java 怎么画圆

Question

java 怎么画圆啊
我现在想画一个类似雷达的图,要画一组同心圆,要怎么画啊,最好圆的边框能是虚线.

Answer 1

import javax.swing.JFrame;
public class TestFrame extends JFrame { /**
 * @param args
 */
public static void main(String[] args) {
// TODO Auto-generated method stub
TestFrame frame=new TestFrame();
frame.setBounds(0, 0, 200, 200);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getGraphics().setColor(java.awt.Color.BLUE);
frame.getGraphics().drawOval(10, 60, 100, 100);
}}

Answer 2

import   java.awt.Color;   
  import   java.awt.Dimension;   
  import   javax.swing.JPanel;   
  import   org.jfree.chart.ChartFactory;   
  import   org.jfree.chart.ChartPanel;   
  import   org.jfree.chart.JFreeChart;   
  import   org.jfree.chart.axis.NumberAxis;   
  import   org.jfree.chart.plot.PolarPlot;   
  import   org.jfree.data.xy.XYDataset;   
  import   org.jfree.data.xy.XYSeries;   
  import   org.jfree.data.xy.XYSeriesCollection;   
  import   org.jfree.ui.ApplicationFrame;   
  import   org.jfree.ui.RefineryUtilities;   
    
  public   class   PolarChartDemo1   extends   ApplicationFrame   
  {   
    
    public   PolarChartDemo1(String   s)   
    {   
            super(s);   
            JPanel   jpanel   =   createDemoPanel();   
            jpanel.setPreferredSize(new   Dimension(600,   500));   
            setContentPane(jpanel);   
    }   
    
    private   static   XYDataset   createDataset()   
    {   
            XYSeriesCollection   xyseriescollection   =   new   XYSeriesCollection();   
            XYSeries   xyseries   =   new   XYSeries("Series   1");   
            xyseries.add(0.0D,   2D);   
            xyseries.add(90D,   13D);   
            xyseries.add(180D,   9D);   
            xyseries.add(270D,   8D);   
            xyseriescollection.addSeries(xyseries);   
            XYSeries   xyseries1   =   new   XYSeries("Series   2");   
            xyseries1.add(90D,   -11.199999999999999D);   
            xyseries1.add(180D,   21.399999999999999D);   
            xyseries1.add(250D,   17.300000000000001D);   
            xyseries1.add(355D,   10.9D);   
            xyseriescollection.addSeries(xyseries1);   
            return   xyseriescollection;   
    }   
    
    private   static   JFreeChart   createChart(XYDataset   xydataset)   
    {   
            JFreeChart   jfreechart   =   ChartFactory.createPolarChart("Polar   Chart   Demo   1",   xydataset,   true,   false,   false);   
            jfreechart.setBackgroundPaint(Color.white);   
            PolarPlot   polarplot   =   (PolarPlot)jfreechart.getPlot();   
            polarplot.setBackgroundPaint(Color.lightGray);   
            polarplot.addCornerTextItem("Corner   Item   1");   
            polarplot.addCornerTextItem("Corner   Item   2");   
            NumberAxis   numberaxis   =   (NumberAxis)polarplot.getAxis();   
            numberaxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());   
            return   jfreechart;   
    }   
    
    public   static   JPanel   createDemoPanel()   
    {   
            JFreeChart   jfreechart   =   createChart(createDataset());   
            ChartPanel   chartpanel   =   new   ChartPanel(jfreechart);   
            chartpanel.setMouseZoomable(false);   
            return   chartpanel;   
    }   
    
    public   static   void   main(String   args[])   
    {   
            PolarChartDemo1   polarchartdemo1   =   new   PolarChartDemo1("Polar   Chart   Demo");   
            polarchartdemo1.pack();   
            RefineryUtilities.centerFrameOnScreen(polarchartdemo1);   
            polarchartdemo1.setVisible(true);   
    }   
  }   

Answer 3

public class HuaYuan{
public static void main(String[] args) {
               System.out.println('圆');
               System.out.println('○');
               System.out.println('●');
               System.out.println('◎');
               System.out.println('㊤');
               System.out.println('㊦');
               System.out.println('㊥');
               System.out.println('㊧');
               System.out.println('㊨');
}}

Answer 4

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.RenderingHints;
import java.awt.geom.Arc2D;
import javax.swing.JPanel;public class VA extends JPanel {
  private static final long serialVersionUID = 1L;  public static void main(String[] args) {
  }  public VA() {
    super();
    initialize();
  }  private void initialize() {
    this.setSize(300, 200);
    this.setLayout(new GridBagLayout());
  }  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    super.paint(g2);
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    double c[] = { 100, 100 };
    double r = 50;
    double alf = Math.PI / 3.;
    for (double r2 = r; r2 >= 0; r2 -= 10)
      g2
          .draw(new Arc2D.Double(c[0] - r2, c[1] - r2, 2 * r2, 2 * r2, -Math.toDegrees(Math.PI / 2. - alf / 2.), Math.toDegrees(2 * Math.PI - alf),
              Arc2D.OPEN));
  }
}

Answer 5

public class HuaYuan{
public static void main(String[] args) {
System.out.println('圆');
System.out.println('○');
System.out.println('●');
System.out.println('◎');
System.out.println('㊤');
System.out.println('㊦');
System.out.println('㊥');
System.out.println('㊧');
System.out.println('㊨');
}}
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太强了，红内裤外穿的超人啊。