image.java

Java开发的权限管理的例子

package org.artemis.manager.common.image;
import java.awt.*;
import java.awt.image.*;
import java.util.*;

/**
 * @author 
 *
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
public class Image {
    //字符的位数
  public final int STRING_LENGTH = 4;
  public String sRand="";
 
  public Color getRandColor(int fc,int bc){//给定范围获得随机颜色
   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);
   }
  
  public BufferedImage creatImage() {

      // 在内存中创建图象
      int width = 60, 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(new Color(255,244,175));//(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100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 < 100; 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);
      }
      //产生随机数，包含大小写字母和数字
      //修改此处可以支持数字，字母，或者字母数字组合
      sRand = RandomStringUtils.randomNumeric(this.STRING_LENGTH);
      for (int i = 0; i < this.STRING_LENGTH; i++) {
          String rand = String.valueOf(sRand.charAt(i));
      // 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)));
          g.drawString(rand, 13 * i + 6, 16);
      }
     // 图象生效
      g.dispose();
      return image;
  }
}