首先是要生成驗證碼:
package XX.XX
import java.io.*;
import java.util.*;
import javax.imageio.*;
import java.awt.*;
import java.awt.image.*;
public class ImageEnsure ...{
public ImageEnsure() ...{
}
private char mapTable[] = ...{'0', '1', '2', '3',
'4', '5', '6', '7', '8', '9'};
public String getEnsure(int width, int height, OutputStream os) ...{
if (width <= 0)
width = 60;
if (height <= 0)
height = 20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 獲取圖形上下文
Graphics g = image.getGraphics();
// 設定背景色
g.setColor(new Color(0xDCCCCC));
g.fillRect(0, 0, width, height);
//畫邊框
g.setColor(Color.black);
g.drawRect(0, 0, width - 1, height - 1);
// 取隨機產生的認證碼
String strEnsure = "";
// 4代表4位驗證碼
for (int i = 0; i < 4; ++i) ...{
strEnsure += mapTable[(int) (mapTable.length * Math.random())];
}
// 將認證碼顯示到圖象中
g.setColor(Color.red);
g.setFont(new Font("Atlantic Inline", Font.PLAIN, 14));
//畫的具體坐標
String str = strEnsure.substring(0, 1);
g.drawString(str, 8, 14);
str = strEnsure.substring(1, 2);
g.drawString(str, 20, 15);
str = strEnsure.substring(2, 3);
g.drawString(str, 35, 18);
str = strEnsure.substring(3, 4);
g.drawString(str, 45, 15);
// 釋放圖形上下文
g.dispose();
try ...{
// 輸出圖象到頁面
ImageIO.write(image, "JPEG", os);
} catch (IOException e) ...{
return "";
}
return strEnsure;
}
}