Base64类 源码

 Base64.java 源码:

import java.io.*; 
  
public class Base64 { 
    private static char[] base64EncodeChars = new char[] { 
        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 
        'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 
        'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 
        'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 
        'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 
        'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 
        'w', 'x', 'y', 'z', '0', '1', '2', '3', 
        '4', '5', '6', '7', '8', '9', '+', '/' }; 
  
    private static byte[] base64DecodeChars = new byte[] { 
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, 
    -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, 
    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 }; 
  
    public static String encode(byte[] data) { 
        StringBuffer sb = new StringBuffer(); 
        int len = data.length; 
        int i = 0; 
        int b1, b2, b3; 
        while (i < len) { 
            b1 = data[i++] & 0xff; 
            if (i == len) 
            { 
                sb.append(base64EncodeChars[b1 >>> 2]); 
                sb.append(base64EncodeChars[(b1 & 0x3) << 4]); 
                sb.append("=="); 
                break; 
            } 
            b2 = data[i++] & 0xff; 
            if (i == len) 
            { 
                sb.append(base64EncodeChars[b1 >>> 2]); 
                sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]); 
                sb.append(base64EncodeChars[(b2 & 0x0f) << 2]); 
                sb.append("="); 
                break; 
            } 
            b3 = data[i++] & 0xff; 
            sb.append(base64EncodeChars[b1 >>> 2]); 
            sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]); 
            sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]); 
            sb.append(base64EncodeChars[b3 & 0x3f]); 
        } 
        return sb.toString(); 
    } 
  
    public static byte[] decode(String str) throws UnsupportedEncodingException { 
        StringBuffer sb = new StringBuffer(); 
        byte[] data = str.getBytes("US-ASCII"); 
        int len = data.length; 
        int i = 0; 
        int b1, b2, b3, b4; 
        while (i < len) { 
            /* b1 */ 
            do { 
                b1 = base64DecodeChars[data[i++]]; 
            } while (i < len && b1 == -1); 
            if (b1 == -1) break; 
            /* b2 */ 
            do { 
                b2 = base64DecodeChars[data[i++]]; 
            } while (i < len && b2 == -1); 
            if (b2 == -1) break; 
            sb.append((char)((b1 << 2) | ((b2 & 0x30) >>> 4))); 
            /* b3 */ 
            do { 
                b3 = data[i++]; 
                if (b3 == 61) return sb.toString().getBytes("ISO-8859-1"); 
                b3 = base64DecodeChars[b3]; 
            } while (i < len && b3 == -1); 
            if (b3 == -1) break; 
            sb.append((char)(((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2))); 
            /* b4 */ 
            do { 
                b4 = data[i++]; 
                if (b4 == 61) return sb.toString().getBytes("ISO-8859-1"); 
                b4 = base64DecodeChars[b4]; 
            } while (i < len && b4 == -1); 
            if (b4 == -1) break; 
            sb.append((char)(((b3 & 0x03) << 6) | b4)); 
        } 
        return sb.toString().getBytes("ISO-8859-1"); 
    } 
} 

TestBase64.java 

public class TestBase64 {
	public static void main(String[] args) {
		String s = Base64.encode("wepull1107".getBytes());   //将wepull1107转化为Base64编码
		System.out.println(s);
				
	}
}