JSP中文验证码

<%@ 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); 
    //获取图像对象  
    Graphics g = image.getGraphics(); 
    //创建随机函数  
    Random random = new Random(); 
    //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S ession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();   
%> 
<%@ 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 www.2cto.com
    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);
    //获取图像对象
    Graphics g = image.getGraphics();
    //创建随机函数
    Random random = new Random();
    //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S ession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(); 
%>

摘自 落日小屋