I am trying to send objects to different parts of the environment using base64 encoding, but I get an "Illegal base64 character b7" error.
The encoding code:
public static String serialize(Serializable object) throws IOException {
try (ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(SIZE);
ObjectOutputStream outputStream = new ObjectOutputStream(byteArrayOutputStream)) {
outputStream.writeObject(object);
return Base64.getEncoder().encodeToString(byteArrayOutputStream.toByteArray());
}
}
The decoding code:
public static Serializable deserialize(String base64String) throws ClassNotFoundException, IOException {
byte[] decoded = Base64.getDecoder().decode(base64String);
try (ObjectInputStream inputStream = new ObjectInputStream(new ByteArrayInputStream(decoded))) {
return (Serializable) inputStream.readObject();
}
}
I found the answer, it was in the code that decoded the object - it did not just receive encoded objects, but also regular objects x.x
After putting a check on that, my code worked.
Related
I want to write a class object to the string and then again create an object from it.
I searched on the net but all I found is to write an object to file however I want to write in the string, not on file.
Below is the example of writing to file similarly I want to write in String or similar Object and not in the file.
some_class implements serializable {
...
}
FileOutputStream f = new FileOutputStream(new File("myObjects.txt"));
ObjectOutputStream o = new ObjectOutputStream(f);
// Write objects to file
o.writeObject(object1);
o.close();
f.close();
FileInputStream fi = new FileInputStream(new File("myObjects.txt"));
ObjectInputStream oi = new ObjectInputStream(fi);
// Read objects
some_class object2 = (some_class) oi.readObject();
oi.close();
fi.close();
Please help with the same.
This would be one way:
try
{
// To String
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream os = new ObjectOutputStream(bos);
os.writeObject(object1);
String serializedObject1 = bos.toString();
os.close();
// To Object
ByteArrayInputStream bis = new ByteArrayInputStream(serializedObject1.getBytes());
ObjectInputStream oInputStream = new ObjectInputStream(bis);
YourObject restoredObject1 = (YourObject) oInputStream.readObject();
oInputStream.close();
} catch(Exception ex) {
ex.printStackTrace();
}
I would prefer the Base64 way though.
This would be an example of encoding:
private static String serializableToString( Serializable o ) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(o);
oos.close();
return Base64.getEncoder().encodeToString(baos.toByteArray());
}
And this is an example of decoding:
private static Object objectFromString(String s) throws IOException, ClassNotFoundException
{
byte [] data = Base64.getDecoder().decode(s);
ObjectInputStream ois = new ObjectInputStream(
new ByteArrayInputStream(data));
Object o = ois.readObject();
ois.close();
return o;
}
the best way to serialize an object to String and vice versa you should convert the object into JSON String and encode into base64. and to get object decode base64 and convert to object using GSON (opensource google provide java library)
class foo{ String name, email;
//setter getter
}
convert Object to base64 JSON
public static String convertToJson(Object o){
String result=new Gson().toJson(o);
return Base64.getEncoder().encodeToString(result);
}
//read base64
public static <T> T convertJsonToObject(String base64Object,Class<T> classOfT){
Gson gson = new Gson();
return gson.fromJson(new InputStreamReader(new ByteArrayInputStream(Base64.getDecoder().decode(base64Object))),classOfT);
}
public static void main(String[] args) {
foo obj=new foo("jhon","jhon#gamil.com");
String json=convertToJson(foo);
System.out.println(json);
foo obj_fromJson=convertJsonToObject(json,foo.class);
System.out.println(obj_fromJson.getName());
}
I'm trying to read and write objects into a file. Reading the output into a new object works, but every value is null.
Here's the code:
public void read() throws Exception
{
try
{
FileInputStream fIn = new FileInputStream(file);
ObjectInputStream in = new ObjectInputStream(fIn);
Object obj = in.readObject();
System.out.println(obj);
public void save() throws Exception
{
FileOutputStream fOut = new FileOutputStream(file.toString());
ObjectOutputStream out = new ObjectOutputStream(fOut);
out.writeObject(this);
out.flush();
out.close();
}
Here is the file output: (image of output)
I'd like to receive the values I previously wrote to the file in the new object created, however all I get is null for all values.
Edit: since people are asking for the entire class, and I have no idea what code could be causing what, here's the entire UserFile class: https://pastebin.com/Gr1tcGsg
I have ran that code and it works which means you most likely read before you write or you got an exception such as InvalidClassException: no valid constructor which would make sense in your case.
The code I ran:
public class SavedObject implements Serializable
{
public static void main(String[] args) throws IOException, ClassNotFoundException
{
new SavedObject();
}
private final int random;
private SavedObject() throws IOException, ClassNotFoundException
{
random = ThreadLocalRandom.current().nextInt();
File file = new File("Object.txt");
save(file);
read(file);
}
private void save(File file) throws IOException
{
FileOutputStream fileOutput = new FileOutputStream(file);
ObjectOutputStream objectOutput = new ObjectOutputStream(fileOutput);
objectOutput.writeObject(this);
objectOutput.close();
fileOutput.close();
System.out.println(this);
}
private void read(File file) throws IOException, ClassNotFoundException
{
FileInputStream fileInput = new FileInputStream(file);
ObjectInputStream objectInput = new ObjectInputStream(fileInput);
Object obj = objectInput.readObject();
System.out.println(obj);
objectInput.close();
fileInput.close();
}
public String toString()
{
return "SavedObject(Random: " + random + ")";
}
}
Which prints:
SavedObject(Random: -2145716528)
SavedObject(Random: -2145716528)
Also a few tips for you:
Don't have a try-catch if you throws
Have more readable variable names
Send more code in your next question
ObjectOutputStream is not recommended, if you can, you should write the values as they are
Don't use throws "Exception" instead use throws "
Put the file in instead of file.toString()
I found the problem, it was that in my constructor I wasn't correctly applying the retrieved info from the file. Thanks for everyone's help.
I have a problem that I have not been able to solve and it does not occur to me that it could be.
I have a class to which I am passing an InputStream from the main method, the problem is that when transforming the InputString to String with the class IOUtils.toString of AWS, or with the IOUtils of commons-io, they return
an empty String
No matter what the problem may be, since inside the main class, it works correctly and returns the String it should, but when I use it inside the other class (without having done anything), it returns the empty String to me.
these are my classes:
public class Main {
public static void main(String [] args) throws IOException {
InputStream inputStream = new ByteArrayInputStream("{\"name\":\"Camilo\",\"functionName\":\"hello\"}".getBytes());
OutputStream outputStream = new ByteArrayOutputStream();
LambdaExecutor lambdaExecutor = new LambdaExecutor();
String test = IOUtils.toString(inputStream); //this test variable have "{\"name\":\"Camilo\",\"functionName\":\"hello\"}"
lambdaExecutor.handleRequest(inputStream,outputStream);
}
}
and this:
public class LambdaExecutor{
private FrontController frontController;
public LambdaExecutor(){
this.frontController = new FrontController();
}
public void handleRequest(InputStream inputStream, OutputStream outputStream) throws IOException {
//Service service = frontController.findService(inputStream);
String test = IOUtils.toString(inputStream); //this test variable have "" <-empty String
System.exit(0);
//service.execute(inputStream, outputStream, context);
}
}
I used the debug tool, and the InputStream object is the same in both classes
By the time that you've passed the stream into handleRequest(), you've already consumed the stream:
public static void main(String [] args) throws IOException {
InputStream inputStream = new ByteArrayInputStream("{\"name\":\"Camilo\",\"functionName\":\"hello\"}".getBytes());
OutputStream outputStream = new ByteArrayOutputStream();
LambdaExecutor lambdaExecutor = new LambdaExecutor();
String test = IOUtils.toString(inputStream); //this consumes the stream, and nothing more can be read from it
lambdaExecutor.handleRequest(inputStream,outputStream);
}
When you took that out, the method worked as, as you said in the comments.
If you want the data to be re-useable, you'll have to use the reset() method if you want the same data again, or close and re-open the stream to re-use the object with different data.
// have your data
byte[] data = "{\"name\":\"Camilo\",\"functionName\":\"hello\"}".getBytes();
// open the stream
InputStream inputStream = new ByteArrayInputStream(data);
...
// do something with the inputStream, and reset if you need the same data again
if(inputStream.markSupported()) {
inputStream.reset();
} else {
inputStream.close();
inputStream = new ByteArrayInputStream(data);
}
...
// close the stream after use
inputStream.close();
Always close the stream after you use it, or use a try block to take advantage of AutoCloseable; you can do the same with the output stream:
try (InputStream inputStream = new ByteArrayInputStream(data);
OutputStream outputStream = new ByteArrayOutputStream()) {
lambdaExecutor.handleRequest(inputStream, outputStream);
} // auto-closed the streams
The reason you can't is because you can only read from a stream once.
To be able to read twice, you must call the reset() method for it to return to the beginning. After reading, call reset() and you can read it again!
Some sources don't support resetting it so you would actually have to create the stream again. To check if the source supports it, use the markSupported() method of the stream!
I have a file containing java objects, wrote with this code:
from(somewhere).process(new Processor() {
#Override
public void process(final Exchange exchange) {
...
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutput out = new ObjectOutputStream(bos);
out.writeObject(myObject);
exchange.getOut().setBody(bos.toByteArray());
}
}).to("file://pathFile");
And now, I want read them fastly. I don't know how can I do that, something like the following code I gess.
from("file://pathFile").convertBodyTo(String.class)
.split(body().tokenize("???")) // How can I tokenize my file ?
.streaming().threads(2)
.process(new Processor() {
#Override
public void process(final Exchange exchange) {
String filePath = (String) exchange.getIn().getHeader(Exchange.FILE_PATH);
File file = new File(filePath);
MyObject myObject = null;
try {
FileInputStream fis = new FileInputStream(file);
InputStream buffer = new BufferedInputStream(fis);
ObjectInput input = new ObjectInputStream(buffer);
Object obj = null;
while ((obj = input.readObject()) != null) {
// Do something
myObject = obj;
}
} catch (Exception e) {
...
} finally {
...
}
exchange.getIn().setBody(myObject);
}
}).to(somewhere);
EDIT: I edit my way to read object. There is still a problem with that code, we can't append to an ObjectOutputStream. That will corrupt the stream. There is a solution [here] for this problem. We can only write the stream header one time.
But If I do that, I wont be able to split and read my file with multiple threads. So can I split or access my file on ObjectOutputStream header ?
you just converted it to a String using convertBodyTo(String.class), therefore you have a String in the body rather than an InputStream....
I have a class which has a method that is receiving an object as a parameter.
This method is invoked via RMI.
public RMIClass extends Serializable {
public RMIMethod(MyFile file){
// do stuff
}
}
MyFile has a property called "body", which is a byte array.
public final class MyFile implements Serializable {
private byte[] body = new byte[0];
//....
public byte[] getBody() {
return body;
}
//....
}
This property holds the gzipped data of a file that was parsed by another application.
I need to decompress this byte array before performing further actions with it.
All the examples I see of decompressing gzipped data assume that I want to write it to the disk and create a physical file, which I do not.
How do I do this?
Thanks in advance.
Wrap your byte array with a ByteArrayInputStream and feed it into a GZipInputStream
Look at those samples, and wherever they're using FileOutputStream, use ByteArrayOutputStream instead. Wherever they're using FileInputStream, use ByteArrayInputStream instead. The rest should be simple.
JDK 9+
private byte[] gzipUncompress(byte[] compressedBytes) throws IOException {
try (InputStream inputStream = new GZIPInputStream(new ByteArrayInputStream(compressedBytes))) {
try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
inputStream.transferTo(outputStream);
return outputStream.toByteArray();
}
}
}
Why don't you create your own class that extends OutputStream or , whatever is the archive writing to ?
If you want to write to a ByteBuffer you can do this.
private static void uncompress(final byte[] input, final ByteBuffer output) throws IOException
{
final GZIPInputStream inputGzipStream = new GZIPInputStream(new ByteArrayInputStream(input));
Channels.newChannel(inputGzipStream).read(output);
}