Question

首先感谢您花时间在我的问题上。

这里我想做的事情：当我的jsp页面加载时，我想从我的servlet中获取一个值来设置我的按钮的实际状态和滑块值的实际状态。然后在我的页面上更新，我想改变它的价值。我已经可以将JSP页面值传递给我的servlet，但我仍然坚持将值从servlet传递到jsp页面。

以下是一些帮助

的代码

此致

JSP FILE

<!--<!--DOCTYPE html -->

<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="./resources/css/jquery.mobile-1.4.2.css">
<script src="./resources/script/jquery-1.11.0.js"></script>
<script src="./resources/script/myJquery.js"></script>
<script src="./resources/script/jquery.mobile-1.4.2.js"></script>
</head>
<body>


    <!-- RDC SUB WINDOW LIVING -->
    <div data-role="page" ID="LIVING">
        <div data-role="header">
            <a href="#RDC"
                class="ui-btn ui-corner-all ui-shadow ui-icon-home ui-btn-icon-left">HOME</a>
            <h1>LIVING ROOM</h1>
        </div>

        <div data-role="main" class="ui-content">
            <div data-role="collapsible">
                <h1>CELLING: LIGHT</h1>
                <div class="containing-element">
                    <img src="./resources/images/light-on.png" alt="LIGHT-ON"
                        class="ui-li-icon"> <br> <select id="tLight"
                        name="tLight" data-role="slider">
                        <option value="off">Off</option>
                        <option value="on">On</option>
                    </select> <input type="range" name="tDimmer" id="tDimmer" value="0" min="0"
                        max="100" data-popup-enabled="true">
                </div>

            </div>
        </div>

        <div data-role="footer">
            <h1></h1>
        </div>
    </div>

AJAX代码

//Living room Server $POST
$(document).ready(function() {

    $(function Dimmer() {
        $("#tDimmer").change(function() {
            $.post("MyServlet", {
                mLivingDimmer : $("#tDimmer").val()
            });
        });
    });
    $(function Light() {
        $("#tLight").change(function() {
            $.post("MyServlet", {
                mLivingLight : $("#tLight").val()
            });
        });
    });
});

SERVLET CODE：

package com.linux;

import java.io.IOException;
import java.io.PrintWriter;

import com.pi4j.io.gpio.GpioController;
import com.pi4j.io.gpio.GpioFactory;
import com.pi4j.io.gpio.GpioPinDigitalOutput;
import com.pi4j.io.gpio.PinState;
import com.pi4j.io.gpio.RaspiPin;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


//@WebServlet("/MyServlet")
public class MyServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    //GpioController gpio;
    //GpioPinDigitalOutput mLight;
    String LightState = "on";
    String DimmerValue = "25";

    public MyServlet() {
                super();

    }


    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }


    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        System.out.println("LivingLight = "+request.getParameter("mLivingLight"));  
        System.out.println("LivingDimmer = "+request.getParameter("mLivingDimmer"));    
    }
}

Answer 1

如果在命令提示符下或单击批处理文件启动它，

System.out.println()将打印到控制台，即打印到Tomcat的控制台（或任何servlet容器）。您想打印到响应。所以你需要：

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    PrintWriter out = response.getWriter();
    out.write("LivingLight = "+request.getParameter("mLivingLight"));  
    out.write("LivingDimmer = "+request.getParameter("mLivingDimmer"));    
}

然后在您的Ajax中，您需要一个成功函数，您将使用字符串操作解析从服务器返回的响应：

             ...,
             success : function(data)
             {
                //Parse data
             },
             ....

使用ajax将值从servlet返回到jsp页面

1 个答案: