servlet+JSP+mysql實現文件上傳的方法

本文實例講述了servlet+JSP+mysql實現文件上傳的方法。分享給大家供大家參考，具體如下：

一、文件上傳的基本操作：

1、表單屬性enctype的設置

multipart/form-data和application/x-www-form-urlencoded的區別

FORM元素的enctype屬性指定了表單數據向服務器提交時所采用的編碼類型，默認的缺省值是“application/x-www-form-urlencoded”。

然而，在向服務器發送大量的文本、包含非ASCII字符的文本或二進制數據時這種編碼方式效率很低。

在文件上載時，所使用的編碼類型應當是“multipart/form-data”，它既可以發送文本數據，也支持二進制數據上載。

Browser端<form>表單的ENCTYPE屬性值為multipart/form-data，它告訴我們傳輸的數據要用到多媒體傳輸協議，由于多媒體傳輸的都是大量的數據，所以規定上傳文件必須是post方法，<input>的type屬性必須是file。

實現過程：

package cn.csdn.web.servlet;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.sql.SQLException;

import java.util.List;

import java.util.UUID;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.sql.DataSource;

import org.apache.commons.dbutils.QueryRunner;

import org.apache.commons.fileupload.FileItem;

import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException;

import org.apache.commons.fileupload.FileUploadException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

import cn.csdn.web.c3p0.DBManager_c3p0;

public class Upload2Servlet extends HttpServlet {

/**

*

*/

private static final long serialVersionUID = 1L;

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doPost(request,response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

request.setCharacterEncoding("UTF-8");

try {

//實例化一個文件工廠

DiskFileItemFactory factory=new DiskFileItemFactory();

factory.setRepository(new File("C://osp"));

String paramName=null;

String paramValue=null;

//配置上傳組件ServletFileUpload

ServletFileUpload upload=new ServletFileUpload(factory);

upload.setHeaderEncoding("UTF-8");

upload.setFileSizeMax(1024*1024);

//從request得到所有上傳域的列表

List<FileItem> list=upload.parseRequest(request);

for(FileItem item:list){

//如果是上傳域的文件域

if(item.isFormField()){

//表單普通輸入項

paramName = item.getFieldName(); //上傳于的Name

// String paramValue=item.getString();

// paramValue=new String(paramValue.getBytes("iso8859-1"),"UTF-8");

paramValue=item.getString("UTF-8");

System.out.println(paramName+"="+paramValue);

}else{

//上傳文件處理

String fileName = item.getName();

fileName=fileName.substring(fileName.lastIndexOf("//")+1); //截取擴展名

System.out.println("name="+fileName);

if(!fileName.equals("")){

// fileName=refactorFileName(fileName);

InputStream in=item.getInputStream();

File file = new File("c://"+fileName);

FileOutputStream os=new FileOutputStream(file);

byte[] buf = new byte[1024];

int len=0;

while((len=in.read(buf))>0){

os.write(buf,0,len);

}

os.flush();

os.close();

in.close();

item.delete();

request.setAttribute("message", "文件上傳成功");

try {

DataSource ds = DBManager_c3p0.getDataSource();

QueryRunner runner = new QueryRunner(ds);

String sql = "insert into user(name,file) values(?,?)";

Object[] params = {paramValue,fileName};

runner.update(sql, params);

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

} catch(FileSizeLimitExceededException e1){

e1.printStackTrace();

request.setAttribute("message", "文件尺寸太大");

}catch (FileUploadException e) {

// TODO Auto-generated catch block

e.printStackTrace();

request.setAttribute("message", "文件上傳失敗");

}

request.getRequestDispatcher("/message.jsp").forward(request, response);

}

// public String refactorFileName(String fileName){

// return UUID.randomUUID().toString()+"_"+fileName;

// }

}