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！！！！

  BASE64Encoder base64 = new BASE64Encoder();

        String encodeStr3 = base64.encode(encoded);

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

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