CODEWITHSUNDEEP
javanetty
zettel
zettel

Reputation: 13

Read and Write strings via ByteBuf using byte[] array

I'm trying to send a string through netty with a ByteBuf. First of all I convert the string to a byte array like that:

byteBuf.writeInt(this.serverName.length());
byteBuf.writeInt(this.ipAdress.length());

byteBuf.writeBytes(this.serverName.getBytes(StandardCharsets.UTF_8));
byteBuf.writeBytes(this.ipAdress.getBytes(StandardCharsets.UTF_8));

This works well, but I don't know how to read the bytes to convert them back to the string?

I tried something like that:

int snLen = byteBuf.readInt();
int ipLen = byteBuf.readInt();

byte[] bytes = new byte[byteBuf.readableBytes()];

System.out.println(byteBuf.readBytes(bytes).readByte());
this.ipAdress = "";

There must be something to get the bytes back. You can send bytes from a string but can't get the bytes back at the end? Seems like there is a method for that, but I don't have an idea how to do that.

I hope anyone from you can help me. Thanks in advance! :)

Upvotes: 1

Views: 5332

Answers (3)

Wayne
Wayne

Reputation: 3519

Here is an untested answer:

I assume the data order is correct.

Use this, method "readBytes(ByteBuf dst, int length)" : readBytes

Transmit side change to:

byteBuf.writeInt(this.serverName.getBytes().length);
byteBuf.writeInt(this.ipAdress.getBytes().length);

Receiving side:

int snLen = byteBuf.readInt();
int ipLen = byteBuf.readInt();

byte[] bytesServerName = new byte[snLen];
byte[] bytesIp = new byte[ipLen];

byteBuf.readBytes(bytesServerName,snLen);
byteBuf.readBytes(bytesIp, ipLen);

String serverName  = new String(bytesServerName); 
String ipAddress   = new String(bytesIp);   

System.out.println(bytesServerName);
System.out.println(bytesIp);

Upvotes: 1

Nicholas
Nicholas

Reputation: 16056

How about using Netty's own StringEncoder and StringDecoder ? http://netty.io/4.1/api/io/netty/handler/codec/string/StringEncoder.html

Upvotes: 1

Norman Maurer
Norman Maurer

Reputation: 23557

In netty 4.1 you can use:

byteBuf.writeCharSequence(...)
byteBuf.readCharSequence(...)

Upvotes: 2

Related Questions