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


package chb.demo.web;




import org.springframework.web.multipart.MultipartFile;






/** *//**


* @author chb


*


*/




public class FileUploadBean ...{




private MultipartFile file;






public void setFile(MultipartFile file) ...{


this.file = file;


}






public MultipartFile getFile() ...{


return file;


}


}

2.FileUploadController.java


package chb.demo.web;




import java.io.FileOutputStream;


import java.io.IOException;


import java.io.InputStream;




import javax.servlet.http.HttpServletRequest;


import javax.servlet.http.HttpServletResponse;




import org.springframework.validation.BindException;


import org.springframework.web.multipart.MultipartFile;


import org.springframework.web.servlet.ModelAndView;


import org.springframework.web.servlet.mvc.SimpleFormController;








/** *//**


* @author chb


*


*/




public class FileUploadController extends SimpleFormController ...{





protected ModelAndView onSubmit(


HttpServletRequest request,


HttpServletResponse response,


Object command,




BindException errors)...{





try




...{


// cast the bean


FileUploadBean bean = (FileUploadBean) command;




// let's see if there's content there


MultipartFile file = bean.getFile();







if (file == null) ...{


throw new Exception("上传失败：文件为�空");


}


if(file.getSize()>10000000)




...{


throw new Exception("上传失败：文件大小不能超过10M");


}


//得到文件�名


String filename=file.getOriginalFilename();







if(file.getSize()>0)...{




try ...{


SaveFileFromInputStream(file.getInputStream(),"D:/",filename);




} catch (IOException e) ...{


System.out.println(e.getMessage());


return null;


}


}




else...{


throw new Exception("上传失败：上传文件不能为�空");


}


// well, let's do nothing with the bean for now and return:




try ...{


return super.onSubmit(request, response, command, errors);







} catch (Exception e) ...{


System.out.println(e.getMessage());


return null;


}


}


catch(Exception ex)




...{


System.out.println(ex.getMessage());


return null;


}


}







/** *//**保存文件


* @param stream


* @param path


* @param filename


* @throws IOException


*/


public void SaveFileFromInputStream(InputStream stream,String path,String filename) throws IOException




...{


FileOutputStream fs=new FileOutputStream( path + "/"+ filename);


byte[] buffer =new byte[1024*1024];


int bytesum = 0;


int byteread = 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


<?xml version="1.0" encoding="UTF-8"?>


<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">


<beans>


<!-- Multi-Action 用来标识method的变量名定义-->


<bean id="methodNameResolver" class="org.springframework.web.servlet.mvc.multiaction.ParameterMethodNameResolver">


<property name="paramName">


<value>action</value>


</property>


<property name="defaultMethodName">


<value>index</value>


</property>


</bean>





<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">


<!-- one of the properties available; the maximum file size in bytes -->


<property name="maxUploadSize" value="10000000"/>


</bean>







<bean id="handlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">


<property name="mappings">


<props>


<prop key="/upload.do">fileUploadController</prop>


</props>


</property>


</bean>





<bean id="fileUploadController" class="chb.demo.web.FileUploadController">


<property name="commandClass" value="chb.demo.web.FileUploadBean"/>


<!-- 上传失败时跳转页面 -->


<property name="formView" value="/user/err.jsp"/>


<!-- 上传成功时跳转页面 -->


<property name="successView" value="/user/confirmation.jsp"/>


</bean>


</beans>

三.设定jsp页面


<form id="form1" method="post" action="upload.do" enctype="multipart/form-data">


<tr>


<td width="25%" align="right">上传文件：</td>


<td><input id="file" type="file" NAME="file" style="width:300px;"></td>


</tr>


<tr align="center" valign="middle">


<td height="60" colspan="2"><input type="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.