利用MultipartFile实现文件上传

利用MultipartFile实现文件上传

在java中上传文件似乎总有点麻烦,没.net那么简单,记得最开始的时候用smartUpload实现文件上传,最近在工作中使用spring的MultipartFile实现文件上传,感觉挺简单,在这里和大家分享一下.

一.主要有两个java类,和一般的servlet放在一起即可.

1.FileUploadBean.java

packagechb.demo.web;

importorg.springframework.web.multipart.MultipartFile;

/***//**
*@authorchb
*
*/
publicclassFileUploadBean...{

privateMultipartFilefile;

publicvoidsetFile(MultipartFilefile)...{
this.file=file;
}

publicMultipartFilegetFile()...{
returnfile;
}
}

2.FileUploadController.java

packagechb.demo.web;

importjava.io.FileOutputStream;
importjava.io.IOException;
importjava.io.InputStream;

importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;

importorg.springframework.validation.BindException;
importorg.springframework.web.multipart.MultipartFile;
importorg.springframework.web.servlet.ModelAndView;
importorg.springframework.web.servlet.mvc.SimpleFormController;


/***//**
*@authorchb
*
*/
publicclassFileUploadControllerextendsSimpleFormController...{

protectedModelAndViewonSubmit(
HttpServletRequestrequest,
HttpServletResponseresponse,
Objectcommand,
BindExceptionerrors)...{

try
...{
//castthebean
FileUploadBeanbean=(FileUploadBean)command;

//let'sseeifthere'scontentthere
MultipartFilefile=bean.getFile();

if(file==null)...{
thrownewException("上传失败：文件为�空");
}
if(file.getSize()>10000000)
...{
thrownewException("上传失败：文件大小不能超过10M");
}
//得到文件�名
Stringfilename=file.getOriginalFilename();

if(file.getSize()>0)...{
try...{
SaveFileFromInputStream(file.getInputStream(),"D:/",filename);
}catch(IOExceptione)...{
System.out.println(e.getMessage());
returnnull;
}
}
else...{
thrownewException("上传失败：上传文件不能为�空");
}
//well,let'sdonothingwiththebeanfornowandreturn:
try...{
returnsuper.onSubmit(request,response,command,errors);

}catch(Exceptione)...{
System.out.println(e.getMessage());
returnnull;
}
}
catch(Exceptionex)
...{
System.out.println(ex.getMessage());
returnnull;
}
}

/***//**保存文件
*@paramstream
*@parampath
*@paramfilename
*@throwsIOException
*/
publicvoidSaveFileFromInputStream(InputStreamstream,Stringpath,Stringfilename)throwsIOException
...{
FileOutputStreamfs=newFileOutputStream(path+"/"+filename);
byte[]buffer=newbyte[1024*1024];
intbytesum=0;
intbyteread=0;
while((byteread=stream.read(buffer))!=-1)
...{
bytesum+=byteread;
fs.write(buffer,0,byteread);
fs.flush();
}
fs.close();
stream.close();
}
}

二.配置文件中如下配置:

1.web.xml,利用spring mvc模式,大家应该都很熟悉了

<servlet>
<servlet-name>chb</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
<servlet-name>chb</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>

2.chb-servlet.xml,这里要配置映射,并可以设定最大可上传文件的大小

<?xmlversion="1.0"encoding="UTF-8"?>
<!DOCTYPEbeansPUBLIC"-//SPRING//DTDBEAN//EN""http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<!--Multi-Action用来标识method的变量名定义-->
<beanid="methodNameResolver"class="org.springframework.web.servlet.mvc.multiaction.ParameterMethodNameResolver">
<propertyname="paramName">
<value>action</value>
</property>
<propertyname="defaultMethodName">
<value>index</value>
</property>
</bean>

<beanid="multipartResolver"class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!--oneofthepropertiesavailable;themaximumfilesizeinbytes-->
<propertyname="maxUploadSize"value="10000000"/>
</bean>


<beanid="handlerMapping"class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
<propertyname="mappings">
<props>
<propkey="/upload.do">fileUploadController</prop>
</props>
</property>
</bean>

<beanid="fileUploadController"class="chb.demo.web.FileUploadController">
<propertyname="commandClass"value="chb.demo.web.FileUploadBean"/>
<!--上传失败时跳转页面-->
<propertyname="formView"value="/user/err.jsp"/>
<!--上传成功时跳转页面-->
<propertyname="successView"value="/user/confirmation.jsp"/>
</bean>
</beans>

三.设定jsp页面

<formid="form1"method="post"action="upload.do"enctype="multipart/form-data">
<tr>
<tdwidth="25%"align="right">上传文件：</td>
<td><inputid="file"type="file"NAME="file"style="width:300px;"></td>
</tr>
<tralign="center"valign="middle">
<tdheight="60"colspan="2"><inputtype="submit"ID="BtnOK"value="确认上传"></td>
</tr>
</form>

ok,现在就可以上传文件了,挺简单吧?这里我只列出了基本步骤,至于具体的操作(比如中文问题)可能就需要大家自己再完善完善了.