202012G02/SSODemo/SSOAuth/web/image.jsp

<%@ page  pageEncoding = "gb2312" contentType="image/jpeg" import = "javax.imageio.*,java.util.*,java.awt.image.*,java.awt.*" %>

<%!

    //在此处 获取并生成随机颜色

    Color getRandColor(Random random, int ff, int cc) {

        if (ff > 255)

            ff = 255;

        if (cc > 255)

            cc = 255;

        int r = ff + random.nextInt(cc - ff);

        int g = ff + random.nextInt(cc - ff);

        int b = ff + random.nextInt(cc - ff);

        return new Color(r, g, b);

    } %>

<%

    //在此处 设置JSP页面无缓存

    response.setHeader( "Pragma" , "No-cache" );

    response.setHeader( "Cache-Control" , "no-cache" );

    response.setDateHeader( "Expires" , 0);

    // 设置图片的长宽

    int width = 130;
    int height = 30;

    //设定被随机选取的中文字，此处中文字内容过多，不一一列出，只是举例说明下。
    String base = "\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u538b\u6162\u53d4\u80cc\u7ec6" ;

    //设置 备选随机汉字的个数

    int length = base.length();

    // 创建缓存图像

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

    // 获取图像
    Graphics g = image.getGraphics();

    // 创建随机函数的实例

    Random random = new Random();

    //此处 设定图像背景色

    g.setColor(getRandColor(random, 188, 235));

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

    //设置随机 备选的字体类型

    String[] fontTypes = { "\u5b8b\u4f53" , "\u65b0\u5b8b\u4f53" ,

            "\u9ed1\u4f53" , "\u6977\u4f53" , "\u96b6\u4e66" };

    int fontTypesLength = fontTypes.length;

    // 在图片背景上增加噪点，增加图片分析难度

    g.setColor(getRandColor(random, 180, 199));

    g.setFont( new Font( "Times New Roman" , Font.PLAIN, 14));

    for ( int i = 0; i < 4; i++) {

        g.drawString( "@*@*@*@*@*@*@*" ,

                0, 5 * (i + 2));

    }

    // 取随机产生的验证码 (4 个汉字 )

    // 保存生成的汉字字符串

    String sRand = "" ;

    for ( int i = 0; i < 4; i++) {

        int start = random.nextInt(length);

        String rand = base.substring(start, start + 1);

        sRand += rand;

        // 设置图片上字体的颜色

        g.setColor(getRandColor(random, 10, 150));

        // 设置字体格式

        g.setFont( new Font(fontTypes[random.nextInt(fontTypesLength)],

                Font.BOLD, 18 + random.nextInt(6)));

        // 将此汉字画到验证图片上面

        g.drawString(rand, 24 * i + 10 + random.nextInt(8), 24);

    }

    // 将验证码存入Session中

    session.setAttribute( "rand" , sRand);

    g.dispose();

    //将 图象输出到JSP页面中

    ImageIO.write(image, "JPEG" , response.getOutputStream());

    //关闭流

    out.clear();

    out=pageContext.pushBody();

%>