使用content-type响应头(服务器发送内容的类型和编码类型)
package cn.itcast.web.http;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class Demo3 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//通知浏览器打开文件的类型response.setHeader("content-type","image/jpeg");//response.setHeader("content-type","application/msword");File file = new File("d:\\a.jpg");InputStream is = new FileInputStream(file);OutputStream os = response.getOutputStream();//对应浏览器的输出流byte[] buf = new byte[1024];int len = 0;while( (len=is.read(buf))>0 ){os.write(buf,0,len);}is.close();os.close();}}