更改Tab和JTable之间的线条颜色

import javax.swing.*;
import javax.swing.plaf.basic.BasicTabbedPaneUI;
import java.awt.*;

public class CustomTabbedPaneUI extends BasicTabbedPaneUI {
    private Color lineColor;

    public CustomTabbedPaneUI(Color lineColor) {
        this.lineColor = lineColor;
    }

    @Override
    protected void paintContentBorder(Graphics g, int tabPlacement, int selectedIndex) {
        super.paintContentBorder(g, tabPlacement, selectedIndex);
        g.setColor(lineColor);
        Rectangle r = getTabBounds(tabPane, selectedIndex);
        g.fillRect(r.x, r.y + r.height - 2, r.width, 2);
    }
}

JTabbedPane tabbedPane = new JTabbedPane();
tabbedPane.setUI(new CustomTabbedPaneUI(Color.RED));

import javax.swing.*;
import javax.swing.table.DefaultTableCellRenderer;
import java.awt.*;

public class CustomTableCellRenderer extends DefaultTableCellRenderer {
    private Color lineColor;

    public CustomTableCellRenderer(Color lineColor) {
        this.lineColor = lineColor;
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        Component component = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        if (row < table.getRowCount() - 1) {
            component.setBackground(lineColor);
        }
        return component;
    }
}

JTable table = new JTable();
table.setDefaultRenderer(Object.class, new CustomTableCellRenderer(Color.RED));