我正在尝试使用 Java 文件从数据库检索值并将其存储到 HashMap。请找到以下代码(Sample.java):
import java.sql.*;
import java.util.HashMap;
public class Sample {
static Connection conn;
static PreparedStatement stmt;
static ResultSet rs;
String sql;
static String project="Project1";
public static HashMap< String, String> map = new HashMap< String, String>();
public static void main(String[] args) {
try{
Class.forName("com.mysql.jdbc.Driver");
conn=DriverManager.getConnection("jdbc:mysql://localhost:3309/graphvalue","root","root");
stmt=conn.prepareStatement("select * from TestCase where ProjectName= ?");
stmt.setString(1,project);
rs=stmt.executeQuery();
while(rs.next())
{
System.out.println(rs.getString(1)+" "+rs.getInt(2)+" "+rs.getInt(3)+" "+rs.getInt(4)+" "+rs.getInt(5));
map.put("ProjectName", rs.getString(1));
map.put("Total TestCase", String.valueOf(rs.getInt(2)));
map.put("TestCase Executed", String.valueOf(rs.getInt(3)));
map.put("Failed TestCase", String.valueOf(rs.getInt(4)));
map.put("TestCase Not Executed", String.valueOf(rs.getInt(5)));
System.out.println("ProjectName "+map.get("ProjectName"));
}
conn.close();
}
catch(Exception e)
{ System.out.println(e);}
}
}
请找到我从数据库检索的以下数据:
ProjectName TotalTestCase TestCaseExecuted TestCaseFailed TestCaseNotExecuted
Project1 50 30 8 20
我想将此值传递给 Javascript，以便我能够使用这些值绘制图表。请在下面找到我的 HTML/Javascript 代码 (test.html):
<html>
<head>
</head>
<body>
<select id="ChartType" name="ChartType" onchange="drawChart()">
<option value = "PieChart">Select Chart Type
<option value="PieChart">PieChart
<option value="Histogram">Histogram
<option value="LineChart">LineChart
<option value="BarChart">BarChart
</select>
<div id="chart_div" style="border: solid 2px #000000;"></div>
<p id="demo"></p>
<p id="demo1"></p>
<script type="text/javascript" src="https://www.google.com/jsapi"></script>
<script type="text/javascript">
var row = [];
var temp;
var stri;
google.load('visualization', '1.0', {'packages':['corechart']});
google.setOnLoadCallback(getValues);
function getValues() {
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
stri = xmlhttp.responseText;
drawChart();
}
};
xmlhttp.open("GET", "sample.java", true);
xmlhttp.send();
}
function drawChart() {
var data = new google.visualization.DataTable();
str = stri.split(",");
// How to call the value from java file so that I will be able to draw the below graph by passing the value.
data.addRows(row);
var a = document.getElementById("ChartType").value;
document.getElementById("demo1").innerHTML = "You selected: " + a;
var options = {'title':'How Much Pizza I Ate Last Night',
'width':400,
'height':300
};
var chart = new google.visualization[document.getElementById("ChartType").value](document.getElementById('chart_div'));
chart.draw(data, options);
}
</script>
</body>
</html>
请告诉我如何继续或是否有人有任何其他示例。请与我分享。谢谢
最佳答案
您可以 convert your map to
的服务JSON。而不是这个 HelloWorld 类，您可以将其转换为返回此 `JSONimport java.sql.*; import java.util.HashMap; public class Sample { static Connection conn; static PreparedStatement stmt; static ResultSet rs; String sql; static String project = "Project1"; public static HashMap < String, String > map = new HashMap < String, String > (); //Notice how your main class is now converted into a service public static String getProjects() { try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection("jdbc:mysql://localhost:3309/graphvalue", "root", "root"); stmt = conn.prepareStatement("select * from TestCase where ProjectName= ?"); stmt.setString(1, project); rs = stmt.executeQuery(); while (rs.next()) { System.out.println(rs.getString(1) + " " + rs.getInt(2) + " " + rs.getInt(3) + " " + rs.getInt(4) + " " + rs.getInt(5)); map.put("ProjectName", rs.getString(1)); map.put("Total TestCase", String.valueOf(rs.getInt(2))); map.put("TestCase Executed", String.valueOf(rs.getInt(3))); map.put("Failed TestCase", String.valueOf(rs.getInt(4))); map.put("TestCase Not Executed", String.valueOf(rs.getInt(5))); System.out.println("ProjectName " + map.get("ProjectName")); /*______________ NEW CODE ______________*/ JSONObject resultMap = new JSONObject(map); return resultMap.toString(); } } catch (Exception e) { System.out.println(e); } finally { conn.close(); } return ""; } }现在将您的
test.html转换为test.jsp并调用该服务 我们在上一步中创建并输出结果JSON到 JavaScript 变量中。测试.jsp
<%@page import="com.path.to.Sample"%> <html> <head> <script> <!-- call that service and output that json into a javascript variable --> var resultantJSON = <%= Sample.getProjects() %> <!-- Now all that's left is to parse that json --> var projects = JSON.parse(resultantJSON); </script> </head> <body> ... ... </body> </html>现在，从数据库获取的所有结果都位于
Test.jsp的projects变量中。您可以像在 jsp 文件中使用传统javascript对象一样使用它们。
关于javascript - 如何将 hashmap 值从 java 文件传递到 Javascript，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39287195/