无法使用Java压缩多个文件

Question

Getting data onto inputStream object from web url

inputStream = AWSFileUtil.getInputStream(
                    AWSConnectionUtil.getS3Object(null),
                    "cdn.generalsentiment.com", filePath);

If they are mutliple files then i want to zip them and sent the filetype as "zip" to struts.xml which does the download.

actually am converting the inputstream into byteArrayInputStream

ByteArrayInputStream byteArrayInputStream = new    
ByteArrayInputStream(inputStream.toString().getBytes());
            while (byteArrayInputStream.read(inputStream.toString().getBytes()) > 0) {
                zipOutputStream.write(inputStream.toString().getBytes());
            }

and then

 zipOutputStream.close();
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        fileInputStream = new FileInputStream(file);
        while (fileInputStream.read(buffer) > 0) {
            byteArrayOutputStream.write(buffer);
        }
        byteArrayOutputStream.close();
        inputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
        reportName = "GS_MediaValue_Reports.zip";
        fileType = "zip";
    } 

    return fileType;

But the downloaded zip when extracted gives corrupt files. Please suggest me a solution for this issue.

Answer 1

The short answer is that it's not how ZipOutputStream works. Since it was designed to store multiple files, along with their file names, directory structures and so on, you need to tell the stream about that explicitly.

Furthermore, converting a stream to a string is a bad idea in general, plus it's slow, especially when you're doing it in a loop.

So your solution will be something like:

ZipEntry entry = new ZipEntry( fileName ); // You have to give each entry a different filename
zipOutputStream.putNextEntry( entry );
byte buffer[] = new byte[ 1024 ]; // 1024 is the buffer size here, but it could be anything really
int count;
while( (count = inputStream.read( buffer, 0, 1024 ) ) != -1 ) {
    zipOutputStream.write( buffer, 0, count );
}