关于在eclipse中使用JFreechart和mysql数据库显示条形图/饼图
我正在 Java EE 平台上开发一个简单的应用程序，使用 MYSQL 和 JFreeChart 数据库生成 3D 条形图，但 3D 效果可见，但在背景上看不到条形，因此我无法在条形图中显示条形图，同样是当我尝试用饼图来做到这一点时。
这是我的代码：
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="java.io.*" %>
<%@ page import="java.sql.*" %>
<%@ page import="org.jfree.data.jdbc.JDBCCategoryDataset" %>
<%@ page import="org.jfree.chart.plot.PlotOrientation" %>
<%@ page import="org.jfree.chart.JFreeChart" %>
<%@ page import="org.jfree.chart.ChartUtilities" %>
<%@ page import="org.jfree.chart.ChartFactory" %>
<%
String connectionURL = "jdbc:mysql://localhost/tester?user=root&password=root&useUnicode=true&characterEncoding=utf-8";
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection (connectionURL);
String query = "SELECT * from charter";
JDBCCategoryDataset dataset = new JDBCCategoryDataset(con);
dataset.executeQuery(query);
JFreeChart chart = ChartFactory.createBarChart3D("Test", "Name", "ID",dataset, PlotOrientation.VERTICAL, true, true, false);
try {
ChartUtilities.saveChartAsJPEG(new File("E:/project/jfreechart3D/img/barchart_3D.jpeg"),chart,400, 300);
}
catch (IOException e) {
System.out.println("No chart creation.");
}
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<IMG SRC="E:/project/jfreechart3D/img/barchart_3D.jpeg" WIDTH="600" HEIGHT="400" BORDER="0" USEMAP="#chart" />
</body>
</html>
I am developing a simple application on Java EE platform using database as MYSQL and JFreeChart to generate 3D Bar Charts but 3D effect is visible but the bars are not seen on that background,thus I am unable to display the bars in bar chart and same is with when I try to do this with Pie Charts.
Here is mine code:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="java.io.*" %>
<%@ page import="java.sql.*" %>
<%@ page import="org.jfree.data.jdbc.JDBCCategoryDataset" %>
<%@ page import="org.jfree.chart.plot.PlotOrientation" %>
<%@ page import="org.jfree.chart.JFreeChart" %>
<%@ page import="org.jfree.chart.ChartUtilities" %>
<%@ page import="org.jfree.chart.ChartFactory" %>
<%
String connectionURL = "jdbc:mysql://localhost/tester?user=root&password=root&useUnicode=true&characterEncoding=utf-8";
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection (connectionURL);
String query = "SELECT * from charter";
JDBCCategoryDataset dataset = new JDBCCategoryDataset(con);
dataset.executeQuery(query);
JFreeChart chart = ChartFactory.createBarChart3D("Test", "Name", "ID",dataset, PlotOrientation.VERTICAL, true, true, false);
try {
ChartUtilities.saveChartAsJPEG(new File("E:/project/jfreechart3D/img/barchart_3D.jpeg"),chart,400, 300);
}
catch (IOException e) {
System.out.println("No chart creation.");
}
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<IMG SRC="E:/project/jfreechart3D/img/barchart_3D.jpeg" WIDTH="600" HEIGHT="400" BORDER="0" USEMAP="#chart" />
</body>
</html>
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相反，编写一个调用
ChartUtilities方法，例如writeChartAsJPEG()或writeChartAsPNG()。前者会更压缩，但后者会更锐利。 此处有一个示例。让您的 JSP 包含一个标记，其中src引用您的 servlet。Instead, write a servlet that invokes one of the
ChartUtilitiesmethods such aswriteChartAsJPEG()orwriteChartAsPNG(). The former will be more compressed, but the latter will be sharper. There's an example here. Have your JSP include a tag where thesrcrefers to your servlet.