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();
	}
}