文件上传
同时构建这个controller的过程中遇到最大的一个bug是：
得构建一个视图资源管理器，因为controller中必须得认识ModelAndView,String类型
没有ModelAndView对象,不知道如何去找视图,会自动给你默认的视图/upload,最后会使用视图解析器帮我们返回的地址添加前缀信息和后缀信息,/WEB-INF/upload.jsp.
配置视图解析器:(可以再spring-webmvc-4.1.2.RELEASE-sources.jar/org/springframework/web/servlet/DispatcherServlet.properties中的org.springframework.web.servlet.ViewResolver)
文件下载
文件具体格式
具体代码：
appilication.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:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:jee="http://www.springframework.org/schema/jee"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/jeehttp://www.springframework.org/schema/jee/spring-jee.xsd
http://www.springframework.org/schema/aophttp://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="uploadfile"></context:component-scan>
<mvc:annotation-driven></mvc:annotation-driven>
<mvc:default-servlet-handler></mvc:default-servlet-handler>
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="maxUploadSize" value="1048576"></property>
</bean>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="suffix" value=".jsp"></property>
<property name="prefix" value="/WEB-INF/"></property>
</bean>
</beans>
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/javaeehttp://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>uploadfile</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:application.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>uploadfile</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
uploadfile.jsp
<%--
Created by IntelliJ IDEA.
User: Lenovo
Date: 2018/11/23
Time: 13:05
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<fieldset>
<legend>文件上传</legend>
<form enctype="multipart/form-data" method="post" action="/upload">
<input type="file" name="file"/><br><br>
<input type="submit" name="btn" value="文件上传">
</form>
</fieldset>
</body>
</html>
upload控制器
package uploadfile;
import org.apache.commons.io.IOUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
@Controller
public class upload {
@RequestMapping("/upload")
public void upload(MultipartFile file){
InputStream is=null;
OutputStream os=null;
try {
is=file.getInputStream();
os=new FileOutputStream(new File("D:/b.jsp"));
IOUtils.copy(is,os);
}catch (Exception e){
e.printStackTrace();
}finally {
if(is!=null){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}finally {
if(os!=null){
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
}
@RequestMapping("/download")
public void download(HttpServletResponse resp){
FileInputStream is=null;
try {
resp.setHeader("Content-Disposition","attachment;filename=a.jpg");
is=new FileInputStream(new File("D:/a.jpg"));
ServletOutputStream os=resp.getOutputStream();
IOUtils.copy(is,os);
}catch (Exception e){
e.printStackTrace();
}finally {
if(is!=null){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
};
}
}
}
运行结果为：
