JAVA绘图（Graphics2D ）（简单代码例子实现）

import java.awt.BasicStroke;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Container;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.geom.Rectangle2D;

import javax.swing.ImageIcon;
import javax.swing.JFrame;

public class Main extends JFrame {
     
	public Main() {
     
		setTitle("绘制几何图形");
		setBounds(100, 200, 500, 500);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		setVisible(true);

		Container c = getContentPane();
		MyCanvas canvas = new MyCanvas();
		c.add(canvas);
	}

	private class MyCanvas extends Canvas {
     
		@Override
		public void paint(Graphics g) {
     
			Graphics2D g2 = (Graphics2D) g;//新绘图类
			
			Image img = new ImageIcon("src/a.png").getImage();//获取图片来源
			g2.drawImage(img, 50, 0, this);
			
			Color c = Color.RED;//设置颜色属性
			Stroke stroke = new BasicStroke(8);//设置画笔属性
			Font font = new Font("隶书", Font.BOLD, 16);
			g2.setFont(font);//加载字体
			g2.drawString("你好", 20, 30);//
			
//			g2.setStroke(stroke);//加载画笔
			
			/*BasicStroke.CAP_ROUND : 圆角末端
			 *BasicStroke.CAP_BUTT :无修饰末端
			 *BasicStroke.CAP_SQUARE :正方形末端
			 *
			 *BasicStroke.JOIN_BEVEL :平角
			 *BasicStroke.JOIN_MITER :尖角（默认）
			 *BasicStroke.JOIN_ROUND :圆角
			 * */
			stroke = new BasicStroke(12, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND);
			g2.setStroke(stroke);//加载画笔
			
			
//			g2.setColor(c);
			g2.setColor(Color.BLUE);
			g2.drawOval(60, 20, 30, 30);// 画了一个圆
			g2.setColor(c);
			g2.fillRect(60, 20, 20, 20);// 画矩形
			g2.setColor(Color.BLUE);

			Shape shape1 = new Rectangle2D.Double(110, 5, 100, 100);// 矩形圆形对象
			g2.fill(shape1);// 画这个图形

			Shape shape2 = new Rectangle2D.Double(220, 15, 80, 80);// 矩形圆形对象
			g2.fill(shape2);// 画这个图形

			g2.drawArc(320, 25, 100, 50, 270, 200);// 弧形

			g2.drawLine(5, 120, 100, 120);//横线
			g2.drawLine(50, 120, 50, 200);//垂直线

			g2.drawRoundRect(120, 120, 100, 50, 10, 10);// 圆角矩形

			int x[] = {
      250, 300, 250, 300 };
			int y[] = {
      130, 130, 200, 200 };
//			g2.drawPolygon(x, y, 4);// 多边形

			g2.drawPolyline(x, y, 4);// 多边线
			
			
		}
	}

	public static void main(String args[]) {
     
		Main m = new Main();

	}
}

运行结果为：