Qt与java web通过数据库实现数据展示同步

程序运行截图如下：

逻辑：

Qt修改数据库，java通过Hibernate读取数据库，然后显示，前端通过计时器实现不点刷新就能获取数据！

Qt源码如下：

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QSqlDatabase>

QT_BEGIN_NAMESPACE
class QSqlQuery;
QT_END_NAMESPACE

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

protected slots:
    void textChanged(QString text);

private:
    Ui::Widget *ui;

    QSqlDatabase m_db;
    QSqlQuery *m_query;
};

#endif // WIDGET_H

main.cpp

#include "widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>
#include <QSqlQuery>
#include <QVariant>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setWindowTitle("CSDN IT1995");

    m_db = QSqlDatabase::addDatabase("QMYSQL");
    m_db.setHostName("localhost");
    m_db.setDatabaseName("candjavadb");
    m_db.setUserName("root");
    m_db.setPassword("root");

    if(m_db.open()){

        qDebug()<< "open success!";
    }
    else{

        qDebug()<< "open fail";
    }

    m_query = new QSqlQuery(m_db);
    connect(ui->lineEdit, SIGNAL(textChanged(QString)), this, SLOT(textChanged(QString)));
}

Widget::~Widget()
{
    delete ui;
}

void Widget::textChanged(QString text)
{
    m_query->prepare("update test set data=? where id=?");
    m_query->addBindValue(text);
    m_query->addBindValue("0");
    m_query->exec();
}

java相关代码：

先是前端：

db.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>数据库操作</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
	
	<script src="jquery/jquery.js"></script>
	<script src="bootstrap/js/bootstrap.min.js"></script>
	<script src="jquery/jquery.timer.js"></script>
	
<script >
	
	function trace( msg ){	
	
		try{ 
			console.log(msg); 
		} 
		catch(err){ }
	}
	
	function onQuery()
	{
		jQuery.ajax({			 
			method: "GET",			 
			url: "servlet/WebDB",
			success: function(data, textStatus, jqXHR)
			{
				$("#userCount").html(data);
			},
			error: function( jqXHR, textStatus, errorThrown){
				trace( "error: " + errorThrown );	
			}
		});
		
	}
	
	// 页面加载后的初始化工作
	$(document).ready( function(){
		 
		 var timerId = $.timer(1000, onQuery, false);
	});
		
	</script>

  </head>
  
  <body>
    <div class="container">
  		<p> 区域负荷 <span id="userCount"> 0 </span> </p>
  	</div>
  </body>
  </body>
</html>

servlet/WebDB中只修改了doGet方法：

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

		float data = new RegionalLoad().count();
		String replyText = String.valueOf(data);
		
		response.setContentType("text/plain");
		response.setCharacterEncoding("UTF-8");
		PrintWriter out = response.getWriter();
		out.write(replyText);
		out.close();
	}

RegionalLoad.java

package my;
import my.db.*;
import org.hibernate.Session;

public class RegionalLoad {

	public float count(){
		
		Session dbss = null;
		float floatData = 0.0f;
		
		try{
			
			dbss = HibernateSessionFactory.getSession();
			Integer rowID = new Integer(0);
			Test row = (Test)dbss.get(Test.class, rowID);
			
			if(row == null){
				
				System.out.println("找不到记录！");
			}
			else{
				
				floatData = row.getData();
			}
		}
		catch(Exception e){
			
			System.out.println("出错：" + e.getMessage());
			e.printStackTrace();
		}
		finally{
			
			if(dbss != null)
				dbss.close();
		}
		
		return floatData;
	}
}

Qt与java web通过数据库实现数据展示同步

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