在java中从jfreechart中的range轴获取后，如何在域轴上设置刻度单位？

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartFrame;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.NumberTickUnit;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.data.category.DefaultCategoryDataset;

public class ChartExample {
    public static void main(String[] args) {
        // 创建数据集
        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(1, "Series 1", "Category 1");
        dataset.addValue(2, "Series 1", "Category 2");
        dataset.addValue(3, "Series 1", "Category 3");

        // 创建图表
        JFreeChart chart = ChartFactory.createBarChart(
                "Chart Title",
                "Category",
                "Value",
                dataset
        );

        // 获取绘制区域
        CategoryPlot plot = chart.getCategoryPlot();

        // 获取域轴
        CategoryAxis domainAxis = plot.getDomainAxis();

        // 设置刻度单位为1
        TickUnit tickUnit = new NumberTickUnit(1);
        domainAxis.setTickUnit(tickUnit);

        // 显示图表
        ChartFrame frame = new ChartFrame("Chart", chart);
        frame.pack();
        frame.setVisible(true);
    }
}