一、
1）、response獲得的流不需要手動關閉，Tomcat容器會幫你自動關閉
2）、getWriter和getOutputStream不能同時調用

//error
package com.itheima.content;import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class ErrorServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.getWriter();//這兩行代碼先后順序一變化，頁面的提示也會相應變化response.getOutputStream();}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

會報錯：

3）、response有緩沖區，并且緩沖區有大小默認是8K