JFreeChart生成图片返回BYTE设置编码格式
时间: 2023-09-21 20:07:42 浏览: 49
你可以使用以下代码来生成图片并将其转换为字节数组,同时设置编码格式为UTF-8:
```java
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GradientPaint;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.renderer.category.BarRenderer;
import org.jfree.data.category.DefaultCategoryDataset;
public class ChartGenerator {
public static byte[] generateChartImage() throws IOException {
// Create a dataset
DefaultCategoryDataset dataset = new DefaultCategoryDataset();
dataset.addValue(1.0, "Series 1", "Category 1");
dataset.addValue(2.0, "Series 1", "Category 2");
dataset.addValue(3.0, "Series 1", "Category 3");
dataset.addValue(4.0, "Series 1", "Category 4");
// Create a chart
JFreeChart chart = ChartFactory.createBarChart(
"Chart Title",
"Category",
"Value",
dataset,
PlotOrientation.VERTICAL,
false,
true,
false
);
// Customize the chart
chart.setBackgroundPaint(new GradientPaint(0, 0, Color.white, 0, 1000, Color.blue));
CategoryPlot plot = (CategoryPlot) chart.getPlot();
plot.setBackgroundPaint(Color.white);
plot.setDomainGridlinePaint(Color.black);
plot.setRangeGridlinePaint(Color.black);
CategoryAxis domainAxis = plot.getDomainAxis();
domainAxis.setLabelFont(new Font("SansSerif", Font.BOLD, 16));
domainAxis.setTickLabelFont(new Font("SansSerif", Font.BOLD, 16));
NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
rangeAxis.setLabelFont(new Font("SansSerif", Font.BOLD, 16));
rangeAxis.setTickLabelFont(new Font("SansSerif", Font.BOLD, 16));
BarRenderer renderer = (BarRenderer) plot.getRenderer();
renderer.setDrawBarOutline(false);
renderer.setBaseItemLabelGenerator(new LabelGenerator());
renderer.setBaseItemLabelsVisible(true);
renderer.setBaseItemLabelFont(new Font("SansSerif", Font.BOLD, 16));
// Generate the chart image
BufferedImage chartImage = chart.createBufferedImage(640, 480);
// Convert the chart image to a byte array
ByteArrayOutputStream chartOut = new ByteArrayOutputStream();
ChartUtilities.writeBufferedImage(chartOut, "png", chartImage);
byte[] chartBytes = chartOut.toByteArray();
return chartBytes;
}
}
```
上面的代码使用了JFreeChart库来生成一个带有标签的条形图,并将其转换为PNG格式的字节数组。使用`ByteArrayOutputStream`类将图像写入字节数组时,可以指定要使用的编码格式(例如UTF-8)。