Servlet仿CSDN动态验证码的生成-带数字和字母

package com.mucfc; import java.awt.Color; import java.awt.Graphics; import java.awt.Font; import java.awt.image.BufferedImage; import java.util.ArrayList; import java.util.List; import java.util.Random; /** * 生成验证码图片 * @author 林炳文Evankaka（博客：http://blog.csdn.net/evankaka） * @since 2015.6.22 */ public class AuthCode { public static final int AUTHCODE_LENGTH = 5; // 验证码长度 public static final int SINGLECODE_WIDTH = 20; // 单个验证码宽度 public static final int SINGLECODE_HEIGHT = 30; // 单个验证码高度 public static final int SINGLECODE_GAP = 4; // 单个验证码之间间隔 public static final int IMG_WIDTH = AUTHCODE_LENGTH * (SINGLECODE_WIDTH + SINGLECODE_GAP); public static final int IMG_HEIGHT = SINGLECODE_HEIGHT; public static final char[] CHARS = {'0','1', '2', '3', '4', '5', '6', '7', '8', '9' }; public static final char[] OPERATION={'+','-','*'}; static Random random = new Random(); /** * 返回图片中的数字 * @return String */ public static List<String> getAuthCode() { char char1 = CHARS[random.nextInt(CHARS.length)]; char char2 = CHARS[random.nextInt(CHARS.length)]; char opt = OPERATION[random.nextInt(OPERATION.length)]; StringBuffer buffer = new StringBuffer(); buffer.append(char1); buffer.append(getOperation(opt)); buffer.append(char2); String result=getResult(char1,char2,opt); List<String> list=new ArrayList<String>(); list.add(buffer.toString()); list.add(result); return list; } /** * 返回计算的结果 * @param operation * @return String */ public static String getResult(char char1,char char2,char operation){ int int1 = Integer.parseInt(String.valueOf(char1)); int int2 = Integer.parseInt(String.valueOf(char2)); if('+'==operation) return String.valueOf(int1+int2); else if ('-'==operation) return String.valueOf(int1-int2); else if ('*'==operation) return String.valueOf(int1*int2); else return null; } /** * 返回符号对应的中文 * @param operation * @return String */ public static String getOperation(char operation){ if('+'==operation) return "加上"; else if ('-'==operation) return "减去"; else if ('*'==operation) return "乘以"; else return null; } /** * 返回带数字的图片 * @return BufferedImage */ public static BufferedImage getAuthImg(String authCode) { // 设置图片的高、宽、类型 // RGB编码：red、green、blue BufferedImage img = new BufferedImage(IMG_WIDTH, IMG_HEIGHT, BufferedImage.TYPE_INT_BGR); // 得到图片上的一个画笔 Graphics g = img.getGraphics(); // 设置画笔的颜色，用来做背景色 g.setColor(Color.YELLOW); // 用画笔来填充一个矩形，矩形的左上角坐标，宽，高 g.fillRect(0, 0, IMG_WIDTH, IMG_HEIGHT); // 将画笔颜色设置为黑色，用来写字 g.setColor(Color.BLACK); // 设置字体：宋体、不带格式的、字号 g.setFont(new Font("宋体", Font.PLAIN, SINGLECODE_HEIGHT + 5)); // 输出数字 char c; for (int i = 0; i < authCode.toCharArray().length; i++) { // 取到对应位置的字符 c = authCode.charAt(i); // 画出一个字符串：要画的内容，开始的位置，高度 g.drawString(c + "", i * (SINGLECODE_WIDTH + SINGLECODE_GAP) + SINGLECODE_GAP / 2, IMG_HEIGHT); } Random random = new Random(); // 干扰素 for (int i = 0; i < 5; i++) { int x = random.nextInt(IMG_WIDTH); int y = random.nextInt(IMG_HEIGHT); int x2 = random.nextInt(IMG_WIDTH); int y2 = random.nextInt(IMG_HEIGHT); g.drawLine(x, y, x + x2, y + y2); } return img; } }