dapp-developmentethereumj
I am familiar creating Dapps by using Web3.js , I could able to do so , even in a normal browser ( without Mist). But wondering if that is possible by using EthereumJ ?
So instead of browser ( web3.js) connecting directing to the network and getting it done, the request should go through our hosted server which serves the data by using EhtereumJ ?
My Intention to use spring mvc web application.
The answer is you don't. Now I know you probably don't want to hear this but the HTTP JSON RPC was never meant to be used in such a way that it should be accessible from the outside. The RPC was brought in to existence so that you may develop against your own local node using your own browser.
What I suggest you do is that you setup a proxy that will proxy all requests to the locally running ethereum node instead of letting everyone directly interface with the ethereum node itself. This will give you controlled access and HTTPS.
Firstly you will need the following Maven pom.xml dependency:
<dependency>
<groupId>org.ethereum</groupId>
<artifactId>ethereumj-core</artifactId>
<version>1.2.0-RELEASE</version>
<!-- <type>zip</type> -->
</dependency>
And here is the code to create a private key / account pair:
import org.ethereum.crypto.ECKey;
import org.spongycastle.util.encoders.Hex;
public class CreateAccount {
public static void main(String[] args) {
ECKey key = new ECKey();
byte[] addr = key.getAddress();
byte[] priv = key.getPrivKeyBytes();
String addrBase16 = Hex.toHexString(addr);
String privBase16 = Hex.toHexString(priv);
System.out.println("Address : " + addrBase16);
System.out.println("Private Key : " + privBase16);
}
}
Running the code twice produces the following output:
Address : 82d4b1c01afaf7f25bb21fd0b4b4c4a7eb7120ce
Private Key : 133965f412d1362645cbd963619023585abc8765c7372ed238374acb884b2b3a
Address : 68ccabefc7f4ae21ce0df1d98e50e099d7fc290f
Private Key : 1caeb7f26cb9f3cc7d9d0dbcdd3cf3cb056dbc011ec9013e8f3b8cdb2f193b32
Verifying the information with https://www.myetherwallet.com/#view-wallet-info:
And note that the accounts created in EthereumJ are all lowercase while the accounts generated from the private keys using MyEtherWallet are mixed case. This is because MyEtherWallet is using the new checksummed accounts. See Yet another cool checksum address encoding #55.
Best Answer
You could probably do this, but it's unlikely to be the best approach.
All three main clients expose a set of APIs via JSON-RPC; this is what web3 apps call. Instead of integrating directly with a client, you should run a stock node, and call these APIs from your webapp.