JSP + servlet 源码 实现文件的上传
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JSP页面
upLoad.jsp
_________________________________
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>uoLoad</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<form action="MyUpLoadServlet" method="post"
enctype="multipart/form-data">
请选择文件：<input id="myfile" name="myfile" type="file"
onchange="showPreview(this)" /> <input type="submit" value="提交" />${result}
</form>
</body>
</html>
servlet
package com.agd.servlet;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/MyUpLoadServlet")
public class MyUpLoadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
//开始位置
String image="image";
copy2(request, image);
//结束位置
request.setAttribute("result", "上传成功！");
RequestDispatcher dispatcher = request.getRequestDispatcher("success.jsp");
dispatcher.forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
protected void copy2(HttpServletRequest request,String url ) throws ServletException, IOException {
//从request当中获取流信息
InputStream fileSource=request.getInputStream();
String tempFileName="E:/tempFile";
//指向临时文件
File tempFile=new File(tempFileName);
//outPutStream 文件输出流指向这个临时文件
@SuppressWarnings("resource")
FileOutputStream outputStream=new FileOutputStream(tempFile);
//开始读写数据
byte[] b=new byte[1024];
int len=0;
while((len=fileSource.read(b))!=-1){
outputStream.write(b, 0, len);
}
//关闭输出流输入流
outputStream.close();
fileSource.close();
System.out.println("上传成功");
//获取文件上传的名称
RandomAccessFile randomFile=new RandomAccessFile(tempFile, "r");
randomFile.readLine();//读取第一行数据
String str=randomFile.readLine();//读取第二行数据
//临时文件第一行和最后一行都是不需要的
System.out.println(str);
String str1=str.substring(0,str.lastIndexOf("\""));//根据最后一个引号来定位
System.out.println(str1);
int endIndex=str.lastIndexOf("\"");
int beginIndex=str1.lastIndexOf("\"")+1;//beginIndex,endIndex得到文件name的初始位置
String filename=str.substring(beginIndex,endIndex);
filename=new String(filename.getBytes("ISO-8859-1"),"utf-8");
System.out.println("filename"+filename);
//重新定位文件指针到文件头
randomFile.seek(0);
long startPosition=0;
int i=1;
byte n;
//获取文件内容,开始位置
while((n=randomFile.readByte())!=-1&&i<=4){
if(n==‘\n‘){
startPosition=randomFile.getFilePointer();//getFilePointer()用于定位
i++;
}
}
startPosition = randomFile.getFilePointer() -1;
//获取文件内容 结束位置
randomFile.seek(randomFile.length());
long endPosition = randomFile.getFilePointer();
int j = 1;
while(endPosition >=0 && j<=2){
endPosition--;
randomFile.seek(endPosition);
if(randomFile.readByte() == ‘\n‘){
j++;
}
}
endPosition = endPosition -1;
//设置保存上传文件的路径
String realPath =getServletContext().getRealPath("/") + url;//为文件保存的绝对路径
System.out.println(realPath);
File fileupload = new File(realPath);
if(!fileupload.exists()){
fileupload.mkdir();
}
File saveFile = new File(realPath,filename);
RandomAccessFile randomAccessFile = new RandomAccessFile(saveFile,"rw");
//从临时文件当中读取文件内容（根据起止位置获取）
randomFile.seek(startPosition);
while(startPosition < endPosition){
randomAccessFile.write(randomFile.readByte());
startPosition = randomFile.getFilePointer();
}
System.out.println("最终版成功");
//关闭输入输出流、删除临时文件
randomAccessFile.close();
randomFile.close();
tempFile.delete(); //删除临时文件，
}
}
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