JSP随机验证图片如何制作

package icewee.image; import java.awt.basicstroke; import java.awt.color; import java.awt.font; import java.awt.graphics2d; import java.awt.renderinghints; import java.awt.geom.line2d; import java.awt.image.bufferedimage; import java.util.random; public class tokenutil { private static final string base = "23456789abcdefghjklmnpqrstuvwxyzabcdefhijklmnpqrstuvwxyz"; private static final int length = base.length(); public static bufferedimage createtokenimage(int width, int height, string randomcode) { bufferedimage image = new bufferedimage(width, height, bufferedimage.type_int_rgb); graphics2d g = image.creategraphics(); random random = new random(); g.setcolor(new color(230, 230, 250)); // 设置背景色 g.fillrect(0, 0, width, height); // 填充背景 g.setcolor(color.black); // 绘制边缘 g.drawrect(-1, -1, width + 1, height + 1); g.setcolor(color.gray); // 设置字体,随机选择字体,暂设置8种字体 font font = new font((new string[] { "arial", "arial black", "arial italic", "courier new", "courier new bold italic", "courier new italic", "franklin gothic medium", "franklin gothic medium italic" })[random.nextint(8)], font.plain, 30); // g.setstroke(new basicstroke((float)(math.random()), // basicstroke.cap_butt, basicstroke.join_bevel)); g.setfont(font); // 定义字体颜色范围 int red = random.nextint(160), green = random.nextint(50), blue = random .nextint(50); // 定义一个无干扰线区间和一个起始位置 int nor = random.nextint(50), rsta = random.nextint(131); // 绘制干扰正弦曲线 m:曲线平折度, d:y轴常量 v:x轴焦距 int m = random.nextint(15) + 5, d = random.nextint(23) + 15, v = random .nextint(5) + 1; double x = 0.0; double y = m * math.sin(math.toradians(v * x)) + d; double px, py; for (int i = 0; i < 131; i++) { px = x + 1; py = m * math.sin(math.toradians(v * px)) + d; if (rsta < i && i < (rsta + nor)) g.setcolor(new color(230, 230, 250)); else g.setcolor(new color(red, green, blue)); // 随机设置像素点宽带(线宽) g.setstroke(new basicstroke((float) (math.random() + 1.5f))); g.draw(new line2d.double(x, y, px, py)); x = px; y = py; } char[] codes = randomcode.tochararray(); for (int i = 0; i < codes.length; i++) { // 旋转图形 int degree = (random.nextint(20) - 10) % 360; double ang = degree * 0.0174532925; // 将角度转为弧度 g.rotate(ang, width / 2, height / 2); g.setcolor(new color(red, green, blue)); g.setrenderinghint(renderinghints.key_antialiasing, renderinghints.value_antialias_on); int gr = random.nextint(8); g.drawstring(string.valueof(codes[i]), 24 * i + 10 + gr, 38); } g.dispose(); return image; } public static string createrandomcode(int size, int width, int height) { stringbuffer randomcode = new stringbuffer(); for (int i = 0; i < size; i++) { random random = new random(); int start = random.nextint(length); string strrand = base.substring(start, start + 1); randomcode.append(strrand); } return randomcode.tostring(); } }

<%@ page contenttype="image/jpeg" pageencoding="gbk"%> <%@ page import="java.awt.image.bufferedimage" %> <%@page import="javax.imageio.imageio" %> <%@ page import="com.icesoft.image.tokenutil" %> <% //设置页面不缓存 response.setheader("pragma", "no-cache"); response.setheader("cache-control", "no-cache"); response.setdateheader("expires", 0); int width = 120, height = 50; string randomcode = tokenutil.createrandomcode(4, width, height); system.out.println("生成的随机码：" + randomcode); bufferedimage image = tokenutil.createtokenimage(width, height, randomcode); imageio.write(image, "jpeg", response.getoutputstream()); response.flushbuffer(); out.clear(); out = pagecontext.pushbody(); %>