Base64Utils.java

package com.camnter.newlife.utils;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Base64;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Description：Base64Utils
 * Created by：CaMnter
 * Time：2015-12-06 17:54
 */
public class Base64Utils {

    private static final char[] legalChars
        = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();


    /**
     * Base64 encode the given data
     */
    public static String encode(byte[] data) {
        int start = 0;
        int len = data.length;
        StringBuffer buf = new StringBuffer(data.length * 3 / 2);
        int end = len - 3;
        int i = start;
        // int n = 0;
        while (i <= end) {
            int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 0x0ff) << 8) |
                (((int) data[i + 2]) & 0x0ff);

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append(legalChars[(d >> 6) & 63]);
            buf.append(legalChars[d & 63]);

            i += 3;

      /*
       * if (n++ >= 14) { n = 0; buf.append(" "); }
       */

        }

        if (i == start + len - 2) {
            int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 255) << 8);

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append(legalChars[(d >> 6) & 63]);
            buf.append("=");
        } else if (i == start + len - 1) {
            int d = (((int) data[i]) & 0x0ff) << 16;

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append("==");
        }
        return buf.toString();
    }


    /**
     * Decodes the given Base64 encoded String to a new byte array. The byte array holding the
     * decoded data is returned.
     */

    public static byte[] decode(String s) {

        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try {
            decode(s, bos);
        } catch (IOException e) {
            throw new RuntimeException();
        }
        byte[] decodedBytes = bos.toByteArray();
        try {
            bos.close();
            bos = null;
        } catch (IOException ex) {
            System.err.println("Error while decoding BASE64: " + ex.toString());
        }
        return decodedBytes;
    }


    private static int decode(char c) {
        if (c >= 'A' && c <= 'Z') {
            return ((int) c) - 65;
        } else if (c >= 'a' && c <= 'z') {
            return ((int) c) - 97 + 26;
        } else if (c >= '0' && c <= '9') {
            return ((int) c) - 48 + 26 + 26;
        } else {
            switch (c) {
                case '+':
                    return 62;
                case '/':
                    return 63;
                case '=':
                    return 0;
                default:
                    throw new RuntimeException("unexpected code: " + c);
            }
        }
    }


    private static void decode(String s, OutputStream os) throws IOException {
        int i = 0;
        int len = s.length();
        while (true) {
            while (i < len && s.charAt(i) <= ' ') {
                i++;
            }
            if (i == len) {
                break;
            }
            int tri = (decode(s.charAt(i)) << 18) + (decode(s.charAt(i + 1)) << 12) +
                (decode(s.charAt(i + 2)) << 6) + (decode(s.charAt(i + 3)));
            os.write((tri >> 16) & 255);
            if (s.charAt(i + 2) == '=') {
                break;
            }
            os.write((tri >> 8) & 255);
            if (s.charAt(i + 3) == '=') {
                break;
            }
            os.write(tri & 255);

            i += 4;
        }
    }


    /**
     * bitmap转成base64
     *
     * @param bitmap bitmap
     * @return base64
     */
    public String bitmapToBase64(Bitmap bitmap) {
        // 将Bitmap转换成字符串
        String base64;
        ByteArrayOutputStream bStream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, bStream);
        byte[] bytes = bStream.toByteArray();
        base64 = Base64.encodeToString(bytes, Base64.DEFAULT);
        return base64;
    }


    /**
     * base64转成bitmap
     *
     * @param base64 base64
     * @return bitmap
     */
    public Bitmap base64ToBitmap(String base64) {
        // 将字符串转换成Bitmap类型
        Bitmap bitmap = null;
        try {
            byte[] bitmapArray;
            bitmapArray = Base64.decode(base64, Base64.DEFAULT);
            bitmap = BitmapFactory.decodeByteArray(bitmapArray, 0, bitmapArray.length);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return bitmap;
    }
}