createimageservlet.java

五种不同功能的jsp验证码提供下载

package web;

import java.io.*;
import java.awt.*;
import java.awt.image.*;

import javax.servlet.*;
import javax.servlet.http.*;

import com.sun.image.codec.jpeg.*;


public class CreateImageServlet extends HttpServlet {

	protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {

		response.setContentType("image/jpeg");	//设置响应的MIME类型

		createImage(response.getOutputStream());

	}

	private void createImage(OutputStream out) {

		int width = 100;
		int height = 100;

		BufferedImage bi = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);

		Graphics2D g = bi.createGraphics();

		// 设置背景色
		g.setBackground(Color.BLUE);

		g.clearRect(0, 0, width, height);

		// 设置前景色
		g.setColor(Color.RED);

		// 开始画图
		g.drawLine(0, 0, 99, 199);

		// 结束画图
		g.dispose();

		bi.flush();

		// 当绘制完成后，调用com.sun.image.codec.jpeg包的JPEG编码器对其编码。
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
		JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(bi);
		param.setQuality(1.0f, false);
		encoder.setJPEGEncodeParam(param);

		try {
			encoder.encode(bi);
		} catch (IOException ioe) {
			ioe.printStackTrace();
		}
	}
}