package com.wmly.enc; import java.util.HashMap; /**  * 128进制加解密, 一个符号可表示7个bit  * 可以自定义符号表, 符号不能重复  */ public class MyBASE128 {  public static final char[] symbolTable = new char[128];  public static final HashMap<Character, Integer> indexTable = new HashMap<>(128);  static {   int i = 0;   for (int j = 0; j < 128; j++) { //   symbolTable[j] = (char) j;    if('A' <= j && j <= 'Z'     || 'a' <= j && j <= 'z'     || '0' <= j && j <= '9') {     symbolTable[i++] = (char) j;    }   }   for (char c : "这是中国人写地[备思要爱发]编解码程序&拥有独特的自定义符号表|不过布能使用重复字,汗啊(还差一十二个知*.#)。为我们加油吧，亲！".toCharArray()) {    symbolTable[i++] = c;   }   checkTable();   for (int j = 0; j < 128; j++) {    indexTable.put(symbolTable[j], j);   }  }  private static void checkTable() throws Error {   if(symbolTable[127] == 0) {    throw new Error("符号表长度不正确！");   }   for (char a : symbolTable) {    int count = 0;    for (char b : symbolTable) {     if(a == b) {      count++;     }    }    if(count > 2) {     throw new Error("符号表有重复符号！");    }   }  }  public String encode(byte[] data) {   if(data == null || data.length == 0) {    return new String();   }   StringBuilder result = new StringBuilder();   int tail = 0;   for (int i = 0; i < data.length; i++) {    int mov = (i % 7 + 1);    int curr = 0xFF & data[i];    int code = tail + (curr >> mov);    result.append(symbolTable[code]);    tail = (0xFF & (curr << (8 - mov))) >> 1;    if(mov == 7) {     result.append(symbolTable[tail]);     tail = 0;    }   }   result.append(symbolTable[tail]);   return result.toString();  }  public byte[] decode(String base128) {   if(base128 == null || base128.length() == 0) {    return new byte[] { };   }   int length = (int) Math.floor(base128.length() * 0.875);   byte[] result = new byte[length];   int idx = 0;   int head = indexTable.get(base128.charAt(0)) << 1;   for (int i = 1; i < base128.length();) {    int mod = i % 8;    int code = indexTable.get(base128.charAt(i++));    result[idx++] = (byte) (0xFF & (head + (code >> (7 - mod))));    if(mod == 7) {     head = 0xFF & (indexTable.get(base128.charAt(i++)) << 1);    } else {     head = 0xFF & (code << (mod + 1));    }   }   return result;  }  ///////////////////////测试方法///////////////////////////////  public static void main(String[] args) {   MyBASE128 base128 = new MyBASE128();   test(base128);   String txt = "这是我的加解密测试";   String enc = base128.encode(txt.getBytes());   System.out.println(enc);   System.out.println("----------------");   System.out.println(new String(base128.decode(enc)));  }  private static void test(MyBASE128 base128) {   for (int i = 0; i < 10000; i++) {    String r = randomData();    String d = new String(base128.decode(base128.encode(r.getBytes())));    if(!r.equals(d)) { //    d = new String(base128.decode(base128.encode(r.getBytes())));     System.out.println("加解密失败！: " + r);    }   }  }  private static String randomData() {   String textString = "了咖啡机累啊戴假发\n\r哦-";   int start = random(0, textString.length() - 3);   int end = random(start + 1, textString.length() - 1);   return textString.substring(start, end);  }  private static int random(int i, int j) {   return (int) Math.ceil(Math.random()*(j-i)+i);  } }