简单验证码 工具

package tarena.action; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.Map; import java.util.Random; import com.sun.image.codec.jpeg.ImageFormatException; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; public final class ImageUtil { private static final String[] chars = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "东", "南", "西", "北", "中", "发", "白" }; private static final int SIZE = 5; private static final int LINES = 20; private static final int WIDTH = 200; private static final int HEIGHT = 100; private static final int FONT_SIZE = 30; public static Map<String,BufferedImage> createImage() { StringBuffer sb = new StringBuffer(); BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB); Graphics graphic = image.getGraphics(); graphic.setColor(Color.LIGHT_GRAY); graphic.fillRect(0, 0, WIDTH, HEIGHT); Random ran = new Random(); //画随机字符 for(int i=1;i<=SIZE;i++){ int r = ran.nextInt(chars.length); graphic.setColor(getRandomColor()); graphic.setFont(new Font(null,Font.BOLD+Font.ITALIC,FONT_SIZE)); graphic.drawString(chars[r],(i-1)*WIDTH/SIZE , HEIGHT/2); sb.append(chars[r]);//将字符保存，存入Session } //画干扰线 for(int i=1;i<=LINES;i++){ graphic.setColor(getRandomColor()); graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT), ran.nextInt(WIDTH),ran.nextInt(HEIGHT)); } Map<String,BufferedImage> map = new HashMap<String,BufferedImage>(); map.put(sb.toString(), image); return map; } public static InputStream getInputStream( BufferedImage image) throws Exception{ //将图片给imageStream赋值 ByteArrayOutputStream bos = new ByteArrayOutputStream(); JPEGImageEncoder jpegCoder = JPEGCodec.createJPEGEncoder(bos); jpegCoder.encode(image); //获取压缩处理后的图片信息 byte[] bys = bos.toByteArray(); return new ByteArrayInputStream(bys); } public static Color getRandomColor(){ Random ran = new Random(); Color color = new Color(ran.nextInt(256),ran.nextInt(256),ran.nextInt(256)); return color; } }