$.post()与服务端简单通信

怼烎@ 2022-06-01 03:49 166阅读 0赞

当首页index.js加载完毕的时候，ajax向服务端发送一个请求，服务端就收到请求作出响应。  
前端页面$.post(url,param,fn,type)

<head>
        <script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-1.4.4.min.js"></script>
        <script type="text/javascript"> $(function () { var url = "${pageContext.request.contextPath}/jsonServlet"; param = { "test": "testing data"};//json格式字符串 $.post(url, param, function (data) { alert(data.rtn); },"json"); }); </script>
    </head>
    <html>
    <head>
        <title>Title</title>
    </head>
    <body>
    
    </body>
    </html>

服务端servlet

@WebServlet(name = "jsonServlet", urlPatterns = "/jsonServlet")
    public class JsonServlet extends HttpServlet { 
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("doPost");
            System.out.println(request.getParameter("test"));//拿到了前台json格式的参数，取出参数值
            response.getWriter().print("{\"rtn\":\"ok\"}");
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("doGet");
            System.out.println(request.getParameter("test"));
        }
    }

结果

doPost
    testing data

![这里写图片描述][SouthEast]

总结：  
jsp页面加载完毕后，一post的方式发送了异步请求，其中请求参数是json格式的，可以看到服务端的`request.getParameter("test")`将前台传来的json格式的字符串进行了解析，并拿到了传递过来的参数。最后服务端向页面写会一段json格式的字符串。

[SouthEast]: /images/20220601/3a69ee87e3144aaa9b215dd164c8e712.png