JAVA里面读取PostgreSQL数据库最近80条温度检测记录，并用Highcharts展示在网站上

效果如下：

花了2天时间处理了服务器端的GET处理部分，和前端HTML部分。

难点(1)：series[0]["data"][jjj]=parseFloat(arr_temp[jjj]);首先series[0]的[0]是不能省掉的，因为采用的这个是多曲线展示，要展示的是第一条曲线。其次，这个是浮点型，直接把整型赋值给它是不行的。

难点(2)：sql = "select * from ut_ut_detect_value where pointdetect_assit_infor<>'Randon Value Added' order by recordsn desc limit 80"; 读取PostgreSQL数据库里面最新的80条温度记录，而且不能包含AWS的EC2给该表添加的随机数的部分。

难点（3）：数据准备好后再调用hightcharts显示，其实很简单，把数据显示部分打包成一个函数。在准备数据的函数里面再数据准备好后后再调用这个函数。不需要什么延时的处理。如下：

$.get("http://pptexpert.cn/ServeletQ/TestSV",function(data,status){ str1 = data; count = 1; test_display(); // do { curDate = new Date(); } // while(curDate-date < 200); // alert("Data is ready! Click the (2) to display" ); });

要点（4）：使用网站上的PS在线服务，用来确定图片上某点的颜色值。http://www.uupoop.com/ps/，方法参见：点这儿！

要点（5）：UltraEdit自身带有HTML页面的按钮、前景颜色、背景颜色的快捷设置，很方便！

源代码：

服务器端：

package com.qxd; import java.io.IOException; import java.io.PrintWriter; import java.text.SimpleDateFormat; import java.util.Date; 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.sql.DriverManager; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; /** * Servlet implementation class TestSV */ @WebServlet("/TestSV") public class TestSV extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public TestSV() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub System.out.println("Entry of the test GET part =============" ); SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); String ssString = df.format(new Date()); PrintWriter out = response.getWriter(); out.print("Reply from server Servel!"); out.print("Reply on 20170109!"); System.out.println(ssString); out.print(ssString); System.out.println("Exit from the test GET part ************ " ); System.out.println("-------- PostgreSQL " + "JDBC Connection Testing ------------"); try { Class.forName("org.postgresql.Driver"); } catch (ClassNotFoundException e) { System.out.println("Where is your PostgreSQL JDBC Driver? " + "Include in your library path!"); e.printStackTrace(); return; } System.out.println("PostgreSQL JDBC Driver Registered!"); Connection connection = null; try { connection = DriverManager.getConnection( "jdbc:postgresql://180.76.147.172:5432/lportal", "username", "password"); } catch (SQLException e) { System.out.println("Connection Failed! Check output console"); e.printStackTrace(); return; } if (connection != null) { System.out.println("You made it, take control your database now!"); } else { System.out.println("Failed to make connection!"); } String sql = "select * from ut_ut_detect_value where pointdetect_assit_infor<>'Randon Value Added' order by recordsn desc limit 80"; Statement stmt = null; try { stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } ResultSet rs = null; try { rs = stmt.executeQuery(sql); } catch (SQLException e2) { // TODO Auto-generated catch block e2.printStackTrace(); } try { while (rs.next()) { System.out.print(rs.getString(1)); out.print(rs.getString(1)); System.out.print(" "); out.print(" "); System.out.println(rs.getString(10)); out.print(rs.getString(10)); System.out.print(" "); out.print(" "); System.out.println(rs.getString(11)); out.print(rs.getString(11)); System.out.print(" "); out.print(" "); System.out.println(rs.getString(12)); out.print(rs.getString(12)); out.print(" "); } } catch (SQLException e2) { // TODO Auto-generated catch block e2.printStackTrace(); } try { rs.close(); } catch (SQLException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } try { stmt.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { connection.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } out.close(); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }

HTML端：

<!DOCTYPE html> <html> <head> <title>David Room Temperature</title> <script type="text/javascript" src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script> <script src="http://code.highcharts.com/highcharts.js"></script> <div id="container" style="width: 1000px; height: 800px; margin: 0 auto"></div> <script> $(document).ready(function(){ var str1 ="blank string"; var str2 ="blank string"; var str3 = ""; var str4 = ""; var arr = new Array(); var arr_temp = new Array(); var arr_date = new Array(); var value = 10.0; var resistance =10.0; var B = 3975.0; var temperature=20.0; var date = new Date(); var curDate = null; $.get("http://pptexpert.cn/ServeletQ/TestSV",function(data,status){ str1 = data; do { curDate = new Date(); } while(curDate-date < 20); // alert("Data is ready! Click the (2) to display" ); }); $("button2").click(function(){ str2 = str1; str3 = str2.substring(62); arr = str3.split(" "); for (var i=79;i>=0;i--) { arr_temp[i] = arr[4*(79-i)+1] ; arr_date[i] = arr[4*(79-i)+2] ; } var title = { text: 'David Room Temperature (\xB0C)' }; var subtitle = { text: 'Source: pptexpert.cn' }; var xAxis = { categories: ['“ª‘¬', '∂˛‘¬', '»˝‘¬', 'Àƒ‘¬', 'ŒÂ‘¬', '¡˘‘¬' ,'∆fl‘¬', '∞À‘¬', 'æ≈‘¬', 'Æ‘¬', 'Æ“ª‘¬', 'Æ∂˛‘¬','“ª‘¬', '∂˛‘¬', '»˝‘¬', 'Àƒ‘¬', 'ŒÂ‘¬', '¡˘‘¬' ,'∆fl‘¬', '∞À‘¬', 'æ≈‘¬', 'Æ‘¬', 'Æ“ª‘¬', 'Æ∂˛‘¬'] }; for (var jj=0;jj<=79;jj++) { xAxis.categories[jj]=arr_date[jj].substring(0,16); } ; var yAxis = { min:0, title: { text: 'Temperature in David room (\xB0C)' }, plotLines: [{ value: 0, width: 1, color: '#808080' }] }; var tooltip = { valueSuffix: '\xB0C' } var legend = { layout: 'vertical', align: 'right', verticalAlign: 'middle', borderWidth: 0 }; var ccc1 = arr_temp[0]; var series = [ { name: 'David Home', data: [7, 6.9, 9.5, 14.5, 18.2, 21.5, 25.2, 26.5, 23.3, 18.3, 13.9, 9.6,7, 6.9, 9.5, 14.5, 18.2, 21.5, 25.2, 26.5, 23.3, 18.3, 13.9, 9.6] }, ]; series[0]["data"][0]=100; var fff = parseFloat(arr_temp[0]); for (var jjj=0;jjj<=79;jjj++) { value = parseFloat(arr_temp[jjj]); // alert("value" + value ); resistance = (1023-value)*10000/value; // alert("resistance" + resistance ); temperature = 1.0/(Math.log(resistance/10000.0)/B+1.0/298.15)-273.15; temperature = Math.round(temperature*100)/100; // alert("temperature" + temperature ); series[0]["data"][jjj]=temperature; } ; // series[0]["data"][0]=0.0; var json = {}; json.title = title; json.subtitle = subtitle; json.xAxis = xAxis; json.yAxis = yAxis; json.tooltip = tooltip; json.legend = legend; json.series = series; $('#container').highcharts(json); }); }); </script> </head> <body> <div style="text-align: center"><div style="margin:3 auto;width:193px;align="center""> </div><div style="background-color: #7bb4eb"><b><div style="margin:3 auto;width:200px;"></div><button2 type="button" align="center">Click Here!</button2></b></div> </div> </body> </html>