SpringMVC实现单文件上传
SpringMVC提供了即插即用的CommonsMultipartResolver类来支持文件上传,该类依赖于Apache Commons FileUpload组件。因此必须导入commons-fileupload.jar和commons-io.jar,若缺少这两个jar包,则会导致如下异常:
java.lang.NoClassDefFoundError: org/apache/commons/fileupload/FileItemFactory
在FileUploadController类中,设置请求映射路径(@RequestMapping)为”/upload”,这与fileUpload.jsp
中form标签的action属性的值相对应,表示文件上传请求由该方法处理。
FileUploadController.java
import java.io.File;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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;
@Controller
public class FileUploadController {
//创建日志对象
private static final Log logger = LogFactory.getLog(FileUploadController.class);
@RequestMapping(value="/upload",method=RequestMethod.POST)
public String upload(HttpServletRequest request,
//上传文件会自动保存到MultipartFile中
@RequestParam("file") MultipartFile file) throws Exception {
//记录上传文件的原文件名
logger.info(file.getOriginalFilename());
if(!file.isEmpty()) {
String path = "c:\\upload";
String fileName = file.getOriginalFilename();
file.transferTo(new File(path + File.separator + System.currentTimeMillis() + fileName));
}
return "success";
}
}
文件上传时,必须在form标签中设置enctype属性,值为”multipart/form-data”,浏览器会采用二进制流的方式处理表单数据。
fileUpload.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>FileUpload</title>
</head>
<body>
<h2>文件上传</h2>
<form action="upload" enctype="multipart/form-data" method="post">
<table>
<tr>
<td>请选择文件:</td>
<td><input type="file" name="file"/></td>
</tr>
<tr>
<td><input type="submit" value="上传"/></td>
</tr>
</table>
</form>
</body>
</html>
SpringMVC配置文件中默认没有装配CommonsMultipartResolver类,因此不能进行文件上传,若想用,则需要配置,配置文件如下所示:
dispatcher-config.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-4.3.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-4.3.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.3.xsd">
<!-- 启用Spring关于annotation的DI,以便在Spring-MVC中使用Spring强大的功能。激活@Required @Autowired @Resource 等标注 -->
<context:annotation-config/>
<!-- 1.扩充了注解驱动,可以将请求参数绑定到控制器参数
2.自动注册了RequestMappingHandlerMapping和RequestMappingHandlerAdapter两个bean
3.@NumberFormatannotation支持
4.@DateTimeFormat支持
5.@Valid支持
6.读写XML文件的支持(JAXB)
7.读写JSON的支持
-->
<mvc:annotation-driven/>
<!-- 使用默认的Servlet响应静态文件。如js,css,image等 -->
<mvc:default-servlet-handler/>
<!-- 只管理Controller类型的bean,忽略其它类型的bean,如@Service -->
<context:component-scan base-package="org.zpc.controller" >
<context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
<!-- 对模型视图名称的解析,即在模型视图名称添加前后缀 -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"
p:prefix="/WEB-INF/jsp/"
p:suffix=".jsp" />
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- 上传文件的大小限制,单位为字节(10MB)-->
<property name="maxUploadSize" value="10485760"/>
<!-- 请求的编码格式,必须和JSP页面的pageEncoding属性保持一致 -->
<property name="defaultEncoding" value="UTF-8"/>
<!-- 启用延迟加载,用于真正需要时再上传,提高性能 -->
<property name="resolveLazily" value="true"/>
</bean>
</beans>
success.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Success</title>
</head>
<body>
<h2 align="center">Success</h2>
</body>
</html>
扩展:
Multipart类中有如下常用方法:
- byte[] getBytes(). 获取文件数据
- String getContentType(). 获取文件的MIME类型
- void transferTo(File dest). 将上传的文件保存到目标文件夹中
- long getSize(). 获取文件的大小(byte)
- boolean isEmpty(). 判断文件是否为空
- InputStream getInputStream(). 获取文件流
- String getName(). 获取表单中文件组件名
- String getOriginalFilename(). 获取原上传名