jpegservlet.java

JAVA案例开发集锦源代码 袁然 郑自国编

package wmj.servlet;

/**
 * @author wangmj
 * @mail  <a mailto="[e-mail]">
 * 2005-2-18 2005
 * 利用Servlet生成动态的图像
 * JPEGServlet.java
 */
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class JPEGServlet extends HttpServlet{
	/**
	 * 处理 Http Get request
	 */
	public void doGet(HttpServletRequest request,HttpServletResponse response)
		throws ServletException,IOException{
		response.setContentType("image/jpeg");
		//注意这里的MIME 类型
		ServletOutputStream out = response.getOutputStream();
		//构造一个缓冲图像
		BufferedImage image = new BufferedImage(750,30,BufferedImage.TYPE_INT_RGB);
		int per = 0;
		per = Integer.parseInt((String)getInitParameter("size"));
		
		Graphics graphics = image.getGraphics();
		graphics.setColor(Color.green);
		graphics.fillRect(0,0,750,30);//first draw a rectangle
		graphics.setColor(Color.YELLOW);//change color
		graphics.fillRect(0,0,750*per/100,30);
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
		encoder.encode(image);
		out.close();
	}
	/**
	 * 处理 Http Post request,和doGet一样
	 */
	public void doPost(HttpServletRequest request,HttpServletResponse response)
		throws IOException,ServletException{
		doGet(request,response);
	}
}