我一直在试图理解如何使用 GZIPOutputStream
等内容,但是没有成功理解它们。我想做的就是将一个字符串 "A string of characters" 转换为 GZIP Base64 格式。我该如何实现?
所谓 GZIP Base64 格式,是指先使用 GZIP 压缩字符串,然后将其转换为Base64格式。
Base64OutputStream
。这里是一个示例类:import java.util.zip.GZIPOutputStream;
import org.apache.commons.codec.binary.Base64OutputStream;
public class Test {
public static void main(String[] args) {
String text = "a string of characters";
try {
Base64OutputStream b64os = new Base64OutputStream(System.out);
GZIPOutputStream gzip = new GZIPOutputStream(b64os);
gzip.write(text.getBytes("UTF-8"));
gzip.close();
b64os.close();
} catch (Throwable t) {
t.printStackTrace();
}
}
}
这将输出:
H4sIAAAAAAAAAEtUKC4pysxLV8hPU0jOSCxKTC5JLSoGAOP+cfkWAAAA
echo 'H4sIAAAAAAAAAEtUKC4pysxLV8hPU0jOSCxKTC5JLSoGAOP+cfkWAAAA' | base64 -d | gunzip
base64 -D
而不是上述命令中的base64 -d
。a string of characters
Base64
- 自版本1.8起readAllBytes
- 自版本1.9起GZIPInputStream
和 GZIPOutputStream
- 自版本1.1起public static void main(String[] args) throws IOException {
byte[] original = "string".getBytes(StandardCharsets.UTF_8);
// encode
byte[] gzipToBase64 = encodeToBase64(encodeToGZIP(original));
System.out.println(new String(gzipToBase64));
//H4sIAAAAAAAAACsuKcrMSwcAqbK+ngYAAAA=
// decode
byte[] fromBase64Gzip = decodeFromGZIP(decodeFromBase64(gzipToBase64));
System.out.println(Arrays.equals(original, fromBase64Gzip)); //true
}
public static byte[] decodeFromBase64(byte[] arr) {
return Base64.getDecoder().decode(arr);
}
public static byte[] encodeToBase64(byte[] arr) {
return Base64.getEncoder().encode(arr);
}
public static byte[] decodeFromGZIP(byte[] arr) throws IOException {
ByteArrayInputStream bais = new ByteArrayInputStream(arr);
GZIPInputStream gzip = new GZIPInputStream(bais);
return gzip.readAllBytes();
}
public static byte[] encodeToGZIP(byte[] arr) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
GZIPOutputStream gzip = new GZIPOutputStream(baos);
gzip.write(arr);
gzip.finish();
return baos.toByteArray();
}
另请参阅:在Java中将编码作为Base64
这是 此答案 的变体,但没有过时的内容,并使用 Vavr Try
:
public static Try<String> compress(String input) {
return Try.of(() -> {
ByteArrayOutputStream rstBao = new ByteArrayOutputStream();
GZIPOutputStream zos = new GZIPOutputStream(rstBao);
zos.write(input.getBytes(StandardCharsets.UTF_8));
zos.close();
return Base64.encodeBase64String(rstBao.toByteArray());
});
public static Try<String> decompress(String input) {
return Try.of(() -> IOUtils.toString(new GZIPInputStream(
new ByteArrayInputStream(Base64.decodeBase64(input))),
StandardCharsets.UTF_8));
}
}
// unit test
@Test
public void testStringCompression() {
var data = "I finally rest. And watch the sun rise on a grateful universe. The hardest choices require the strongest wills.";
var cs = Utilities.compress(data);
assertThat(cs.isSuccess());
var us = Utilities.decompress(cs.get());
assertThat(us.isSuccess() && us.get().equals(data));
}