檔案上傳的三種方法 1servlet方式
今天突然想起來檔案上傳,竟然不會了,趕緊拿出來學習總結下。
**1.原始的servlet檔案上傳下載
2.Struts2框架的檔案上傳
3.Spring-Mvc框架的檔案上傳**
1.原始的servlet檔案上傳下載
簡單說下流程
1. 開發form表單,input type=”file”的控制元件,修改form表單的enctype=”multipart/form-data”
2. 後臺servlet,如果是servlet3.o直接在servlet類前面做一個@MultipartConfig註解 ,如果此時是3.0之前版本,採用apache下面的開源專案commonupload和commonio來做檔案上傳。
3. doPost方法獲取檔案,寫到伺服器的某個目錄。
怎麼解析上傳檔案的名字呢?
用firebug看到了檔案上傳的請求頭部有:
content-length:內容長度
Content-type: multipart/form-data; boundary=—————————217601275726149(檔案內容分隔符)
Post內容:
—————————217601275726149
Content-Disposition: form-data; name=”ff”; filename=”student.sql” Content-Type: application/octet-stream
我們可以用boundary分割得到第一部分,然後解析字串,得到filename
具體程式碼下面貼
Servlet2.5版本檔案上傳(瞭解,現在都用3.0的吧!):
http//jakarta.apache.org/commons/fileupload------commonupload和commonio兩個jar包
核心上傳程式碼
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(1024*1024*20);
factory.setRepository(new File(request.getRealPath("/" )));
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setSizeMax(1024*1024*20);
List items = upload.parseRequest(request);
for(Iterator it=items.iterator(); it.hasNext();){
FileItem item = (FileItem)it.next();
//判斷是否為表單域
if(item.isFormField()){
String name = item.getFieldName();
String value = item.getString("UTF-8");
out.println("name=value:"+"name="+name+",value="+value);
}else {
//獲取檔案域名
String fieldName = item.getFieldName();
//獲取檔名
String fileName = item.getName();
//獲得檔案型別
String contentType = item.getContentType();
FileOutputStream fos = new FileOutputStream(request.getRealPath("/") + System.currentTimeMillis()+
fileName.subSequence(fileName.indexOf("."), fileName.length()));
if(item.isInMemory()){
fos.write(item.get());
}else {
InputStream is = item.getInputStream();
byte [] buffer = new byte[1024];
int len;
while((len = is.read(buffer)) >1){
fos.write(buffer, 0, len);
}
is.close();
fos.close();
item.delete();//臨時檔案刪除要在流關閉之後,不然刪除不掉,流沒有完全關閉的話,會出現佔用資源windows系統的問題
}
}
}
Servlet3.0檔案上傳:
uploadservlet
package com.action;
import java.io.IOException;
import java.util.Collection;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
/**
* Servlet implementation class uploadServlet
*/
@WebServlet("/upload")
//要上傳檔案到哪個資料夾
@MultipartConfig(location="d:/upload")
public class uploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public uploadServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
//單,多檔案上傳通用
Collection<Part> parts = request.getParts();// 多檔案上傳 獲取part物件 part物件儲存檔案內容 返回集合型別
for(Part part:parts){
//固定寫法
String value=part.getHeader("Content-Disposition");//提取請求頭
int begin = value.indexOf("filename=");
begin=begin+10;
int end = value.lastIndexOf("\"");
String name=value.substring(begin, end);
//給檔名後追加數字
Date date=new Date();//java.util.Date
long time=date.getTime();//獲取1970年到現在的毫秒數
name=name.replace(".",time+".");
part.write(name);
part.delete();//刪除臨時檔案
}
/*請求頭 根據它找到上傳檔名
* Content-Disposition: form-data; name="upload"; filename="servlet2.docx"
Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document
*/
}
}
upload.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<%
//設定頁面響應格式
//response.setContentType("application/vnd.ms-excel");
%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<script type="text/javascript" src="js/jquery-1.8.3.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("#submitBtn").click(function(){
var file=$("#upload").val();
var reg=/txt$/;
if(!reg.test(file)){
alert("上傳檔案格式不正確");
return false;
}
});
});
</script>
<body>
<h2>檔案上傳</h2>
<form action="upload" method="post" enctype="multipart/form-data">
上傳<input type="file" name="upload" id="upload">
<!--
上傳<input type="file" name="upload">
上傳<input type="file" name="upload">
-->
<input type="submit" value="上傳" id="submitBtn" >
</form>
<a href="servlet2.docx">下</a>
<a href="downloadServlet">下載</a>
</body>
</html>
servlet檔案下載
Response設定contenttype.
response.setContentType(“application/octet-stream”);Response設定響應頭Content-Dispostion
response.setHeader(“Content-Disposition”, “attachment;filename=\”aa.xlsx\”“);
attachment:表示檔案輸出流會以附件的方式下載。
downloadservlet
package com.action;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class downloadServlet
*/
@WebServlet("/downloadServlet")
public class downloadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public downloadServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("application/octet-stream");//設定響應格式為任何位元組流型別
//設定響應頭 attachment表示檔案輸出流會以附件的方式下載
response.setHeader("Content-Disposition", "attachment;filename=\"zyt.doc\"");
OutputStream out = response.getOutputStream();
String file="C:/Users/Oracle/Desktop/servlet2.docx";
InputStream in =new FileInputStream(file);
//把in讀取到的要下載的檔案的內容 寫入到out 給瀏覽器
byte b[]=new byte[1024];//緩衝區
int len=0;//每一次讀取的位元組長度
while((len=in.read(b))!=-1){
out.write(b, 0, len);
}
out.close();
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
}
download.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<%
response.setContentType("application/msword");
%>
<body>
</body>
</html>
另外兩種方式下一篇說吧,我個人就不愛看特別多頁的文章