140_SpringMVC 文件上传下载
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目录
准备工作
编写基础
新建web子模块
添加web框架支持
编写web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!--注册DispatcherServlet，这个是SpringMVC的核心：请求分发器，前置控制器-->
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--DispatcherServlet要绑定SpringMVC的配置文件-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</init-param>
<!--启动级别设置为1-->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<!--
在SpringMVC中，/ 和 /*
/：匹配所有的请求，不会匹配jsp页面
/*：匹配所有的请求，包括jsp页面
-->
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<!--编码过滤器-->
<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>
</web-app>
编写applicationContext.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: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">
<!--自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
<context:component-scan base-package="com.qing.controller"/>
<!--让SpringMVC不处理静态资源，如：.css .js .html .mp3 .mp4-->
<mvc:default-servlet-handler/>
<!--
支持MVC注解驱动
在spring中一般采用@RequestMapping注解来完成映射关系
要想使@RequestMapping注解生效，必须向上下文中注册DefaultAnnotationHandlerMapping和一个AnnotationMethodHandlerAdapter实例
这两个实例分别在类和方法级别处理
而annotation-driven配置帮助我们自动完成上述两个实例的注入
-->
<mvc:annotation-driven>
<!--配置消息转换，解决乱码问题-->
<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>
<!--视图解析器-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<!--前缀和后缀-->
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
编写com.qing.controller包
Artifacts创建lib
配置Tomcat
测试
文件上传
pom.xml添加文件上传依赖
<?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">
<parent>
<artifactId>spring-mvc</artifactId>
<groupId>com.qing</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>springmvc-06-file</artifactId>
<dependencies>
<!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
</dependency>
</dependencies>
</project>
Artifacts下lib中添加jar
applicationContext.xml配置文件上传
<?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/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">
<!--自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
<context:component-scan base-package="com.qing.controller"/>
<!--让SpringMVC不处理静态资源，如：.css .js .html .mp3 .mp4-->
<mvc:default-servlet-handler/>
<!--
支持MVC注解驱动
在spring中一般采用@RequestMapping注解来完成映射关系
要想使@RequestMapping注解生效，必须向上下文中注册DefaultAnnotationHandlerMapping和一个AnnotationMethodHandlerAdapter实例
这两个实例分别在类和方法级别处理
而annotation-driven配置帮助我们自动完成上述两个实例的注入
-->
<mvc:annotation-driven>
<!--配置消息转换，解决乱码问题-->
<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>
<!--视图解析器-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<!--前缀和后缀-->
<property name="prefix" value="/WEB-INF/jsp/"/>
<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>
编写文件上传页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/upload" method="post" enctype="multipart/form-data">
<input type="file" name="file"/>
<input type="submit" value="upload"/>
</form>
</body>
</html>
编写FileController
package com.qing.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 java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.UUID;
@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
*
* @param file
* @param request
* @return
* @throws IOException
*/
@RequestMapping("/upload")
public String upload(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
// 获取文件名
String originalFilename = file.getOriginalFilename();
// 如果文件名为空，说明没有上传，直接回到文件上传页
if ("".equals(originalFilename)) {
return "redirect:/index.jsp";
}
String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));
System.out.println("上传的文件名：" + originalFilename);
// 上传文件保存路径
String path = request.getServletContext().getRealPath("/upload");
// 如果路径不存在，创建
File realPath = new File(path);
if (! realPath.exists()) {
realPath.mkdir();
}
System.out.println("上传文件保存路径：" + realPath);
// 文件输入流
InputStream is = file.getInputStream();
// 文件输出流
String fileName = UUID.randomUUID().toString() + suffix;
FileOutputStream os = new FileOutputStream(new File(realPath,fileName));
// 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();
System.out.println("文件保存成功，文件名：" + fileName);
return "redirect:/index.jsp";
}
/**
* 通过CommonsMultipartFile的file.transferTo方法保存上传的文件
* @param file
* @param request
* @return
* @throws IOException
*/
@RequestMapping("/upload2")
public String upload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
String originalFilename = file.getOriginalFilename();
String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));
// 上传文件保存路径
String path = request.getServletContext().getRealPath("/upload");
// 如果路径不存在，创建
File realPath = new File(path);
if (! realPath.exists()) {
realPath.mkdir();
}
System.out.println("上传文件保存路径：" + realPath);
// 通过CommonsMultipartFile的方法直接写文件
String fileName = UUID.randomUUID().toString() + suffix;
file.transferTo(new File(realPath + "/" + fileName));
System.out.println("文件保存成功，文件名：" + fileName);
return "redirect:/index.jsp";
}
}
测试
文件下载
步骤
编码
package com.qing.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.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.util.UUID;
@Controller
public class FileController {
@RequestMapping("/download")
public String download(HttpServletRequest request, HttpServletResponse response) throws IOException {
// 要下载的文件地址
String realPath = request.getServletContext().getRealPath("/upload");
String fileName = "c83781a5-45d7-43a0-bbcc-e6ab84f7c11f.docx";
// 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
response.setHeader("Content-Disposition","attachment;fileName=" + URLEncoder.encode(fileName,"UTF-8")); // 响应头
// 读取文件--输入流
File file = new File(realPath,fileName);
FileInputStream is = new FileInputStream(file);
// 写出文件--输出流
OutputStream out = response.getOutputStream();
// 执行写出操作
int len = 0;
byte[] buffer = new byte[1024];
while ((len=is.read(buffer)) != -1) {
out.write(buffer,0,len);
out.flush();
}
out.close();
is.close();
return "OK";
}
}
测试
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