JSP生成验证码

记录

<%@ page contentType="image/jpeg"
    import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"
%>
<%!
	Color getRandColor(int fc, int bc)
	{
		Random rd =  new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = rd.nextInt(bc - fc);
		int g = rd.nextInt(bc - fc);
		int b = rd.nextInt(bc - fc);
		return new Color(r,g,b);
	}
%>
<%
	response.setHeader("Pragma", "No-cache");
	response.setHeader("Cache-Control","no-cache");
	response.setDateHeader("Expires", 0);
	
	int width = 60, height = 20;
	BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
	Graphics g = image.getGraphics();
	Random rd = new Random();
	g.setColor(getRandColor(200,250));
	g.fillRect(0, 0, width, height);
	g.setFont(new Font("Times New Roman",Font.PLAIN,18));
	
	g.setColor(new Color(255,255,255));
	g.drawRect(0, 0, width - 1, height - 1);
	
	g.setColor(getRandColor(160,200));

	for (int i=0;i<155;i++)
	{
	     int x = rd.nextInt(width);
	     int y = rd.nextInt(height);
	     int xl = rd.nextInt(12);
	     int yl = rd.nextInt(12);
	     g.drawLine(x,y,x+xl,y+yl);
	}
	
	String sRand="";
    for (int i=0;i<4;i++){
        String rand=String.valueOf(rd.nextInt(10));
        sRand+=rand;
        g.setColor(new Color(20+rd.nextInt(110),20+rd.nextInt(110),20+rd.nextInt(110)));
        g.drawString(rand,13*i+6,16);
    }
    session.setAttribute("rand",sRand);
    
    g.dispose();
	
	ImageIO.write(image, "JPEG", response.getOutputStream());
	out.clear();
	out = pageContext.pushBody();
%>

<img src = "code.jsp"/>