Create VerifyCode by jsp of java

使用java生成VerifyCode

VerifyCode.jsp

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="UTF-8" %>
<%!
Color getRandColor(int fc,int bc){
		//给定范围获得随机颜色
        Random random = new Random();
        if(fc>255) fc=255;
        if(bc>255) bc=255;
        int r=fc+random.nextInt(bc-fc);
        int g=fc+random.nextInt(bc-fc);
        int b=fc+random.nextInt(bc-fc);
        return new Color(r,g,b);
        }
%>
<%
try
{
//设置页面不缓存
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);

out.println("01 _  verifyCode has created!!!");

String verifyCode = "9657";//(String)request.getSession().getAttribute(SessionConstant.LOGIN_USER_VERIFYCODE);
//End Modify 

// 在内存中创建图象
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

// 获取图形上下文
Graphics g = image.getGraphics();

//生成随机类
Random random = new Random();

// 设定背景色
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);

//设定字体
g.setFont(new Font("Times New Roman",Font.PLAIN,18));

//画边框
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);


// 随机产生155条干扰线,使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160,200));
for (int i=0;i<155;i++)
{
	int x = random.nextInt(width);
	int y = random.nextInt(height);
	int xl = random.nextInt(12);
	int yl = random.nextInt(12);
	g.drawLine(x,y,x+xl,y+yl);
}


String num = "";
for (int i=0;i<4;i++){
    num = verifyCode.substring(i, i+1);
    // 将认证码显示到图象中
    g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//调用函数出来的颜色相同,可能是因为种子太接近,所以只能直接生成
    g.drawString(num,13*i+6,16);
}

// 图象生效
g.dispose();
// 输出图象到页面
ServletOutputStream os = response.getOutputStream();
ImageIO.write(image, "JPEG", os);
out.println("verifyCode has created!!!");
//加上后面的几句就是为了解决抛出的异常IllegalStateException
os.flush(); 
os.close(); 
os=null; 
response.flushBuffer(); 
out.clear(); 
out = pageContext.pushBody();
}
catch(Exception ex)
{
	out.println("Exception:" + ex.toString());
}

%> 

调用方法:在需要调用VerifyCode的页面使用<image src="VerifyCode.jsp"/>即可 

你可能感兴趣的:(create)