jsp文件下载上传
❶ jsp如何实现文件上传与下载
如果服务器端程序使用的是struts2框架的话，我会，其他的不会。
struts2：
对于上传，jsp页面只需要有个file类型的表单域，如<input type="file" name="xxx" />
struts2的接收请求的action中再写三个属性与这个表单域的名称对应起来，他们是，File类型的xxx,String类型的xxxFileName,String类型的xxxContentType，并其设置相应的set/get方法。则框架负责接收上传文件的字节流，解析文件名，文件类型，直接使用即可。
对于下载，只需要在action的配置文件中设置如下返回值类型和相应参数：
<result type="stream">
<param name="contentType">application/octet-stream</param>
<param name="inputName">inputStream</param>
<param name="contentDisposition">attachment;filename=xxx </param> xxx为下载文件的文件名
</result>
且在action总写一个返回值类型为InputStream的getInputStream方法，此方法返回你要下载的文件的流即可。
ps:其中contentDisposition的配置信息中attachment代表点击下载时浏览器先弹出个保存位置的提示框，然后再决定是否下载，默认是inline，即直接打开文件。
❷ jsp上传下载文件的路径问题
jsp上传下载文件的路径是在服务器建立指定路径如下：
//接收上传文件内容中临时文件的文件名
String tempFileName = new String("tempFileName");
//tempfile 对象指向临时文件
File tempFile = new File("D:/"+tempFileName);
//outputfile 文件输出流指向这个临时文件
FileOutputStream outputStream = new FileOutputStream(tempFile);
//得到客服端提交的所有数据
InputStream fileSourcel = request.getInputStream();
//将得到的客服端数据写入临时文件
byte b[] = new byte[1000];
int n ;
while ((n=fileSourcel.read(b))!=-1){
outputStream.write(b,0,n);
}
//关闭输出流和输入流
outputStream.close();
fileSourcel.close();
//randomFile对象指向临时文件
RandomAccessFile randomFile = new RandomAccessFile(tempFile,"r");
//读取临时文件的第一行数据
randomFile.readLine();
//读取临时文件的第二行数据，这行数据中包含了文件的路径和文件名
String filePath = randomFile.readLine();
//得到文件名
int position = filePath.lastIndexOf('\\');
CodeToString codeToString = new CodeToString();
String filename = codeToString.codeString(filePath.substring(position,filePath.length()-1));
//重新定位读取文件指针到文件头
randomFile.seek(0);
//得到第四行回车符的位置，这是上传文件数据的开始位置
long forthEnterPosition = 0;
int forth = 1;
while((n=randomFile.readByte())!=-1&&(forth<=4)){
if(n=='\n'){
forthEnterPosition = randomFile.getFilePointer();
forth++;
}
}
//生成上传文件的目录
File fileupLoad = new File("D:/work space/JSP workspace/jsp_servlet_upAndLoad/file","upLoad");
fileupLoad.mkdir();
//saveFile 对象指向要保存的文件
File saveFile = new File("D:/work space/JSP workspace/jsp_servlet_upAndLoad/file/upLoad",filename);
RandomAccessFile randomAccessFile = new RandomAccessFile(saveFile,"rw");
//找到上传文件数据的结束位置，即倒数第四行
randomFile.seek(randomFile.length());
long endPosition = randomFile.getFilePointer();
int j = 1;
while((endPosition>=0)&&(j<=4)){
endPosition--;
randomFile.seek(endPosition);
if(randomFile.readByte()=='\n'){
j++;
}
}
//从上传文件数据的开始位置到结束位置，把数据写入到要保存的文件中
randomFile.seek(forthEnterPosition);
long startPoint = randomFile.getFilePointer();
while(startPoint<endPosition){
randomAccessFile.write(randomFile.readByte());
startPoint = randomFile.getFilePointer();
}
//关闭文件输入、输出
randomAccessFile.close();
randomFile.close();
tempFile.delete();
jsp文件下载选择路径：
//要下载的文件
File fileload = new File("D:/work space/JSP workspace/jsp_servlet_upAndLoad/file/upLoad",filename);
❸ jsp 文件的上传与下载 要求对文件的类型、大小进行选择判断
你下载一个 jspsmartupload 里不是有七个例子，其中一个就是了，你看看
❹ jsp怎么下载上传文件
去apache网站上下个common-fileupload上传组件用就可以了！
❺ 我想用jsp语言编写的网页中实现文件上传、下载的功能，请问完整的代码怎么写，尽量是最简单的，谢谢
<input type='file'>
然后设置form的 enctype= "multipart/form-data "
然后后台从HttpServletRequest里面取文件出来就ok了！
❻ 如何用JSP实现文件的上传和下载，要对数据库进行什么操作
你的表单呢？他的意思等你上传完成后，你要把文件信息更新到数据库，当你在向用户展示时，只需要查询数据即可。可以再数据库建一个表，吧相应字段存起来，最重要的是存上你的图片路径和名字。
❼ JSP做的简单的文件上传下载代码
//////////////////////用Servlvet实现文件上传,参考参考吧
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class UploadTest extends HttpServlet {
String rootPath, successMessage;
static final int MAX_SIZE = 102400;
public void init(ServletConfig config) throws ServletException
{
super.init(config);
}
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException
{
response.setContentType("text/html");
PrintWriter out = new PrintWriter (response.getOutputStream());
out.println("<html>");
out.println("<head><title>Servlet1</title></head>");
out.println("<body><form ENCTYPE=\"multipart/form-data\" method=post action=''><input type=file enctype=\"multipart/form-data\" name=filedata>");
out.println("<input type=submit></form>");
out.println("</body></html>");
out.close();
}
public void doPost(HttpServletRequest request,HttpServletResponse response)
{
ServletOutputStream out=null;
DataInputStream in=null;
FileOutputStream fileOut=null;
try
{
/*set content type of response and get handle to output stream in case we are unable to redirect client*/
response.setContentType("text/plain");
out = response.getOutputStream();
}
catch (IOException e)
{
//print error message to standard out
System.out.println("Error getting output stream.");
System.out.println("Error description: " + e);
return;
}
try
{
String contentType = request.getContentType();
//make sure content type is multipart/form-data
if(contentType != null && contentType.indexOf("multipart/form-data") != -1)
{
//open input stream from client to capture upload file
in = new DataInputStream(request.getInputStream());
//get length of content data
int formDataLength = request.getContentLength();
//allocate a byte array to store content data
byte dataBytes[] = new byte[formDataLength];
//read file into byte array
int bytesRead = 0;
int totalBytesRead = 0;
int sizeCheck = 0;
while (totalBytesRead < formDataLength)
{
//check for maximum file size violation
sizeCheck = totalBytesRead + in.available();
if (sizeCheck > MAX_SIZE)
{
out.println("Sorry, file is too large to upload.");
return;
}
bytesRead = in.read(dataBytes, totalBytesRead, formDataLength);
totalBytesRead += bytesRead;
}
//create string from byte array for easy manipulation
String file = new String(dataBytes);
//since byte array is stored in string, release memory
dataBytes = null;
/*get boundary value (boundary is a unique string that
separates content data)*/
int lastIndex = contentType.lastIndexOf("=");
String boundary = contentType.substring(lastIndex+1,
contentType.length());
//get Directory web variable from request
String directory="";
if (file.indexOf("name=\"Directory\"") > 0)
{
directory = file.substring(file.indexOf("name=\"Directory\""));
//remove carriage return
directory = directory.substring(directory.indexOf("\n")+1);
//remove carriage return
directory = directory.substring(directory.indexOf("\n")+1);
//get Directory
directory = directory.substring(0,directory.indexOf("\n")-1);
/*make sure user didn't select a directory higher in the directory tree*/
if (directory.indexOf("..") > 0)
{
out.println("Security Error: You can't upload " +"to a directory higher in the directory tree.");
return;
}
}
//get SuccessPage web variable from request
String successPage="";
if (file.indexOf("name=\"SuccessPage\"") > 0)
{
successPage = file.substring(file.indexOf("name=\"SuccessPage\""));
//remove carriage return
successPage = successPage.substring(successPage.indexOf("\n")+1);
//remove carriage return
successPage = successPage.substring(successPage.indexOf("\n")+1);
//get success page
successPage = successPage.substring(0,successPage.indexOf("\n")-1);}
//get OverWrite flag web variable from request
String overWrite;
if (file.indexOf("name=\"OverWrite\"") > 0)
{
overWrite = file.substring(file.indexOf("name=\"OverWrite\""));
//remove carriage return
overWrite = overWrite.substring(
overWrite.indexOf("\n")+1);
//remove carriage return
overWrite = overWrite.substring(overWrite.indexOf("\n")+1);
overWrite = overWrite.substring(0,overWrite.indexOf("\n")-1);
}
else
{
overWrite = "false";
}
//get OverWritePage web variable from request
String overWritePage="";
if (file.indexOf("name=\"OverWritePage\"") > 0)
{
overWritePage = file.substring(file.indexOf("name=\"OverWritePage\""));
//remove carriage return
overWritePage = overWritePage.substring(overWritePage.indexOf("\n")+1);
//remove carriage return
overWritePage = overWritePage.substring(overWritePage.indexOf("\n")+1);
//get overwrite page
overWritePage = overWritePage.substring(0,overWritePage.indexOf("\n")-1);
}
//get filename of upload file
String saveFile = file.substring(file.indexOf("filename=\"")+10);
saveFile = saveFile.substring(0,saveFile.indexOf("\n"));
saveFile = saveFile.substring(saveFile.lastIndexOf("\\")+1,
saveFile.indexOf("\""));
/*remove boundary markers and other multipart/form-data
tags from beginning of upload file section*/
int pos; //position in upload file
//find position of upload file section of request
pos = file.indexOf("filename=\"");
//find position of content-disposition line
pos = file.indexOf("\n",pos)+1;
//find position of content-type line
pos = file.indexOf("\n",pos)+1;
//find position of blank line
pos = file.indexOf("\n",pos)+1;
/*find the location of the next boundary marker
(marking the end of the upload file data)*/
int boundaryLocation = file.indexOf(boundary,pos)-4;
//upload file lies between pos and boundaryLocation
file = file.substring(pos,boundaryLocation);
//build the full path of the upload file
String fileName = new String(rootPath + directory +
saveFile);
//create File object to check for existence of file
File checkFile = new File(fileName);
if (checkFile.exists())
{
/*file exists, if OverWrite flag is off, give
message and abort*/
if (!overWrite.toLowerCase().equals("true"))
{
if (overWritePage.equals(""))
{
/*OverWrite HTML page URL not received, respond
with generic message*/
out.println("Sorry, file already exists.");
}
else
{
//redirect client to OverWrite HTML page
response.sendRedirect(overWritePage);
}
return;
}
}
/*create File object to check for existence of
Directory*/
File fileDir = new File(rootPath + directory);
if (!fileDir.exists())
{
//Directory doesn't exist, create it
fileDir.mkdirs();
}
//instantiate file output stream
fileOut = new FileOutputStream(fileName);
//write the string to the file as a byte array
fileOut.write(file.getBytes(),0,file.length());
if (successPage.equals(""))
{
/*success HTML page URL not received, respond with
eneric success message*/
out.println(successMessage);
out.println("File written to: " + fileName);
}
else
{
//redirect client to success HTML page
response.sendRedirect(successPage);
}
}
else //request is not multipart/form-data
{
//send error message to client
out.println("Request not multipart/form-data.");
}
}
catch(Exception e)
{
try
{
//print error message to standard out
System.out.println("Error in doPost: " + e);
//send error message to client
out.println("An unexpected error has occurred.");
out.println("Error description: " + e);
}
catch (Exception f) {}
}
finally
{
try
{
fileOut.close(); //close file output stream
}
catch (Exception f) {}
try
{
in.close(); //close input stream from client
}
catch (Exception f) {}
try
{
out.close(); //close output stream to client
}
catch (Exception f) {}
}
}
}
❽ jsp项目中涉及文件的上传和下载怎么实现
你是用什么框架，如果里面有struts的话可以用struts自带有上传下载的功能，只需要写代码就好了，如果需要加我987781070，如果没有用到struts可以用ajax实现，这个自己网络就好了，很多案例的！
❾ jsp 如何实现文件上传和下载功能
1.jsp页面
<s:form action="fileAction" namespace="/file" method="POST" enctype="multipart/form-data">
<!-- name为后台对应的参数名称 -->
<s:file name="files" label="file1"></s:file>
<s:file name="files" label="file2"></s:file>
<s:file name="files" label="file3"></s:file>
<s:submit value="提交" id="submitBut"></s:submit>
</s:form>
2.Action
//单个文件上传可以用 File files,String filesFileName,String filesContentType
//名称要与jsp中的name相同(三个变量都要生成get,set)
private File[] files;
// 要以File[]变量名开头
private String[] filesFileName;
// 要以File[]变量名开头
private String[] filesContentType;
private ServletContext servletContext;
//Action调用的上传文件方法
public String execute() {
ServletContext servletContext = ServletActionContext.getServletContext();
String dataDir = servletContext.getRealPath("/file/upload");
System.out.println(dataDir);
for (int i = 0; i < files.length; i++) {
File saveFile = new File(dataDir, filesFileName[i]);
files[i].renameTo(saveFile);
}
return "success";
}
3.配置上传文件临时文件夹(在struts.xml中配置)
<constant name="struts.multipart.saveDir" value="c:/temp"/>
文件下载
1.下载的url(到Action)
<a href="${pageContext.request.contextPath}/file/fileAction!down.action">下载</a>
2.struts.xml配置
<package name="file" namespace="/file" extends="struts-default">
<action name="fileAction" class="com.struts2.file.FileAction">
<!-- 下载文件配置 -->
<!--type 为 stream 应用 StreamResult 处理-->
<result name="down" type="stream">
<!--
不管实际类型，待下载文件 ContentType 统一指定为 application/octet-stream
默认为 text/plain
-->
<param name="contentType">application/octet-stream</param>
<!--
默认就是 inputStream，它将会指示 StreamResult 通过 inputName 属性值的 getter 方法，
比如这里就是 getInputStream() 来获取下载文件的内容，意味着你的 Action 要有这个方法
-->
<param name="inputName">inputStream</param>
<!--
默认为 inline(在线打开)，设置为 attachment 将会告诉浏览器下载该文件，filename 指定下载文
件保有存时的文件名，若未指定将会是以浏览的页面名作为文件名，如以 download.action 作为文件名，
这里使用的是动态文件名，${fileName}, 它将通过 Action 的 getFileName() 获得文件名
-->
<param name="contentDisposition">attachment;filename="${fileName}"</param>
<!-- 输出时缓冲区的大小 -->
<param name="bufferSize">4096</param>
</result>
</action>
</package>
3.Action
//Action调用的下载文件方法
public String down() {
return "down";
}
//获得下载文件的内容，可以直接读入一个物理文件或从数据库中获取内容
public InputStream getInputStream() throws Exception {
String dir = servletContext.getRealPath("/file/upload");
File file = new File(dir, "icon.png");
if (file.exists()) {
//下载文件
return new FileInputStream(file);
//和 Servlet 中不一样，这里我们不需对输出的中文转码为 ISO8859-1
//将内容(Struts2 文件下载测试)直接写入文件,下载的文件名必须是文本(txt)类型
//return new ByteArrayInputStream("Struts2 文件下载测试".getBytes());
}
return null;
}
// 对于配置中的 ${fileName}, 获得下载保存时的文件名
public String getFileName() {
String fileName ="图标.png";
try {
// 中文文件名也是需要转码为 ISO8859-1，否则乱码
return new String(fileName.getBytes(), "ISO8859-1");
} catch (UnsupportedEncodingException e) {
return "icon.png";
}
}