最近的项目中用到了文件的上传和下载功能，任务分配给了其他的同时完成。如今项目结束告一段落，我觉着这个功能比较重要，因此特意把它提取出来自己进行了尝试。
一、 基础配置：
maven导包及配置pom.xml，导包时除开springmvc的基础依赖外，需要导入文件上传下载时用到的commons-io.jsr和commons-fileupload.jar：
<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/maven-v4_0_0.xsd">
<modelversion>4.0.0</modelversion>
<groupid>filloadtest</groupid>
<artifactid>filloadtest</artifactid>
<packaging>war</packaging>
<version>0.0.1-snapshot</version>
<name>filloadtest maven webapp</name>
<url>http://maven.apache.org</url>
<build>
<finalname>filloadtest</finalname>
<plugins>
<!-- 以下配置可以保证每次强制更新时jre版本不会变化，那我的eclipse4.4.1，maven3.2.5为例，如果不设置这个，每次强制更新时jre就会变回1.5 -->
<plugin>
<artifactid>maven-compiler-plugin</artifactid>
<version>2.3.2</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
<encoding>utf-8</encoding>
<compilerarguments>
<verbose />
<bootclasspath>${java.home}\lib\rt.jar</bootclasspath>
</compilerarguments>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupid>junit</groupid>
<artifactid>junit</artifactid>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<groupid>org.springframework</groupid>
<artifactid>spring-webmvc</artifactid>
<version>4.0.6.release</version>
<groupid>com.fasterxml.jackson.core</groupid>
<artifactid>jackson-annotations</artifactid>
<version>2.2.3</version>
<artifactid>jackson-core</artifactid>
<artifactid>jackson-databind</artifactid>
<groupid>commons-fileupload</groupid>
<artifactid>commons-fileupload</artifactid>
<version>1.3.1</version>
<groupid>commons-io</groupid>
<artifactid>commons-io</artifactid>
<version>2.4</version>
</dependencies>
</project>
web.xml基础配置：
<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemalocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="webapp_id" version="2.5">
<filter>
<description>字符集过滤器</description>
<filter-name>encodingfilter</filter-name>
<filter-class>org.springframework.web.filter.characterencodingfilter</filter-class>
<init-param>
<description>字符集编码</description>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<url-pattern>/*</url-pattern>
</filter-mapping>
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.dispatcherservlet</servlet-class>
<init-param>
<param-name>contextconfiglocation</param-name>
<param-value>classpath:spring.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
spring基础配置spring.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:mvc="http://www.springframework.org/schema/mvc"
xsi:schemalocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:annotation-config />
<mvc:annotation-driven />
<context:component-scan base-package="controllers" />
<!-- 避免ie执行ajax时,返回json出现下载文件 -->
<bean id="mappingjacksonhttpmessageconverter"
class="org.springframework.http.converter.json.mappingjackson2httpmessageconverter">
<property name="supportedmediatypes">
<list>
<value>text/html;charset=utf-8</value>
</list>
</property>
</bean>
<!-- 启动spring mvc的注解功能，完成请求和注解pojo的映射 -->
<bean
class="org.springframework.web.servlet.mvc.annotation.annotationmethodhandleradapter">
<property name="messageconverters">
<ref bean="mappingjacksonhttpmessageconverter" /><!-- json转换器 -->
<!-- 支持上传文件 -->
<bean id="multipartresolver"
class="org.springframework.web.multipart.commons.commonsmultipartresolver" >
<!-- 100m -->
<property name="maxuploadsize" value="104857600"></property>
<property name="defaultencoding" value="utf-8"></property>
</beans>
二、文件上传的代码
上传的简单页面index.html,要注意form表单提交时的entype的设置：
<!doctype html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
</head>
<body>
<form action="./uploadfile.do" method="post" enctype="multipart/form-data">
选择文件：<input type="file" name="file"/>
<input type="submit" value="提交"/>
</form>
</body>
</html>
上传对应的后台java代码，具体问题见注释：
package controllers;
import java.io.file;
import java.io.ioexception;
import java.util.iterator;
import javax.servlet.http.httpservletrequest;
import org.apache.commons.io.fileutils;
import org.springframework.http.httpheaders;
import org.springframework.http.httpstatus;
import org.springframework.http.mediatype;
import org.springframework.http.responseentity;
import org.springframework.stereotype.controller;
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.requestmethod;
import org.springframework.web.bind.annotation.requestparam;
import org.springframework.web.multipart.multipartfile;
import org.springframework.web.multipart.multiparthttpservletrequest;
import org.springframework.web.multipart.commons.commonsmultipartresolver;
@controller
public class filecontroller {
/**
* 文件上传
*
* @author：tuzongxun
* @title: uploadfile
* @param @param file
* @param @param request
* @param @throws illegalstateexception
* @param @throws ioexception
* @return void
* @date apr 28, 2016 1:22:00 pm
* @throws
*/
@requestmapping(value = "/uploadfile.do", method = requestmethod.post)
public void uploadfile(httpservletrequest request)
throws illegalstateexception, ioexception {
// @requestparam("file") multipartfile file,
commonsmultipartresolver multipartresolver = new commonsmultipartresolver(
request.getsession().getservletcontext());
// 判断 request 是否有文件上传,即多部分请求
if (multipartresolver.ismultipart(request)) {
// 转换成多部分request
multiparthttpservletrequest multirequest = (multiparthttpservletrequest) request;
// 取得request中的所有文件名
iterator<string> iter = multirequest.getfilenames();
while (iter.hasnext()) {
// 取得上传文件
multipartfile f = multirequest.getfile(iter.next());
if (f != null) {
// 取得当前上传文件的文件名称
string myfilename = f.getoriginalfilename();
// 如果名称不为“”,说明该文件存在，否则说明该文件不存在
if (myfilename.trim() != "") {
// 定义上传路径
string path = "c:\\users\\tuzongxun123\\desktop\\"
+ myfilename;
file localfile = new file(path);
f.transferto(localfile);
}
}
}
}
}
}
页面效果图如下，当选择文件提交后，便会看到选中的文件被传到了代码中指定的位置，这里是我的桌面上。