java 图片 背景 透明

package com.picture;

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.regex.Pattern;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane;

public class Picture {

	public static void convert(String path) {
		// TODO Auto-generated constructor stub
		try {
			BufferedImage image = ImageIO.read(new File(path));
			ImageIcon imageIcon = new ImageIcon(image);
			BufferedImage bufferedImage = new BufferedImage(
					imageIcon.getIconWidth(), imageIcon.getIconHeight(),
					BufferedImage.TYPE_4BYTE_ABGR);
			Graphics2D g2D = (Graphics2D) bufferedImage.getGraphics();
			g2D.drawImage(imageIcon.getImage(), 0, 0,
					imageIcon.getImageObserver());
			int alpha = 0;
			for (int j1 = bufferedImage.getMinY(); j1 < bufferedImage
					.getHeight(); j1++) {
				for (int j2 = bufferedImage.getMinX(); j2 < bufferedImage
						.getWidth(); j2++) {
					int rgb = bufferedImage.getRGB(j2, j1);
					if (colorInRange(rgb))
						alpha = 0;
					else
						alpha = 255;
					rgb = (alpha << 24) | (rgb & 0x00ffffff);
					bufferedImage.setRGB(j2, j1, rgb);
				}
			}
			g2D.drawImage(bufferedImage, 0, 0, imageIcon.getImageObserver());
			// 生成图片为PNG
			String outFile = path.substring(0, path.lastIndexOf("."));
			ImageIO.write(bufferedImage, "png", new File(outFile + ".png"));
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

    public static int color_range = 210;
	public static boolean colorInRange(int color) {
		int red = (color & 0xff0000) >> 16;
		int green = (color & 0x00ff00) >> 8;
		int blue = (color & 0x0000ff);
		if (red >= color_range && green >= color_range && blue >= color_range)
			return true;
		return false;
	}
}