Java之Base64工具类

Base64

一组由Base64编码组成的字符串,我们将其称之为"Base64编码"。

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.Hashtable;
 
import org.apache.commons.codec.binary.Base64;
 
import Decoder.BASE64Decoder;
 
import com.alibaba.fastjson.JSONObject;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
 
/**
 * Base64处理类
 */
public class Base64Util {
 
	/**
	 * 将base64格式的图片转换成本地图片文件
	 * 
	 * @method base64ToFileByte
	 * @param fileJson
	 *            base64字符串
	 * @param fileName
	 *            本地临时文件名(如1.png)
	 * @return File 本地临时文件
	 * @throws Exception
	 */
	public static File base64ToFile(String fileJson, String fileName)
			throws Exception {
		String prvPath = Thread.currentThread().getContextClassLoader()
				.getResource("/").getPath();
		String path = prvPath.substring(1, prvPath.indexOf("classes"))
				+ "temp/";
		String tempPath = path + fileName;
		File file = new File(path);
		if (!file.exists()) {
			file.mkdirs();
		}
		file = new File(tempPath);
		if (file.exists()) {
			file.delete();
		}
		Base64 base64 = new Base64();
		byte[] b = base64.decode(fileJson);
		OutputStream out = new FileOutputStream(file);
		out.write(b);
		out.flush();
		out.close();
		return file;
	}
 
	/**
	 * 将指定信息写入base64字符串
	 * 
	 * @method toBase64
	 * @param contents
	 * @param width
	 * @param height
	 * @return
	 * @throws Exception
	 */
	public static String toBase64(JSONObject obj, int width, int height)
			throws Exception {
		Hashtable<Object, Object> hints = new Hashtable<Object, Object>();
		// 指定纠错等级
		hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);
		// 指定编码格式
		BitMatrix byteMatrix = new MultiFormatWriter().encode(new String(obj
				.toJSONString().getBytes("UTF-8"), "iso-8859-1"),
				BarcodeFormat.QR_CODE, width, height);
		ByteArrayOutputStream bao = new ByteArrayOutputStream();
		MatrixToImageWriter.writeToStream(byteMatrix, "png", bao);
		String ok = Base64Code(bao.toByteArray());
		bao.flush();
		bao.close();
		return ok;
	}
 
	/**
	 * base64加密
	 * @method Base64Code
	 * @param b
	 * @return
	 */
	public static String Base64Code(byte[] b) {
		Base64 encoder = new Base64();
		StringBuilder pictureBuffer = new StringBuilder();
		pictureBuffer.append(encoder.encodeAsString(b));
		String codeBase64 = pictureBuffer.toString();
		return codeBase64;
	}
 
	// base64字符串转化成图片
	public static boolean GenerateImage(String imgStr) { // 对字节数组字符串进行Base64解码并生成图片
		if (imgStr == null) // 图像数据为空
			return false;
		BASE64Decoder decoder = new BASE64Decoder();
		try {
			// Base64解码
			byte[] b = decoder.decodeBuffer(imgStr);
			for (int i = 0; i < b.length; ++i) {
				if (b[i] < 0) {// 调整异常数据
					b[i] += 256;
				}
			}
			// 生成jpeg图片
			String imgFilePath = "D:\\test.jpg";// 新生成的图片
			OutputStream out = new FileOutputStream(imgFilePath);
			out.write(b);
			out.flush();
			out.close();
			return true;
		} catch (Exception e) {
			return false;
		}
	}
 
	public static void main(String[] args) {
		try {
			JSONObject jsonObject = new JSONObject();
			jsonObject.put("QQ", "1000");
			jsonObject.put("昵称", "猫猫");
			String str = Base64Util.toBase64(jsonObject, 150, 150);
			GenerateImage(str);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}