Java LZMA 字符串压缩解压

/* from: https://hacpai.com/article/1481701879422/comment/1481871510461 */

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Base64;




public static String lzma(final String str) throws IOException {
    if (str == null || "".equals(str)) {
        return str;
    }

    final SevenZip.Compression.LZMA.Encoder encoder = new SevenZip.Compression.LZMA.Encoder();

    final ByteArrayOutputStream out = new ByteArrayOutputStream();
    final ByteArrayInputStream in = new ByteArrayInputStream(str.getBytes());

    try {
        encoder.SetEndMarkerMode(false);
        encoder.WriteCoderProperties(out);
        final long fileSize = in.available();
        for (int i = 0; i < 8; i++) {
            out.write((int) (fileSize >>> (8 * i)) & 0xFF);
        }
        encoder.Code(in, out, -1, -1, null);

        final byte[] compressed = out.toByteArray();

        byte[] b64 = Base64.getEncoder().encode(compressed);
        return new String(b64, "UTF-8");
    } finally {
        IOUtils.closeQuietly(in);
        IOUtils.closeQuietly(out);
    }
}

public static String unlzma(final String compressedStr) throws IOException {
    if (null == compressedStr || "".equals(compressedStr)) {
        return compressedStr;
    }

    final SevenZip.Compression.LZMA.Decoder decoder = new SevenZip.Compression.LZMA.Decoder();

    final ByteArrayOutputStream out = new ByteArrayOutputStream();
    final ByteArrayInputStream in = new ByteArrayInputStream(Base64.getDecoder().decode(compressedStr));

    try {
        final int propertiesSize = 5;
        final byte[] properties = new byte[propertiesSize];
        if (in.read(properties, 0, propertiesSize) != propertiesSize) {
            throw new IOException("input .lzma file is too short");
        }
        if (!decoder.SetDecoderProperties(properties)) {
            throw new IOException("Incorrect stream properties");
        }
        long outSize = 0;
        for (int i = 0; i < 8; i++) {
            final int v = in.read();
            if (v < 0) {
                throw new IOException("Can't read stream size");
            }
            outSize |= ((long) v) << (8 * i);
        }
        if (!decoder.Code(in, out, outSize)) {
            throw new IOException("Error in data stream");
        }

        return out.toString("UTF-8");
    } finally {
        IOUtils.closeQuietly(in);
        IOUtils.closeQuietly(out);
    }
}