We Keep Coding

AWS Creating new files from an s3 object using JAVA getting error

I have a shape file and i need to read the shape file from my java code. I used below code for reading shape file.
public class App {
public static void main(String[] args) {
File file = new File("C:\\Test\\sample.shp");
Map<String, Object> map = new HashMap<>();//
try {
map.put("url", URLs.fileToUrl(file));
DataStore dataStore = DataStoreFinder.getDataStore(map);
String typeName = dataStore.getTypeNames()[0];
SimpleFeatureSource source = dataStore.getFeatureSource(typeName);
SimpleFeatureCollection collection = source.getFeatures();
try (FeatureIterator<SimpleFeature> features = collection.features()) {
while (features.hasNext()) {
SimpleFeature feature = features.next();
SimpleFeatureType schema = feature.getFeatureType();
Class<?> geomType = schema.getGeometryDescriptor().getType().getBinding();
String type = "";
if (Polygon.class.isAssignableFrom(geomType) || MultiPolygon.class.isAssignableFrom(geomType)) {
MultiPolygon geom = (MultiPolygon) feature.getDefaultGeometry();
type = "Polygon";
if (geom.getNumGeometries() > 1) {
type = "MultiPolygon";
}
} else if (LineString.class.isAssignableFrom(geomType)
|| MultiLineString.class.isAssignableFrom(geomType)) {
} else {
}
System.out.println(feature.getDefaultGeometryProperty().getValue().toString());
}
}
} catch (Exception e) {
// TODO: handle exception
}
}
}
I got the desired output. But my requirement is write an aws lambda function to read shape file. For this
1. I created a Lambda java project of s3 event. I wrote the same code inside the handleRequest. I uploaded the java lambda project as a lanbda function and added one trigger. When I am uploading a .shp file to as s3 bucket lmbda function will automatically invoked. But I am getting an error like below
java.lang.RuntimeException: java.io.FileNotFoundException: /sample.shp (No such file or directory)
I have sample.shp file inside my s3 bucket. I go through below link.
How to write an S3 object to a file?
I am getting the same error. I tried to change my code like below
S3Object object = s3.getObject(new GetObjectRequest(bucket, key));
InputStream objectData = object.getObjectContent();
map.put("url", objectData );
instead of
File file = new File("C:\\Test\\sample.shp");
map.put("url", URLs.fileToUrl(file));
:-( Now i am getting an error like below
java.lang.NullPointerException
Also I tried the below code
DataStore dataStore = DataStoreFinder.getDataStore(objectData);
instead of
DataStore dataStore = DataStoreFinder.getDataStore(map);
the error was like below
java.lang.ClassCastException:
com.amazonaws.services.s3.model.S3ObjectInputStream cannot be cast to
java.util.Map
Also I tried to add key directly to the map and also as DataStore object. Everything went wrong..:-(
Is there anyone who can help me?
It will be very helpful if someone can do it for me...

The DataStoreFinder.getDataStore method in geotools requires you to provide a map containing a key/value pair with key "url". The value associated with that "url" key needs to be a file URL like "file://host/path/my.shp".
You're trying to insert a Java input stream into the map. That won't work, because it's not a file URL.
The geotools library does not accept http/https URLs (see the geotools code here and here), so you need a file:// URL. That means you will need to download the file from S3 to the local Lambda filesystem and then provide a file:// URL pointing to that local file. To do that, here's Java code that should work:
// get the shape file from S3 to local filesystem
File localshp = new File("/tmp/download.shp");
s3.getObject(new GetObjectRequest(bucket, key), localshp);
// now store file:// URL in the map
map.put("url", localshp.getURI().getURL().toString());
If the geotools library had accepted real URLs (not just file:// URLs) then you could have avoided the download and simply created a time-limited, pre-signed URL for the S3 object and put that URL into the map.
Here's an example of how to do that:
// get current time and add one hour
java.util.Date expiration = new java.util.Date();
long msec = expiration.getTime();
msec += 1000 * 60 * 60;
expiration.setTime(msec);
// request pre-signed URL that will allow bearer to GET the object
GeneratePresignedUrlRequest gpur = new GeneratePresignedUrlRequest(bucket, key);
gpur.setMethod(HttpMethod.GET);
gpur.setExpiration(expiration);
// get URL that will expire in one hour
URL url = s3.generatePresignedUrl(gpur);

Unable to convert bytes from charset 65535 in to Japanese (5035)

I have a character set conversion issue:
I am updating Japanese Kanji characters in DB2 in iSeries system with the following conversion method:
AS400 sys = new AS400("<host>","username","password");
CharConverter charConv = new CharConverter(5035, sys);
byte[] b = charConv.stringToByteArray(5035, sys, "試験");
AS400Text textConverter = new AS400Text(b.length, 65535,sys);
While retrieving, I use the following code to convert & display:
CharConverter charConv = new CharConverter(5035, sys);
byte[] bytes = charConv.stringToByteArray(5035, sys, dbRemarks);
String s = new String(bytes);
System.out.println("Remarks after conversion to AS400Text :"+s);
But, the system is displaying garbled characters while displaying. Can anybody help me to decode Japanese characters from binary storage?

Well I don't know anything about CharConverter or AS400Text, but code like this is almost always a mistake:
String s = new String(bytes);
That uses the platform default encoding to convert the binary data to text.
Usually storage and retrieval should go through opposite processes - so while you've started with a string and then converted it to bytes, and converted that to an AS400Text object when storing it, I'd expect you to start with an AS400Text object, convert that to a byte array, and then convert that to a String using CharConverter when fetching. The fact that you're calling stringToByteArray in both cases suggests there's something amiss.
(It would also help if you'd tell us what dbRemarks is, and how you've fetched it.)
I do note that having checked some documentation for AS400Text, I've seen this:
Due to recent changes in the behavior of the character conversion routines, this system object is no longer necessary, except when the AS400Text object is to be passed as a parameter on a Toolbox Proxy connection.
There's similar documentation for CharConverter. Are you sure you actually need to go through this at all? Have you tried just storing the string directly and retrieving it directly, without going through intermediate steps?

Thank you Jon Skeet!
Yes. I have committed a mistake, not encoding the string while declaration.
My issue is to get the data stored in DB2, convert it into Japanese and provide for editing in web page. I am getting dbRemarks from the result set. I have missed another thing in my post:
While inserting, I am converting to text like:
String text = (String) textConverter.toObject(b);
PreparedStatement prepareStatementUpdate = connection.prepareStatement(updateSql);
prepareStatementUpdate.setString(1, text);
int count = prepareStatementUpdate.executeUpdate();
I am able to retrieve and display clearly with this code:
String selectSQL = "SELECT remarks FROM empTable WHERE emp_id = ? AND dep_id=? AND join_date='2013-11-15' ";
prepareStatement = connection.prepareStatement(selectSQL);
prepareStatement.setInt(1, 1);
prepareStatement.setString(2, 1);
ResultSet resultSet = prepareStatement.executeQuery();
while ( resultSet.next() ) {
byte[] bytedata = resultSet.getBytes( "remarks" );
AS400Text textConverter2 = new AS400Text(bytedata.length, 5035,sys);
String javaText = (String) textConverter2.toObject(bytedata);
System.out.println("Remarks after conversion to AS400Text :"+javaText);
}
It is working fine with JDBC, but for working with JPA, I need to convert to string for editing in web page or store in table. So, I have tried this way, but could not succeed:
String remarks = resultSet.getString( "remarks" );
byte[] bytedata = remarks.getBytes();
AS400Text textConverter2 = new AS400Text(bytedata.length, 5035,sys);
String javaText = (String) textConverter2.toObject(bytedata);
System.out.println("Remarks after conversion to AS400Text :"+javaText);

Thanks a lot Jon and Buck Calabro !
With your clues, I have succeeded with the following approach:
String remarks = new String(resultSet.getBytes("remarks"),"SJIS");
byte[] byteData = remarks.getBytes("SJIS");
CharConverter charConv = new CharConverter(5035, sys);
String convertedStr = charConv.byteArrayToString(5035, sys, byteData);
I am able to convert from string. I am planning to implement the same with JPA, and started coding.

How to represent an image from database in JSON

I need to create JSON based on a blob from database. To get the blob image, I use the code below and after show in json array:
Statement s = connection.createStatement();
ResultSet r = s.executeQuery("select image from images");
while (r.next()) {
JSONObject obj = new JSONObject();
obj.put("img", r.getBlob("image"));
}
I to want return a JSON object for the each image according the image blob. How can I achieve it?

Binary data in JSON is usually best to be represented in a Base64-encoded form. You could use the standard Java SE provided DatatypeConverter#printBase64Binary() method to Base64-encode a byte array.
byte[] imageBytes = resultSet.getBytes("image");
String imageBase64 = DatatypeConverter.printBase64Binary(imageBytes);
obj.put("img", imageBase64);
The other side has just to Base64-decode it. E.g. in Android, you could use the builtin android.util.Base64 API for this.
byte[] imageBytes = Base64.decode(imageBase64, Base64.DEFAULT);

How do I make my program find the record store?

I've just started out with J2ME and record stores. This seems to be the proper way to open a record store named "foo", not creating a new one:
RecordStore.openRecordStore("foo", false)
Fine, I get that. But where do I put the actual file for my program to find it? I'm using NetBeans 7.1.2.

you don't need to know where the file is, J2Me put the file somewhere, if the store already exists, you can open it, or use true in the open method to create it if it doesn't exist.
RecordStore rs = RecordStore.openRecordStore("foo", true);
to write to your recordstore, use this :
String s = "your-data";
byte[] rec = s.getBytes();
rs.addRecord(rec, 0, rec.length);
to read :
RecordEnumeration re = rs.enumerateRecords(null, null, false);
while (re.hasNextElement()){
String s = new String(re.nextRecord());
}
and close your recordStore after each operation:
rs.closeRecordStore();
update
how do I read the contents of the file?
read your existing file as a normal file with :
InputStream is = getClass().getResourceAsStream("/res/foo");
StringBuffer sb = new StringBuffer();
int chars;
while ((chars = is.read()) != -1)
sb.append((char) chars);
String str = new String(String.valueOf(sb).getBytes("UTF-8"));
and write the string to your recordStore with the code above.

Delphi to Java code conversion

how can i convert the specific code written in Delphi to JAVA
try
LLine := TMemoryStream.Create;
IdTCPClient1.IOHandler.WriteLn('atext');
IdTCPClient1.IOHandler.ReadStream(LLine, -1);
LLine.Position := 0;
LLine.Read(intval, 4); //the server is sending memstream as integer + ajpeg image
Image1.Picture.Graphic.LoadFromStream(LLine);
finally
//free
end;
the above code works perfectly with Delphi , but now i want to create a java client too , but my own conversion is giving me error(java)
Image image = null ;
Socket socket = new Socket(someIP, myport);
My conversion is
InputStream in = socket.getInputStream();
OutputStream out = socket.getOutputStream();
String string = "atext\n";
byte buffer[] = string.getBytes();
out.write(buffer);
in.skip(4); // i don't want the integer
image = ImageIO.read(in);
the server is getting the text atext perfectly , but my java client is having a problem always image is showing a null value (i assigned a breakpoint and checked it );

The ImageIO.read(InputStream input) documentation says:
If no registered ImageReader claims to be able to read the resulting
stream, null is returned.
So the null value seems to be normal in this case. Have you checked that a matching ImageReader is registered? (For example by loading an existing, valid reference image file)