使用AWT组件实现验证码功能

 1 import java.awt.Color; 2 import java.awt.Font; 3 import java.awt.FontMetrics; 4 import java.awt.Graphics2D; 5 import java.awt.image.BufferedImage; 6 import java.io.File; 7 import java.io.IOException; 8 import java.util.Random; 9 10 import javax.imageio.ImageIO;11 12 public class Test {13 14     /**15      * @param args16      * @throws IOException 17      */18     public static void main(String[] args) throws IOException {19         //用于随机生成验证码的字符串集20         String[] strs = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R"21                         ,"S","T","U","V","W","X","Y","Z","a","b","c","d","e","f","g","h","i","j"22                         ,"k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","0","1"23                         ,"2","3","4","5","6","7","8","9"};24         //随机生成干扰线的纵坐标y1和y225         Random y1Random = new Random();26         Random y2Random = new Random();27         int y1 = y1Random.nextInt(31);28         int y2 = y2Random.nextInt(31);29         30         //随机生成用于组成验证码的字符串所在集的下标值31         Random code1Random = new Random();32         Random code2Random = new Random();33         Random code3Random = new Random();34         Random code4Random = new Random();35         int code1Index = code1Random.nextInt(62);36         int code2Index = code2Random.nextInt(62);37         int code3Index = code3Random.nextInt(62);38         int code4Index = code4Random.nextInt(62);39         40         //随机生成rgb颜色41         Random rRandom = new Random();42         Random gRandom = new Random();43         Random bRandom = new Random();44         int r = rRandom.nextInt(256);45         int g = gRandom.nextInt(256);46         int b = bRandom.nextInt(256);47         Color color = new Color(r, g, b);48         49         //拼接成完整字符串50         String codeString = strs[code1Index] + strs[code2Index] + strs[code3Index] + strs[code4Index];51         52         //定义一个宽70像素,高30像素的jpg图片53         BufferedImage bi = new BufferedImage(70, 30, BufferedImage.TYPE_INT_RGB);54         //定义graphis绘画对象55         Graphics2D graphics2d = bi.createGraphics();        56         graphics2d.setBackground(Color.WHITE);57         graphics2d.setColor(color);58         graphics2d.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 20));59         graphics2d.clearRect(0, 0, 70, 30);
　　　　　　 //绘制干扰线60         graphics2d.drawLine(0, y1, 70, y2);61         62         //居中绘制字符串63         FontMetrics fontMetrics = graphics2d.getFontMetrics();64         int stringWidth = fontMetrics.stringWidth(codeString);65         int stringAscent = fontMetrics.getAscent();66         int xCode = 70 / 2 - stringWidth / 2;67         int yCode = 30 / 2 + stringAscent / 2;68         graphics2d.drawString(codeString, xCode, yCode);69         70         //输出图片71         File file = new File("C:\\Users\\zhengbing\\Desktop\\image.jpg");72         ImageIO.write(bi, "jpeg", file);73     }74 75 }

最后可以返回校验字符串codeString,来达到验证的功能