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
143fe
 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.