檔案上與下載下傳
- 案例需求分析與步驟
- 下載下傳頁面的代碼實作
- 檔案下載下傳的Servlet代碼部分
- 中文檔案名的工具類
案例需求分析與步驟
Servlet的檔案下載下傳案例案例需求分析與步驟下載下傳頁面的代碼實作檔案下載下傳的Servlet代碼部分中文檔案名的工具類 下載下傳頁面的代碼實作
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<a href="/08_response/downloadServlet?filename=素描1.jpg">素描風景</a>
<a href="/08_response/downloadServlet?filename=夏天的風.mp3">夏天的風</a>
</body>
</html>
檔案下載下傳的Servlet代碼部分
package pers.cb.web.download;
import pers.cb.web.utils.DownLoadUtils;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
@WebServlet("/downloadServlet")
public class DownloadServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.擷取請求參數,檔案名稱
String filename = request.getParameter("filename");
//2.使用位元組輸入流加載檔案進記憶體
//2.1找到檔案伺服器路徑
ServletContext servletContext = this.getServletContext();
//判斷檔案類型來找到檔案伺服器路徑
String realPath = null;
if (filename.endsWith(".jpg"))
{
realPath = servletContext.getRealPath("/img/" + filename);
}
if (filename.endsWith(".mp3"))
{
realPath = servletContext.getRealPath("/music/" + filename);
}
System.out.println(realPath);
//2.2用位元組流關聯
FileInputStream fis = new FileInputStream(realPath);
//3.設定response的響應頭
//3.1設定響應頭類型:content-type
String mimeType = servletContext.getMimeType(filename);//擷取檔案的mime類型
response.setHeader("content-type",mimeType);
//response.setContentType("text/html;charset=utf-8");
//解決中文檔案名問題
//1.擷取user-agent請求頭
String agent = request.getHeader("user-agent");
//2.使用工具類方法編碼檔案名即可
filename = DownLoadUtils.getFileName(agent, filename);
//3.2設定響應頭打開方式
response.setHeader("content-disposition","attachment;filename=" + filename);
//4.将輸入流的資料寫出到輸出流中
ServletOutputStream sos = response.getOutputStream();
byte[] bytes = new byte[1024 * 8];
int len = 0;
while((len = fis.read(bytes)) != -1)
{
sos.write(bytes,0,len);
}
fis.close();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
中文檔案名的工具類
package pers.cb.web.utils;
import sun.misc.BASE64Encoder;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
public class DownLoadUtils {
public static String getFileName(String agent,String filename) throws UnsupportedEncodingException {
if (agent.contains("MSIE"))
{
// IE浏覽器
filename = URLEncoder.encode(filename,"utf-8");
filename = filename.replace("+"," ");
} else if (agent.contains("Firefox"))
{
// 火狐浏覽器
BASE64Encoder base64Encoder = new BASE64Encoder();
filename = "=?utf-8?B?" + base64Encoder.encode(filename.getBytes("utf-8")) + "?=";
} else{
// 其他浏覽器
filename = URLEncoder.encode(filename,"utf-8");
}
return filename;
}
}
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