• Android和服务端数据交互使用压缩


    公司一个用户数据过大,导致android与服务端通讯速度太慢,通过分析,最小改动方式使用数据压缩,不压缩前数据大概5M压缩后只有20k.

    服务端使用gzip压缩。客户端androi使用类解压缩,在网上找了一个工具类如下。解决。

    public final class Base64Utils {
        private static final int BASELENGTH = 128;
        private static final int LOOKUPLENGTH = 64;
        private static final int TWENTYFOURBITGROUP = 24;
        private static final int EIGHTBIT = 8;
        private static final int SIXTEENBIT = 16;
        private static final int SIXBIT = 6;
        private static final int FOURBYTE = 4;
        private static final int SIGN = -128;
        private static final char PAD = '=';
        private static final boolean fDebug = false;
        private static final byte[] base64Alphabet = new byte[128];
        private static final char[] lookUpBase64Alphabet = new char[64];
    
        public Base64Utils() {
        }
    
        protected static boolean isWhiteSpace(char octect) {
            return octect == 32 || octect == 13 || octect == 10 || octect == 9;
        }
    
        protected static boolean isPad(char octect) {
            return octect == 61;
        }
    
        protected static boolean isData(char octect) {
            return octect < 128 && base64Alphabet[octect] != -1;
        }
    
        protected static boolean isBase64(char octect) {
            return isWhiteSpace(octect) || isPad(octect) || isData(octect);
        }
    
        public static String encode(byte[] binaryData) {
            if(binaryData == null) {
                return null;
            } else {
                int lengthDataBits = binaryData.length * 8;
                if(lengthDataBits == 0) {
                    return "";
                } else {
                    int fewerThan24bits = lengthDataBits % 24;
                    int numberTriplets = lengthDataBits / 24;
                    int numberQuartet = fewerThan24bits != 0?numberTriplets + 1:numberTriplets;
                    Object encodedData = null;
                    char[] var17 = new char[numberQuartet * 4];
                    boolean k = false;
                    boolean l = false;
                    boolean b1 = false;
                    boolean b2 = false;
                    boolean b3 = false;
                    int encodedIndex = 0;
                    int dataIndex = 0;
    
                    byte val2;
                    byte var18;
                    byte var19;
                    byte var20;
                    byte var21;
                    for(int val1 = 0; val1 < numberTriplets; ++val1) {
                        var20 = binaryData[dataIndex++];
                        var21 = binaryData[dataIndex++];
                        byte var22 = binaryData[dataIndex++];
                        var19 = (byte)(var21 & 15);
                        var18 = (byte)(var20 & 3);
                        val2 = (var20 & -128) == 0?(byte)(var20 >> 2):(byte)(var20 >> 2 ^ 192);
                        byte val21 = (var21 & -128) == 0?(byte)(var21 >> 4):(byte)(var21 >> 4 ^ 240);
                        byte val3 = (var22 & -128) == 0?(byte)(var22 >> 6):(byte)(var22 >> 6 ^ 252);
                        var17[encodedIndex++] = lookUpBase64Alphabet[val2];
                        var17[encodedIndex++] = lookUpBase64Alphabet[val21 | var18 << 4];
                        var17[encodedIndex++] = lookUpBase64Alphabet[var19 << 2 | val3];
                        var17[encodedIndex++] = lookUpBase64Alphabet[var22 & 63];
                    }
    
                    byte var23;
                    if(fewerThan24bits == 8) {
                        var20 = binaryData[dataIndex];
                        var18 = (byte)(var20 & 3);
                        var23 = (var20 & -128) == 0?(byte)(var20 >> 2):(byte)(var20 >> 2 ^ 192);
                        var17[encodedIndex++] = lookUpBase64Alphabet[var23];
                        var17[encodedIndex++] = lookUpBase64Alphabet[var18 << 4];
                        var17[encodedIndex++] = 61;
                        var17[encodedIndex++] = 61;
                    } else if(fewerThan24bits == 16) {
                        var20 = binaryData[dataIndex];
                        var21 = binaryData[dataIndex + 1];
                        var19 = (byte)(var21 & 15);
                        var18 = (byte)(var20 & 3);
                        var23 = (var20 & -128) == 0?(byte)(var20 >> 2):(byte)(var20 >> 2 ^ 192);
                        val2 = (var21 & -128) == 0?(byte)(var21 >> 4):(byte)(var21 >> 4 ^ 240);
                        var17[encodedIndex++] = lookUpBase64Alphabet[var23];
                        var17[encodedIndex++] = lookUpBase64Alphabet[val2 | var18 << 4];
                        var17[encodedIndex++] = lookUpBase64Alphabet[var19 << 2];
                        var17[encodedIndex++] = 61;
                    }
    
                    return new String(var17);
                }
            }
        }
    
        public static byte[] decode(String encoded) {
            if(encoded == null) {
                return null;
            } else {
                char[] base64Data = encoded.toCharArray();
                int len = removeWhiteSpace(base64Data);
                if(len % 4 != 0) {
                    return null;
                } else {
                    int numberQuadruple = len / 4;
                    if(numberQuadruple == 0) {
                        return new byte[0];
                    } else {
                        Object decodedData = null;
                        boolean b1 = false;
                        boolean b2 = false;
                        boolean b3 = false;
                        boolean b4 = false;
                        boolean d1 = false;
                        boolean d2 = false;
                        boolean d3 = false;
                        boolean d4 = false;
                        int i = 0;
                        int encodedIndex = 0;
                        int dataIndex = 0;
    
                        byte[] var17;
                        byte var18;
                        byte var19;
                        byte var20;
                        byte var21;
                        char var22;
                        char var23;
                        char var24;
                        char var25;
                        for(var17 = new byte[numberQuadruple * 3]; i < numberQuadruple - 1; ++i) {
                            if(!isData(var22 = base64Data[dataIndex++]) || !isData(var23 = base64Data[dataIndex++]) || !isData(var24 = base64Data[dataIndex++]) || !isData(var25 = base64Data[dataIndex++])) {
                                return null;
                            }
    
                            var18 = base64Alphabet[var22];
                            var19 = base64Alphabet[var23];
                            var20 = base64Alphabet[var24];
                            var21 = base64Alphabet[var25];
                            var17[encodedIndex++] = (byte)(var18 << 2 | var19 >> 4);
                            var17[encodedIndex++] = (byte)((var19 & 15) << 4 | var20 >> 2 & 15);
                            var17[encodedIndex++] = (byte)(var20 << 6 | var21);
                        }
    
                        if(isData(var22 = base64Data[dataIndex++]) && isData(var23 = base64Data[dataIndex++])) {
                            var18 = base64Alphabet[var22];
                            var19 = base64Alphabet[var23];
                            var24 = base64Data[dataIndex++];
                            var25 = base64Data[dataIndex++];
                            if(isData(var24) && isData(var25)) {
                                var20 = base64Alphabet[var24];
                                var21 = base64Alphabet[var25];
                                var17[encodedIndex++] = (byte)(var18 << 2 | var19 >> 4);
                                var17[encodedIndex++] = (byte)((var19 & 15) << 4 | var20 >> 2 & 15);
                                var17[encodedIndex++] = (byte)(var20 << 6 | var21);
                                return var17;
                            } else {
                                byte[] tmp;
                                if(isPad(var24) && isPad(var25)) {
                                    if((var19 & 15) != 0) {
                                        return null;
                                    } else {
                                        tmp = new byte[i * 3 + 1];
                                        System.arraycopy(var17, 0, tmp, 0, i * 3);
                                        tmp[encodedIndex] = (byte)(var18 << 2 | var19 >> 4);
                                        return tmp;
                                    }
                                } else if(!isPad(var24) && isPad(var25)) {
                                    var20 = base64Alphabet[var24];
                                    if((var20 & 3) != 0) {
                                        return null;
                                    } else {
                                        tmp = new byte[i * 3 + 2];
                                        System.arraycopy(var17, 0, tmp, 0, i * 3);
                                        tmp[encodedIndex++] = (byte)(var18 << 2 | var19 >> 4);
                                        tmp[encodedIndex] = (byte)((var19 & 15) << 4 | var20 >> 2 & 15);
                                        return tmp;
                                    }
                                } else {
                                    return null;
                                }
                            }
                        } else {
                            return null;
                        }
                    }
                }
            }
        }
    
        protected static int removeWhiteSpace(char[] data) {
            if(data == null) {
                return 0;
            } else {
                int newSize = 0;
                int len = data.length;
    
                for(int i = 0; i < len; ++i) {
                    if(!isWhiteSpace(data[i])) {
                        data[newSize++] = data[i];
                    }
                }
    
                return newSize;
            }
        }
    
        static {
            int i;
            for(i = 0; i < 128; ++i) {
                base64Alphabet[i] = -1;
            }
    
            for(i = 90; i >= 65; --i) {
                base64Alphabet[i] = (byte)(i - 65);
            }
    
            for(i = 122; i >= 97; --i) {
                base64Alphabet[i] = (byte)(i - 97 + 26);
            }
    
            for(i = 57; i >= 48; --i) {
                base64Alphabet[i] = (byte)(i - 48 + 52);
            }
    
            base64Alphabet[43] = 62;
            base64Alphabet[47] = 63;
    
            for(i = 0; i <= 25; ++i) {
                lookUpBase64Alphabet[i] = (char)(65 + i);
            }
    
            i = 26;
    
            int j;
            for(j = 0; i <= 51; ++j) {
                lookUpBase64Alphabet[i] = (char)(97 + j);
                ++i;
            }
    
            i = 52;
    
            for(j = 0; i <= 61; ++j) {
                lookUpBase64Alphabet[i] = (char)(48 + j);
                ++i;
            }
    
            lookUpBase64Alphabet[62] = 43;
            lookUpBase64Alphabet[63] = 47;
        }
    
    CompressUtils.java
    
    public static String compresss(String str){
        if (str == null || str.length() == 0) {
            return str;
        }
        String outStr = "";
        try {
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            GZIPOutputStream gzip = new GZIPOutputStream(out);
            gzip.write(str.getBytes());
            gzip.close();
            outStr = new String(Base64Utils.encode(out.toByteArray()));
        }catch (Exception e){
            e.printStackTrace();
        }
        return outStr;
    }
    
    public static String decompresss(String str) throws IOException {
        if (str == null || str.length() == 0) {
            return str;
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try {
            GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(Base64Utils.decode(str)));
            String outStr = "";
            byte[] buffer = new byte[256];
            int n;
            while ((n = gis.read(buffer)) >= 0) {
                out.write(buffer, 0, n);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        return new String(out.toByteArray());
    }
    
    ————————————————
    版权声明:本文为CSDN博主「abs625」的原创文章,遵循CC 4.0 BY-SA版权协议,转载请附上原文出处链接及本声明。
    原文链接:https://blog.csdn.net/abs625/article/details/76552576
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  • 原文地址:https://www.cnblogs.com/zhaogaojian/p/12869765.html
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