利用MultipartFile实现文件上传功能

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.

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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