "上传的位置：" + path );
            // 判断，该路径是否存在
            File file = new File( path );
            if (!file.exists()) { 
                // 创建该文件夹
                file.mkdirs();
            }
    
            // 说明上传文件项
            // 获取上传文件的名称
            String filename = upload.getOriginalFilename();
            // 把文件的名称设置唯一值，uuid
            String uuid = UUID.randomUUID().toString().replace( "-", "" );
            filename = uuid + "_" + filename;
            // 完成文件上传
            upload.transferTo( new File( path, filename ) );
    
            System.out.println( "springmvc文件上传成功..." );
            return "success";
        }
    
        /** * 文件上传,传统文件上传 * * @return */
        @RequestMapping("/fileupload1")
        public String fileuoload1(HttpServletRequest request) throws Exception { 
            System.out.println( "文件上传..." );
    
            // 使用fileupload组件完成文件上传
            // 上传的位置
            String path = request.getSession().getServletContext().getRealPath( "/uploads/" );
            System.out.println( "上传的位置：" + path );
            // 判断，该路径是否存在
            File file = new File( path );
            if (!file.exists()) { 
                // 创建该文件夹
                file.mkdirs();
            }
    
            // 解析request对象，获取上传文件项
            DiskFileItemFactory factory = new DiskFileItemFactory();
            ServletFileUpload upload = new ServletFileUpload( factory );
            // 解析request
            List<FileItem> items = upload.parseRequest( request );
            // 遍历
            for (FileItem item : items) { 
                // 进行判断，当前item对象是否是上传文件项
                if (item.isFormField()) { 
                    // 说明普通表单向
                } else { 
                    // 说明上传文件项
                    // 获取上传文件的名称
                    String filename = item.getName();
                    // 把文件的名称设置唯一值，uuid，防止上传相同图片覆盖问题
                    String uuid = UUID.randomUUID().toString().replace( "-", "" );
                    filename = uuid + "_" + filename;
                    // 完成文件上传
                    item.write( new File( path, filename ) );
                    // 删除临时文件
                    item.delete();
                }
            }
            System.out.println( "传统文件上传文件上传成功..." );
            return "success";
        }
    
    }

1.  jsp

<%--
      Created by IntelliJ IDEA.
      User: zrj
      Date: 2021/1/2
      Time: 11:35
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>index</title>
    </head>
    <body>
    
        <h3>传统文件上传</h3>
    
        <form action="file/fileupload1" method="post" enctype="multipart/form-data">
            选择文件：<input type="file" name="upload" /><br/>
            <input type="submit" value="上传" />
        </form>
    
        <h3>Springmvc文件上传</h3>
    
        <form action="file/fileupload2" method="post" enctype="multipart/form-data">
            选择文件：<input type="file" name="upload" /><br/>
            <input type="submit" value="上传" />
        </form>
    
        <h3>跨服务器文件上传</h3>
    
        <form action="file/fileupload3" method="post" enctype="multipart/form-data">
            选择文件：<input type="file" name="upload" /><br/>
            <input type="submit" value="上传" />
        </form>
    
    </body>
    </html>

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