// 对字符串进行压缩
public static String lzma(String input) throws IOException {
InputStream in = new ByteArrayInputStream(input.getBytes(StandardCharsets.UTF_8));
LZMA2Options options = new LZMA2Options();
options.setPreset(7); // play with this number: 6 is default but 7 works better for mid sized archives ( > 8mb)
ByteArrayOutputStream out = new ByteArrayOutputStream();
XZOutputStream xzOutputStream = new XZOutputStream(out, options);
byte[] buf = new byte[8192];
int size;
while ((size = in.read(buf)) != -1)
xzOutputStream.write(buf, 0, size);
xzOutputStream.finish();
return new String(out.toByteArray());
}