問題描述
使用 GZIPOutputStream 壓縮字符串 (Compressing a string using GZIPOutputStream)
I want to zip my string values. These string values should be same as .net zipped strings.
I wrote Decompress method and when I send a .net zipped string to it, it works correctly. But the Compress method does not work correctly.
<pre class="lang-java prettyprint-override">public static String Decompress(String zipText) throws IOException {
int size = 0;
byte[] gzipBuff = Base64.decode(zipText);
ByteArrayInputStream memstream = new ByteArrayInputStream(gzipBuff, 4,
gzipBuff.length - 4);
GZIPInputStream gzin = new GZIPInputStream(memstream);
final int buffSize = 8192;
byte[] tempBuffer = new byte[buffSize];
ByteArrayOutputStream baos = new ByteArrayOutputStream();
while ((size = gzin.read(tempBuffer, 0, buffSize)) != -1) {
baos.write(tempBuffer, 0, size);
}
byte[] buffer = baos.toByteArray();
baos.close();
return new String(buffer, "UTF-8");
}
</code></pre>
<pre class="lang-java prettyprint-override">public static String Compress(String text) throws IOException {
byte[] gzipBuff = EncodingUtils.getBytes(text, "UTF-8");
ByteArrayOutputStream bs = new ByteArrayOutputStream();
GZIPOutputStream gzin = new GZIPOutputStream(bs);
gzin.write(gzipBuff);
gzin.finish();
bs.close();
byte[] buffer = bs.toByteArray();
gzin.close();
return Base64.encode(buffer);
}
</code></pre>
For example when I send "BQAAAB+LCAAAAAAABADtvQdgHEmWJSYvbcp7f0r1StfgdKEIgGATJNiQQBDswYjN5pLsHWlHIymrKoHKZVZlXWYWQMztnbz33nvvvffee++997o7nU4n99//P1xmZAFs9s5K2smeIYCqyB8/fnwfPyLmeVlW/w+GphA2BQAAAA==" to Decompress method It returns the string "Hello", but when I send "Hello" to Compress method It returns "H4sIAAAAAAAAAMtIzcnJBwCGphA2BQAAAA==".
What is the problem in Compress method????
參考解法
方法 1:
Check Use Zip Stream and Base64 Encoder to Compress Large String Data
about how to use GZIPOutputStream/GZIInputStream and Base64 Encoder and Decoder to compress and uncompress large string data, so it can be passed as text in http response.
public static String compressString(String srcTxt) throws IOException {
ByteArrayOutputStream rstBao = new ByteArrayOutputStream();
GZIPOutputStream zos = new GZIPOutputStream(rstBao);
zos.write(srcTxt.getBytes());
IOUtils.closeQuietly(zos);
byte[] bytes = rstBao.toByteArray();
return Base64.encodeBase64String(bytes);
}
Or we can use Use Zip Stream and Base64 Encoder to Compress Large String Data to avoid load whole string into memory.
public static String uncompressString(String zippedBase64Str) throws IOException {
String result = null;
byte[] bytes = Base64.decodeBase64(zippedBase64Str);
GZIPInputStream zi = null;
try {
zi = new GZIPInputStream(new ByteArrayInputStream(bytes));
result = IOUtils.toString(zi);
} finally {
IOUtils.closeQuietly(zi);
}
return result;
}
方法 2:
I have tried with java vm i suppose the result is the same. Use this line at the end of your Compress method :
return new String(base64.encode(buffer), "UTF-8");
(by Bobs、JeffersonZhang、revo)
參考文件