一、筆記
2.
3. 文件上傳步驟:
3.1 一些方法
3.2
文件下載:
1.
1.1
二、擼代碼
文件上傳代碼:
servlet
package cn.lixuquan.fileUPload;
/**
* 需求:
* 學習文件上傳
*/
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.UUID;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class FileUpLoad
*/
@WebServlet("/FileUpLoad")
public class FileUpLoad extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//響應中文亂碼問題
response.setContentType("text/html;charset=utf-8");
//1.創建文件上傳工廠對象
DiskFileItemFactory factory = new DiskFileItemFactory();
//1.1通過工廠對象設置臨時文件
File f = new File("d:\\Temp");
if(!f.exists())
{
f.mkdirs();
}
factory.setRepository(f);
factory.setSizeThreshold(1024*1024);
//2.創建解析器對象
ServletFileUpload fileUpload = new ServletFileUpload(factory);
//2.1設置字符編碼
fileUpload.setHeaderEncoding("utf-8"); //處理上傳普通字段,文件名稱的中文亂碼問題
//3.解析請求對象
try {
List<FileItem> fileItems = fileUpload.parseRequest(request);
//開始遍歷這個表單項
for(FileItem fileitem: fileItems)
{
boolean flag = fileitem.isFormField();
if(flag)
{
//普通表單項
String name = fileitem.getFieldName();
if("username".equals(name))
{
if(!fileitem.getString().equals(""))
{
String value = fileitem.getString("utf-8");
response.getWriter().print("上傳者:"+value+"<br>");
}
}
}
else
{
//文件上傳的表單項
String filename = fileitem.getName();
//處理文件名稱包含路徑的問題
if(filename != null && !filename.equals(""))
{
response.getWriter().print("上傳的文件名稱是:"+filename+"<br>");
filename = filename.substring(filename.lastIndexOf("\\")+1);
//處理上傳文件同名的問題
filename = UUID.randomUUID()+"_"+filename;
//服務器端 創建同名的文件
String webPath = "/upload/";
//把文件名稱和服務端的文件組合在一起
String filePath = getServletContext().getRealPath(webPath+filename);
//創建文件夾
File file = new File(filePath);
file.getParentFile().mkdirs();
file.createNewFile();
//獲取文件的字節輸入流
InputStream is = fileitem.getInputStream();
//獲取一個輸出流
FileOutputStream os = new FileOutputStream(file);
int len = 0;
byte[] buffer = new byte[1024];
while((len=is.read(buffer)) > 0)
{
os.write(buffer, 0, len);
}
//關閉流
os.close();
is.close();
//刪除臨時文件
fileitem.delete();
response.getWriter().print("文件上傳成功"+"<br>");
}
}
}
} catch (FileUploadException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>文件上傳</title>
</head>
<body>
<form action="/servletPractice/FileUpLoad" method="post" enctype="multipart/form-data">
學 號:<input type="text" name="username" /><br>
密 碼:<input type="password" name="password"/><br>
文件上傳 :<input type="file" name="file" /><br>
<input type="submit" value="提交">
</form>
</body>
</html>
注意: 表單裏必須加enctype=“multipart/form-data”,不然上傳的只是文件名,沒有內容。
文件下載代碼
servlet
package cn.lixuquan.fileUPload;
/**
* 需求:文件下載
*/
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
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#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//1.處理響應中文亂碼問題
response.setContentType("text/html;charset=utf-8");
//2.獲取下載的文件名稱,由於下載和上傳的fileupload的jar包沒有一毛錢關係,所以使用request的一些相關方法
String filename = request.getParameter("filename");
//處理get請求的中文亂碼問題
filename = new String(filename.getBytes("iso-8859-1"),"utf-8");
//3.獲取文件的mime類型(這裏你可以簡單的理解爲文件的後綴名)
String fileType = getServletContext().getMimeType(filename);
String name=DownUtils.filenameEncoding(filename, request);
//4.設置兩個頭
response.addHeader("Content-Type",fileType);
response.addHeader("Content-Disposition", "attachment;filename="+name);
//5.文件的下載
String folder = "/download/";
//5.1獲取文件的字節輸入流
InputStream is = getServletContext().getResourceAsStream(folder+filename);
//5.2獲取文件的字節輸出流
OutputStream os = response.getOutputStream();
int len = 0;
byte[] buffer = new byte[1024];
while((len=is.read(buffer)) != -1)
{
os.write(buffer, 0, len);
}
//關閉流
os.close();
is.close();
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
jsp代碼:
<%@page import="java.net.URLEncoder"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>文件下載</title>
</head>
<body>
<a href="downloadServlet?filename=1.jpg">文件下載</a>
<br>
<a href="downloadServlet?filename美女.jpg">文件下載</a>
</body>
</html>
DownUtil代碼
package com.zch.upload;
import sun.misc.*;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import javax.servlet.http.HttpServletRequest;
public class DownUtils {
public static String filenameEncoding(String filename, HttpServletRequest request) throws UnsupportedEncodingException {
// 獲得請求頭中的User-Agent
String agent = request.getHeader("User-Agent");
// 根據不同的客戶端進行不同的編碼
if (agent.contains("MSIE")) {
// IE瀏覽器
filename = URLEncoder.encode(filename, "utf-8");
} else if (agent.contains("Firefox")) {
// 火狐瀏覽器
BASE64Encoder base64Encoder = new BASE64Encoder();
filename = "=?utf-8?B?" + base64Encoder.encode(filename.getBytes("utf-8")) + "?=";
} else {
// 其它瀏覽器
filename = URLEncoder.encode(filename, "utf-8");
}
return filename;
}
}
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