我的目标是:
AWS Java SDK不允许推送输出流。因此,我必须将step2的
outputstream
转换为inputstream
。为此,我决定使用PipedInputStream
。但是,我的代码只是挂在
writeTo(out);
步骤中。此代码在grails应用程序中。当代码挂起时,CPU消耗不高:import org.apache.commons.imaging.formats.jpeg.xmp.JpegXmpRewriter;
AmazonS3Client client = nfile.getS3Client() //get S3 client
S3Object object1 = client.getObject(
new GetObjectRequest("test-bucket", "myfile.jpg")) //get the object.
InputStream isNew1 = object1.getObjectContent(); //create input stream
ByteArrayOutputStream os = new ByteArrayOutputStream();
PipedInputStream inpipe = new PipedInputStream();
final PipedOutputStream out = new PipedOutputStream(inpipe);
try {
String xmpXml = "<x:xmpmeta>" +
"\n<Lifeshare>" +
"\n\t<Date>"+"some date"+"</Date>" +
"\n</Lifeshare>" +
"\n</x:xmpmeta>";/
JpegXmpRewriter rewriter = new JpegXmpRewriter();
rewriter.updateXmpXml(isNew1,os, xmpXml); //This is step2
try {
new Thread(new Runnable() {
public void run () {
try {
// write the original OutputStream to the PipedOutputStream
println "starting writeto"
os.writeTo(out);
println "ending writeto"
} catch (IOException e) {
// logging and exception handling should go here
}
}
}).start();
ObjectMetadata metadata = new ObjectMetadata();
metadata.setContentLength(1024); //just testing
client.putObject(new PutObjectRequest("test-bucket", "myfile_copy.jpg", inpipe, metadata));
os.writeTo(out);
os.close();
out.close();
} catch (IOException e) {
// logging and exception handling should go here
}
}
finally {
isNew1.close()
os.close()
out.close()
}
上面的代码仅打印
starting writeto
并挂起。它不打印ending writeto
更新
通过将
writeTo
放在单独的线程中,文件现在正在写入S3,但是,只写入了1024字节。文件不完整。我如何编写从outputstream到S3的所有内容? 最佳答案
当您执行os.writeTo(out)时,它将尝试刷新整个流以将其输出,并且由于还没有人从另一侧读取内容(即inpipe),因此内部缓冲区已满并且线程停止了。
在写入数据之前,必须先设置阅读器,并确保它在单独的线程中执行(请参阅PipedOutputStream上的javadoc)。