chart.getXYPlot().setDomainGridlinePaint报错org.jfree.chart.plot.SpiderWebPlot cannot be cast to org.jfree.chart.plot.XYPlot如何解决
时间: 2023-12-18 20:05:04 浏览: 88
这个错误的原因是`chart.getXYPlot()`方法返回类型是`XYPlot`,但是你的实际图表类型是`SpiderWebPlot`,所以不能强制转换。解决这个问题的方法是判断图表类型是否为`XYPlot`,可以使用`instanceof`运算符来实现。示例代码如下:
```
if (chart.getPlot() instanceof XYPlot) {
XYPlot plot = (XYPlot) chart.getPlot();
plot.setDomainGridlinePaint(Color.BLACK);
}
```
这段代码先判断`chart.getPlot()`返回的类型是否为`XYPlot`,如果是则将其强制转换为`XYPlot`对象,并设置X轴网格线的颜色为黑色。如果不是`XYPlot`类型,则不执行任何操作。
相关问题
创建一个动态曲线图JFreechar对象
好的,以下是在Java中创建动态曲线图JFreeChart对象的示例代码:
```java
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.time.Second;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.xy.XYDataset;
import javax.swing.*;
import java.awt.*;
public class DynamicLineChart extends JFrame {
private TimeSeries series;
public DynamicLineChart(String title) {
super(title);
series = new TimeSeries("Random Data");
TimeSeriesCollection dataset = new TimeSeriesCollection(series);
JFreeChart chart = createChart(dataset);
ChartPanel chartPanel = new ChartPanel(chart);
chartPanel.setPreferredSize(new Dimension(500, 270));
setContentPane(chartPanel);
}
private JFreeChart createChart(XYDataset dataset) {
JFreeChart chart = ChartFactory.createTimeSeriesChart(
"Dynamic Line Chart",
"Time",
"Value",
dataset,
true,
true,
false
);
XYPlot plot = chart.getXYPlot();
plot.setBackgroundPaint(Color.lightGray);
plot.setDomainGridlinePaint(Color.white);
plot.setRangeGridlinePaint(Color.white);
return chart;
}
public void addData(double data) {
series.add(new Second(), data);
}
public static void main(String[] args) {
DynamicLineChart chart = new DynamicLineChart("Dynamic Line Chart");
chart.pack();
RefineryUtilities.centerFrameOnScreen(chart);
chart.setVisible(true);
while (true) {
double data = Math.random() * 100;
chart.addData(data);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
```
这个示例代码创建了一个动态曲线图,并在窗口中显示出来。通过addData方法可以向图表中添加数据,示例代码中每隔一秒钟随机生成一个数据点并添加到图表中。你可以根据你的需要对代码进行修改和扩展。
基于网络爬虫技术的新闻分析系统的设计与实现的数据展示模块使用jfreechart的代码怎么写
下面是一个简单的使用 JFreeChart 进行数据展示的示例代码:
```java
import java.awt.Color;
import java.awt.Font;
import java.util.ArrayList;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;
public class MyChart extends ApplicationFrame {
public MyChart(String title) {
super(title);
}
public void createChart(ArrayList<Double> data, String xLabel, String yLabel) {
XYSeriesCollection dataset = new XYSeriesCollection();
XYSeries series = new XYSeries("Data");
for (int i = 0; i < data.size(); i++) {
series.add(i + 1, data.get(i));
}
dataset.addSeries(series);
JFreeChart chart = ChartFactory.createXYLineChart(
"Data Chart",
xLabel,
yLabel,
dataset,
PlotOrientation.VERTICAL,
true,
true,
false
);
chart.getTitle().setFont(new Font("Arial", Font.BOLD, 18));
chart.setBackgroundPaint(Color.WHITE);
XYPlot plot = chart.getXYPlot();
plot.setBackgroundPaint(Color.WHITE);
plot.setDomainGridlinePaint(Color.BLACK);
plot.setRangeGridlinePaint(Color.BLACK);
XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer();
renderer.setSeriesPaint(0, Color.BLUE);
renderer.setSeriesStroke(0, new BasicStroke(2.0f));
plot.setRenderer(renderer);
setContentPane(new ChartPanel(chart));
pack();
RefineryUtilities.centerFrameOnScreen(this);
setVisible(true);
}
}
```
使用示例:
```java
import java.util.ArrayList;
import java.util.Random;
public class Main {
public static void main(String[] args) {
ArrayList<Double> data = new ArrayList<>();
Random rand = new Random();
for (int i = 0; i < 10; i++) {
data.add(rand.nextDouble() * 100);
}
MyChart chart = new MyChart("Data Chart");
chart.createChart(data, "X-Axis Label", "Y-Axis Label");
}
}
```
这个例子展示了如何通过 JFreeChart 创建一个简单的数据曲线图。你可以将 `data` 替换为你自己的数据,`xLabel` 和 `yLabel` 分别表示 X 轴和 Y 轴的标签。请注意,这只是一个基本的示例。你可以根据自己的需求进行修改和扩展。
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