使用输入/输出流的Java LZ4压缩
我正在使用jpountzlz4来尝试压缩文件,我想使用Java文件输入和输出流来读取和输出文件。我试着在网上找到一个解决方案,但什么都没有,我发现了一个关于如何正确实现LZ4的stackoverflow问题,我已经解决了这个问题,并试图修改它以使用流,但我不确定这是否正确,或者它是否起作用 在文本文件上运行压缩时,它会输出缺少某些字符或替换为符号的文件使用输入/输出流的Java LZ4压缩,java,lz4,Java,Lz4,我正在使用jpountzlz4来尝试压缩文件,我想使用Java文件输入和输出流来读取和输出文件。我试着在网上找到一个解决方案,但什么都没有,我发现了一个关于如何正确实现LZ4的stackoverflow问题,我已经解决了这个问题,并试图修改它以使用流,但我不确定这是否正确,或者它是否起作用 在文本文件上运行压缩时,它会输出缺少某些字符或替换为符号的文件 ðHello world Heðo world Hello ðrld Hello worlðHello worl 但是当使用图像文件运行它时,
ðHello world Heðo world Hello ðrld Hello worlðHello worl
但是当使用图像文件运行它时,会抛出一个越界错误。我也无法让解压工作,因为它会抛出一个错误,解码输入缓冲区的偏移量3
这是我的代码任何帮助都会很感激谢谢
public void LZ4Compress(InputStream in, OutputStream out){
int noBytesRead = 0; //number of bytes read from input
int noBytesProcessed = 0; //number of bytes processed
try {
while ((noBytesRead = in.read(inputBuffer)) >= 0) {
noBytesProcessed = inputBuffer.length;
decompressedLength = inputBuffer.length;
outputBuffer = compress(inputBuffer, decompressedLength);
out.write(outputBuffer, 0, noBytesRead);
}
out.flush();
in.close();
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void LZ4decompress(InputStream in, OutputStream out){
int noBytesRead = 0; //number of bytes read from input
try {
while((noBytesRead = in.read(inputBuffer)) >= 0){
noBytesProcessed = inputBuffer.length;
outputBuffer = decompress(inputBuffer);
out.write(outputBuffer, 0, noBytesRead);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static byte[] compress(byte[] src, int srcLen) {
decompressedLength = srcLen;
int maxCompressedLength = compressor.maxCompressedLength(decompressedLength);
byte[] compressed = new byte[maxCompressedLength];
int compressLen = compressor.compress(src, 0, decompressedLength, compressed, 0, maxCompressedLength);
byte[] finalCompressedArray = Arrays.copyOf(compressed, compressLen);
return finalCompressedArray;
}
private static LZ4SafeDecompressor decompressor = factory.safeDecompressor();
public static byte[] decompress(byte[] finalCompressedArray) {
byte[] restored = new byte[finalCompressedArray.length];
restored = decompressor.decompress(finalCompressedArray, finalCompressedArray.length);
return restored;
}
只看代码,我会说您在这里出了问题:
outputBuffer = compress(inputBuffer, decompressedLength);
out.write(outputBuffer, 0, noBytesRead);
您已经在compress中修剪了outputBuffer。尝试:
out.write(outputBuffer);
因此,我使用LZ4block输入/输出流解决了我的问题
public static void LZ4compress(String filename, String lz4file){
byte[] buf = new byte[2048];
try {
String outFilename = lz4file;
LZ4BlockOutputStream out = new LZ4BlockOutputStream(new FileOutputStream(outFilename), 32*1024*1024);
FileInputStream in = new FileInputStream(filename);
int len;
while((len = in.read(buf)) > 0){
out.write(buf, 0, len);
}
in.close();
out.close();
} catch (IOException e) {
}
}
public static void LZ4Uncompress(String lz4file, String filename){
byte[] buf = new byte[2048];
try {
String outFilename = filename;
LZ4BlockInputStream in = new LZ4BlockInputStream(new FileInputStream(lz4file));
FileOutputStream out = new FileOutputStream(outFilename);
int len;
while((len = in.read(buf)) > 0){
out.write(buf, 0, len);
}
in.close();
out.close();
} catch (IOException e) {
}
}
这修复了我的越界错误,它似乎适用于所有文件类型,问题是输出文件比原始文件大。很可能压缩是以小块的形式结束的,这比一次压缩整个文件的效果要差。@user3758298-我有一个问题,比如如果我不知道解压缩数组的长度,那么我应该如何解压缩字节数组?我有一个压缩字节数组。我想把它解压缩。