javaweb中的文件下载
package cn.itcast.day06.web.servlet;import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class DownloadServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 实现防盗链功能
// 获得 referer 头 用于说明来访者来自哪里
String referer = request.getHeader("referer");
if(referer==null || !referer.startsWith("http://localhost")) {
// 是盗链者
response.sendRedirect("/day06/index.jsp");
return ;
}
// 解决response中文乱码问题
response.setContentType("text/html;charset=utf-8");// 设置消息体的编码
// 通过 http 协议 发送的http响应消息头 不能出现中文 中文必须要经过url编码
String filename = URLEncoder.encode("美女.jpg", "utf-8");
// 通知浏览器以下载的方式读取资源
response.setHeader("content-disposition", "attachment;filename="+filename);
// 读取图片数据 发给ie浏览器
String webPath = "/download/美女.jpg";// 相当于当前web应用的path
ServletContext servletContext = super.getServletContext();
InputStream in = servletContext.getResourceAsStream(webPath);
OutputStream out = response.getOutputStream();
int len;
byte[] buffer = new byte;
while((len=in.read(buffer))!=-1)
out.write(buffer, 0, len);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
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