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.util.Random; import javax.imageio.ImageIO; import javax.imageio.stream.ImageOutputStream; public class RandomNumUtil { private ByteArrayInputStream image;//图像 private String str;//验证码 private RandomNumUtil(){ init();//初始化属性 } public static RandomNumUtil Instance(){ return new RandomNumUtil(); } public ByteArrayInputStream getImage(){ return this.image; } public String getString(){ return this.str; } private void init() { // 在内存中创建图象 int width=85, height=20; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics g = image.getGraphics(); // 生成随机类 Random random = new Random(); // 设定背景色 g.setColor(getRandColor(200,250)); g.fillRect(0, 0, width, height); // 设定字体 g.setFont(new Font("Times New Roman",Font.PLAIN,18)); // 随机产生155条干扰线,使图象中的认证码不易被其它程序探测到 g.setColor(getRandColor(160,200)); for (int i=0;i<155;i++) { int x = random.nextInt(width); int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12); g.drawLine(x,y,x+xl,y+yl); } // 取随机产生的认证码(6位数字) String sRand=""; for (int i=0;i<6;i++){ String rand=String.valueOf(random.nextInt(10)); sRand+=rand; // 将认证码显示到图象中 g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110))); // 调用函数出来的颜色相同,可能是因为种子太接近,所以只能直接生成 g.drawString(rand,13*i+6,16); } //赋值验证码 this.str=sRand; //图象生效 g.dispose(); ByteArrayInputStream input=null; ByteArrayOutputStream output = new ByteArrayOutputStream(); try{ ImageOutputStream imageOut = ImageIO.createImageOutputStream(output); ImageIO.write(image, "JPEG", imageOut); imageOut.close(); input = new ByteArrayInputStream(output.toByteArray()); }catch(Exception e){ System.out.println("验证码图片产生出现错误:"+e.toString()); } this.image=input; } private Color getRandColor(int fc,int bc){ Random random = new Random(); if(fc>255) fc=255; if(bc>255) bc=255; int r=fc+random.nextInt(bc-fc); int g=fc+random.nextInt(bc-fc); int b=fc+random.nextInt(bc-fc); return new Color(r,g,b); } }