import java.awt.*;

import java.awt.image.BufferedImage;

import java.awt.font.TextLayout;

import java.awt.Graphics2D;

import java.awt.geom.Rectangle2D;

public class CombineRndImg {

    public void run(String FilePath,String FileName) throws Exception

    {

      String text = getRnd(8);

      BufferedImage im = ImageIO.read(new java.io.File(FilePath+FileName));

          Graphics2D g = im.createGraphics();

          //去除鋸齒等...

          g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, 
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);

          g.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, 
RenderingHints.VALUE_FRACTIONALMETRICS_ON);

          g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, 
RenderingHints.VALUE_ANTIALIAS_ON);

          g.setFont(new Font("Dialog", Font.PLAIN, 20));

          TextLayout tl = new TextLayout(text, g.getFont(), g.getFontRenderContext());

          Rectangle2D bounds = tl.getBounds();

          //計算文字要放置的位置

          double x = (im.getWidth()-bounds.getWidth()) - bounds.getX()-50;

          double y = (im.getHeight()-bounds.getHeight()) - bounds.getY()-80;

          //從綠色到紅色的漸層

          g.setPaint(new GradientPaint(0, 0, Color.GREEN, 30, 20, Color.RED, true));

      //寫入文字

          tl.draw(g, (float)x, (float)y);

          g.dispose();

      //輸出檔案

          java.io.FileOutputStream newimage = new java.io.FileOutputStream(

new java.io.File(FilePath+text+".jpg")); //輸出到文件流

              //  System.out.println("newimage:"+newimage);

             ImageIO.write(im, "JPEG", newimage);

             if(newimage!=null)

             {

               newimage.close();

               newimage = null ;

             }

    }

    //取得亂數

    public String getRnd(int length)

    {

      java.util.Random rnd = new java.util.Random();

      return getCode(rnd,length);

    }

    //取得亂數碼

    public String getCode(java.util.Random r,int num)

    {

      int rnd = 0;

      String authcode = "";

      for(int i = 0 ; i < num;i++)

      {

        if(getNumChar(r))

        {

          rnd = r.nextInt(9);

          authcode = authcode + rnd;

        }

        else

        {

          rnd = r.nextInt(52);

          if(rnd<26)

          {

            authcode = authcode +((char)(rnd +65));

          }

          else

          {

            authcode = authcode +((char)(rnd -26+ 97));

          }

        }

      }

      return authcode;

    }

    //八成數字二成英文

    //取得數字或字母

    public boolean getNumChar(java.util.Random r)

    {

      if(r.nextInt(100)>20)

        return true;

      else

        return false;

    }

    public static void main(String args[])throws Exception

    {

      CombineRndImg cri = new CombineRndImg();

      cri.run("d:/temp/","movie.jpg");

    }