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2016-06-17 06:09
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JAVA字符串Base64编码转换

已经得到了一个二进制的 byte[] encoded

想把这个encoded转换为Base64编码求教啊 最好把代码敲出来 谢谢了!!!!

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  • 丵鹰 2016-06-17 06:26
    已采纳
      BASE64Encoder base64 = new BASE64Encoder();
    
            String encodeStr3 = base64.encode(encoded);
    
    已采纳该答案
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  • little_how 2016-06-17 06:29

    import java.nio.charset.Charset;
    import java.util.Arrays;

    /**

    • 引用阿里巴巴fastjson中的base64工具
    • 自己实现encode方法
    • @author wh
    • @createtime 2015-11-19 上午11:48:38
      *
      */
      public class Base64 {
      public static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
      public static final int[] IA = new int[256];
      static {
      Arrays.fill(IA, -1);
      for (int i = 0, iS = CA.length; i < iS; i++)
      IA[CA[i]] = i;
      IA['='] = 0;
      }

      /**

      • Decodes a BASE64 encoded char array that is known to be resonably well formatted. The method is about twice as
      • fast as {@link #decode(char[])}. The preconditions are:
      • + The array must have a line length of 76 chars OR no line separators at all (one line).
      • + Line separator must be "\r\n", as specified in RFC 2045 + The array must not contain illegal characters within
      • the encoded string
      • + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.
      • @param chars The source array. Length 0 will return an empty array. null will throw an exception.
      • @return The decoded array of bytes. May be of length 0.
        */
        public final static byte[] decodeFast(char[] chars, int offset, int charsLen) {
        // Check special case
        if (charsLen == 0) {
        return new byte[0];
        }

        int sIx = offset, eIx = offset + charsLen - 1; // Start and end index after trimming.

        // Trim illegal chars from start
        while (sIx < eIx && IA[chars[sIx]] < 0)
        sIx++;

        // Trim illegal chars from end
        while (eIx > 0 && IA[chars[eIx]] < 0)
        eIx--;

        // get the padding count (=) (0, 1 or 2)
        int pad = chars[eIx] == '=' ? (chars[eIx - 1] == '=' ? 2 : 1) : 0; // Count '=' at end.
        int cCnt = eIx - sIx + 1; // Content count including possible separators
        int sepCnt = charsLen > 76 ? (chars[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;

        int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
        byte[] bytes = new byte[len]; // Preallocate byte[] of exact length

        // Decode all but the last 0 - 2 bytes.
        int d = 0;
        for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
        // Assemble three bytes into an int from four "valid" characters.
        int i = IA[chars[sIx++]] << 18 | IA[chars[sIx++]] << 12 | IA[chars[sIx++]] << 6 | IA[chars[sIx++]];

        // Add the bytes
        bytes[d++] = (byte) (i >> 16);
        bytes[d++] = (byte) (i >> 8);
        bytes[d++] = (byte) i;
        
        // If line separator, jump over it.
        if (sepCnt > 0 && ++cc == 19) {
            sIx += 2;
            cc = 0;
        }
        

        }

        if (d < len) {
        // Decode last 1-3 bytes (incl '=') into 1-3 bytes
        int i = 0;
        for (int j = 0; sIx <= eIx - pad; j++)
        i |= IA[chars[sIx++]] << (18 - j * 6);

        for (int r = 16; d < len; r -= 8)
            bytes[d++] = (byte) (i >> r);
        

        }

        return bytes;
        }

      public final static byte[] decodeFast(String chars, int offset, int charsLen) {
      // Check special case
      if (charsLen == 0) {
      return new byte[0];
      }

      int sIx = offset, eIx = offset + charsLen - 1; // Start and end index after trimming.
      
      // Trim illegal chars from start
      while (sIx < eIx && IA[chars.charAt(sIx)] < 0)
          sIx++;
      
      // Trim illegal chars from end
      while (eIx > 0 && IA[chars.charAt(eIx)] < 0)
          eIx--;
      
      // get the padding count (=) (0, 1 or 2)
      int pad = chars.charAt(eIx) == '=' ? (chars.charAt(eIx - 1) == '=' ? 2 : 1) : 0; // Count '=' at end.
      int cCnt = eIx - sIx + 1; // Content count including possible separators
      int sepCnt = charsLen > 76 ? (chars.charAt(76) == '\r' ? cCnt / 78 : 0) << 1 : 0;
      
      int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
      byte[] bytes = new byte[len]; // Preallocate byte[] of exact length
      
      // Decode all but the last 0 - 2 bytes.
      int d = 0;
      for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
          // Assemble three bytes into an int from four "valid" characters.
          int i = IA[chars.charAt(sIx++)] << 18 | IA[chars.charAt(sIx++)] << 12 | IA[chars.charAt(sIx++)] << 6 | IA[chars.charAt(sIx++)];
      
          // Add the bytes
          bytes[d++] = (byte) (i >> 16);
          bytes[d++] = (byte) (i >> 8);
          bytes[d++] = (byte) i;
      
          // If line separator, jump over it.
          if (sepCnt > 0 && ++cc == 19) {
              sIx += 2;
              cc = 0;
          }
      }
      
      if (d < len) {
          // Decode last 1-3 bytes (incl '=') into 1-3 bytes
          int i = 0;
          for (int j = 0; sIx <= eIx - pad; j++)
              i |= IA[chars.charAt(sIx++)] << (18 - j * 6);
      
          for (int r = 16; d < len; r -= 8)
              bytes[d++] = (byte) (i >> r);
      }
      
      return bytes;
      

      }

      /**

      • Decodes a BASE64 encoded string that is known to be resonably well formatted. The method is about twice as fast
      • as {@link #decode(String)}. The preconditions are:
      • + The array must have a line length of 76 chars OR no line separators at all (one line).
      • + Line separator must be "\r\n", as specified in RFC 2045 + The array must not contain illegal characters within
      • the encoded string
      • + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.
      • @param s The source string. Length 0 will return an empty array. null will throw an exception.
      • @return The decoded array of bytes. May be of length 0.
        */
        public final static byte[] decodeFast(String s) {
        // Check special case
        int sLen = s.length();
        if (sLen == 0) {
        return new byte[0];
        }

        int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.

        // Trim illegal chars from start
        while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0)
        sIx++;

        // Trim illegal chars from end
        while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0)
        eIx--;

        // get the padding count (=) (0, 1 or 2)
        int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2 : 1) : 0; // Count '=' at end.
        int cCnt = eIx - sIx + 1; // Content count including possible separators
        int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1 : 0;

        int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
        byte[] dArr = new byte[len]; // Preallocate byte[] of exact length

        // Decode all but the last 0 - 2 bytes.
        int d = 0;
        for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
        // Assemble three bytes into an int from four "valid" characters.
        int i = IA[s.charAt(sIx++)] << 18 | IA[s.charAt(sIx++)] << 12 | IA[s.charAt(sIx++)] << 6
        | IA[s.charAt(sIx++)];

        // Add the bytes
        dArr[d++] = (byte) (i >> 16);
        dArr[d++] = (byte) (i >> 8);
        dArr[d++] = (byte) i;
        
        // If line separator, jump over it.
        if (sepCnt > 0 && ++cc == 19) {
            sIx += 2;
            cc = 0;
        }
        

        }

        if (d < len) {
        // Decode last 1-3 bytes (incl '=') into 1-3 bytes
        int i = 0;
        for (int j = 0; sIx <= eIx - pad; j++)
        i |= IA[s.charAt(sIx++)] << (18 - j * 6);

        for (int r = 16; d < len; r -= 8)
            dArr[d++] = (byte) (i >> r);
        

        }

        return dArr;
        }

      // ############################# 以下不属于fast json base64 内容 ##########################
      public static String decode(String s){
      try {
      return new String(decodeFast(s), UTF8);
      } catch (Exception e) {
      return null;
      }
      }
      public static String decodeGbk(String s){
      try {
      return new String(decodeFast(s), GBK);
      } catch (Exception e) {
      return null;
      }
      }
      /** 编码方式 /
      public static final Charset UTF8 = Charset.forName("UTF-8");
      public static final Charset GBK = Charset.forName("GBK");
      /
      *

      • 按照utf-8编码字符
      • @param s -- 待编码字符
      • @return */ public static String encode(String s){ try{ return encode(s.getBytes(UTF8)); }catch(Exception e){ e.printStackTrace(); return null; } }

      /**

      • 按照gbk解码字符
      • @param s
      • @return */ public static String encodeGbk(String s){ try{ return encode(s.getBytes(GBK)); }catch(Exception e){ e.printStackTrace(); return null; } }

      /**

      • base编码
      • @param target
      • @return / public static String encode(byte[] target){ if(target==null||target.length==0) return null; int length = target.length; /* 判断最后补位数 / int replenish = length%3; /* 判断target长度是否为总循环次数 / int loop = length/3 + (replenish==0?0:1); byte[] ret = new byte[4 * loop]; /* 下标 */ int index = 0; int retIndex = 0; int one,two,three; while((--loop)>0){ one = target[index++] & 0xff; two = target[index++] & 0xff; three = target[index++] & 0xff; ret[retIndex++] = (byte)CA[one>>>2&0x3f]; ret[retIndex++] = (byte)CA[(one<>>4)&0x3f]; ret[retIndex++] = (byte)CA[(two<>>6)&0x3f]; ret[retIndex++] = (byte)CA[three&0x3f]; } //判断最后是否还有剩余,有补等号的情况出现 switch(replenish){ case 0: one = target[index++] & 0xff; two = target[index++] & 0xff; three = target[index++] & 0xff; ret[retIndex++] = (byte)CA[one>>>2&0x3f]; ret[retIndex++] = (byte)CA[(one<>>4)&0x3f]; ret[retIndex++] = (byte)CA[(two<>>6)&0x3f]; ret[retIndex++] = (byte)CA[three&0x3f]; break; case 1://补两个= one = target[length-1] & 0xff; ret[retIndex++] = (byte)CA[one>>>2&0x3f]; ret[retIndex++] = (byte)CA[one<>>2&0x3f]; ret[retIndex++] = (byte)CA[(one<>>4)&0x3f]; ret[retIndex++] = (byte)CA[two<<2 & 0x3f]; ret[retIndex++] = (byte) '='; break; } return new String(ret); } }

    我上传了一个资源,编解码base64的,现在还没出地址,到时候出地址了
    再给你贴上了,或者你复制我的代码进类也可以。

    如果有帮助,希望结帖

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  • little_how 2016-06-17 06:32

    我把那个类写成博客了,你可以看看
    http://blog.csdn.net/w172087242/article/details/51699731

    如果有帮助,希望结帖

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    打赏 举报

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