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 = "青半火法题建赶位唱海七女任件感准音答哥际旧神座章压慢叔背细" ; 
    //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 = { "宋体" , "新宋体" , 
           "黑体" , "楷体" , "隶书" }; 
    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
    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 = "青半火法题建赶位唱海七女任件感准音答哥际旧神座章压慢叔背细" ;
    //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 = { "宋体" , "新宋体" ,
           "黑体" , "楷体" , "隶书" };
    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