imagegenerator.java

JSP上传显示图片代码（转）-Sumongh Zone -JavaEye技术社区.rar

package test;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class ImageGenerator extends HttpServlet {
  /** *//**
   * 
   */
  private static final long serialVersionUID = -3938318741402322164L;//在序列化时指定的唯一标识

  private static 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);
  }

  private static String charsLong = "23456789abcdefghjklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";

  private static String charsShort = "0123456789";

  private static String chars = charsLong;

  @Override
  public void doGet(HttpServletRequest request, HttpServletResponse response) {
    try {
      int charsLength = chars.length();

      response.setHeader("Pragma", "No-cache");
      response.setHeader("Cache-Control", "no-cache");
      response.setDateHeader("Expires", 0);

      int width = 70, height = 20;//设置图片宽高
      BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);//构造一个类型为预定义图像类型之一的 BufferedImage。该图像的 ColorSpace 为默认的 sRGB 空间

      Graphics g = image.getGraphics(); //此方法返回 Graphics2D，但此处是出于向后兼容性的考虑

      Random random = new Random();//创建随机对象

      g.setColor(getRandColor(200, 250));//设置图片颜色
      g.fillRect(0, 0, width, height); //填充指定的矩形

      g.setFont(new Font("Times New Roman", Font.ITALIC, height)); //将此图形上下文的字体设置为指定字体

      g.setColor(getRandColor(160, 200));	//将此图形上下文的当前颜色设置为指定颜色
      for (int i = 0; i < 35; 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);	//在此图形上下文的坐标系中，使用当前颜色在点 (x1, y1) 和 (x, y) 之间画一条线
      }

      StringBuilder sRand = new StringBuilder();//一个可变的字符序列
      String[] fontNames = { "Times New Roman", "Arial", "Book antiqua", "" };

      for (int i = 0; i < 4; i++) {
        g.setFont(new Font(fontNames[random.nextInt(3)], Font.ITALIC, height));//将此图形上下文的字体设置为指定字体
        char rand = chars.charAt(random.nextInt(charsLength));
        sRand.append(rand);

        g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
        g.drawString(String.valueOf(rand), 16 * i + random.nextInt(6) + 3, height - random.nextInt(4));
      }

      g.setColor(getRandColor(160, 200));
      for (int i = 0; i < 30; i++) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(width);
        int yl = random.nextInt(width);
        g.drawLine(x, y, x + xl, y + yl);
      }

      request.getSession().setAttribute("Login_Image_Code", sRand.toString());	//设置session

      g.dispose();// 释放此图形的上下文以及它使用的所有系统资源

      try {
        Thread.sleep(100);
      } catch (Exception ex){
      }
      OutputStream os = response.getOutputStream();
      ImageIO.write(image, "JPEG", os);
      os.flush();
      os.close();
    } catch (Exception ex) {

    }
  }
}