Getting started with Amazon S3 sdk with java

Put the sdk in your pom.xml of your maven project:

1. <dependency>
2.     <groupId>com.amazonaws</groupId>
3.     <artifactId>aws-java-sdk</artifactId>
4.     <version>1.9.13</version>
5. </dependency>

Check out the simplest sample code https://github.com/aws/aws-sdk-java/blob/master/src/samples/AmazonS3/S3Sample.java

Before running, make sure you setup API credentials properly.Follow the instruction here to do this :

http://mohiplanet.blogspot.com/2014/12/setting-up-aws-s3-api-java-client.html

Creating a directory:-

http://voidweb.com/2013/03/how-to-create-a-folder-programmatically-in-s3-using-amazon-aws-java-sdk/ has good examples for creating a directory

Uploading a file:-
Here is an for uploading a file which will be publicly accessible:
http://mohiplanet.blogspot.com/2014/11/aws-s3-multipart-file-upload-with.html
About content type:-
Note:- You have to select appropriate content types for each of your files. S3 SDK is not gonna do it automatically  for you.
Here is a sample that you can use during uploading with correct content type:-

1. public ObjectMetadata generateCorrectContentTypeObjMetaFromKeyName(String key) throws InvalidContentTypeException {
2. ObjectMetadata metadata = new ObjectMetadata();
3. String contentType = getFileContentTypeFromFileName(key);
4. if (contentType.length() == 0) {
5. throw new InvalidContentTypeException();
6. }
7. LOG.log(Level.INFO, "Setting content type : " + contentType);
8. metadata.setContentType(contentType);
9. return metadata;
10. }

Set content type according to your key name with:

1. initRequest.setObjectMetadata(generateCorrectContentTypeObjMetaFromKeyName(keyName));

 Details and definition of getFileContentTypeFromFileName(key) are here:-
 http://mohiplanet.blogspot.com/2014/12/amazon-web-services-s3-api-java-client.html

More examples:-
https://github.com/aws/aws-sdk-java/tree/master/src/samples/AmazonS3

Command line tools for working fast:-
http://s3tools.org/s3cmd