servlet响应头

package com.lanou;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet(urlPatterns = "/four")
public class FourthServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //http协议中,把每一次网络请求分成两部分
        //1.请求 request
        //2.响应,response


        //设置响应内容的字符集和内容类型
        resp.setHeader("Content-Type","text/html;charset=utf-8");
		//在返回响应内容之前,要设置响应头image/png application/json等
		//前端收到数据后,会根据该设置做不同的处理  
        PrintWriter writer = resp.getWriter();
        writer.write("<h1>Hello World 你好 世界</h1>");
        writer.close();
    }
}