1-httpTest

package ServLet;

import javax.servlet.http.HttpServlet;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpTest  {
    public static void main(String[] args) {
        try {
            String url="http://localhost:8080/javaweb_test_war_exploded//ajax";
            URL connectionUrl = new URL(url);

            HttpURLConnection urlConnection = (HttpURLConnection) connectionUrl.openConnection();
            urlConnection.setRequestProperty("appkey","123456");

            InputStream inputStream =urlConnection.getInputStream();
            InputStreamReader reader = new InputStreamReader(inputStream);
            BufferedReader in = new BufferedReader(reader);
            String line;
            String result = "";
            while ((line = in.readLine()) !=null){
                result += line;
            }
            System.out.println(result);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

2-ajaxtest.java

 package ServLet;

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;


@WebServlet("/ajax")
public class ajaxTest extends HttpServlet {
    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("请求成功");
        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset-utf-8");
        resp.setHeader("content-type","text/html;charset=utf-8");
        resp.getWriter().write("接受成功了");

        String appkey = req.getHeader("appkey");
        if (appkey == null){
            resp.getWriter().write("请求不合法");
            return;
        }

        String json = "{\"name\":\"张三\",\"age\":18\"}";
        resp.getWriter().write(json);

    }
}