JAVAを使用してJSPで円グラフを生成
サーバ側で画像を生成し、ページ内の画像をブラウザにまたがることができます.
package servlets;
import java.awt.*;
import java.awt.image.*;
import javax.imageio.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ImageServlet extends HttpServlet {
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("image/jpeg");
int width = 155; //
int height = 155;
int x = 5;
int y = 5;
int ellipseWidth = 145;
int ellipseHeight = 145;
BufferedImage bi = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = (Graphics2D) bi.getGraphics();
RenderingHints renderHints = new RenderingHints(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setRenderingHints(renderHints);
g2.setBackground(Color.WHITE);
g2.clearRect(0, 0, width, height);
g2.setPaint(Color.BLACK);
//
Ellipse2D.Double ellipse = new Ellipse2D.Double(x, y, ellipseWidth, ellipseHeight);
g2.draw(ellipse);
g2.setPaint(Color.RED);
g2.fillArc(x, y, ellipseWidth, ellipseHeight, 0, 120);
g2.setPaint(Color.GREEN);
g2.fillArc(x, y, ellipseWidth, ellipseHeight, 120 , 120);
g2.setPaint(Color.blue);
g2.fillArc(x, y, ellipseWidth, ellipseHeight, 240, 120);
ImageIO.write(bi, "jpg", response.getOutputStream());
}
}
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB18030">
<title>Insert title here</title>
</head>
<body>
<img src="http://localhost:8080/myproject/ImageServlet" id="myImg">
</body>
</html>