java - Web3j：从智能合约中获取最新事件

Question

我正在使用org.web3j (4.8.4)和Java 11。我在 Kovan 网络上部署了一个智能合约。我想订阅我调用后发出的所有新事件subscribe(...)。我对之前发出的事件不感兴趣。这是我当前的代码：

public void subscribeToEvents() throws Exception {
    String wssUrl = "wss://kovan.infura.io/ws/v3/TOKEN";
    String contractAddress = "0x123...";
    
    // initialize web socket service
    WebSocketService wss = new WebSocketService(wssUrl, false);
    try {
        wss.connect();
    } catch (Exception e) {
        System.out.println("Error while connecting to WSS service: " + e);
        throw e;
    }

    // build web3j client
    Web3j web3j = Web3j.build(wss);

    // create filter for contract events
    EthFilter filter = new EthFilter(DefaultBlockParameterName.EARLIEST, DefaultBlockParameterName.LATEST, contractAddress);

    // subscribe to events
    web3j.ethLogFlowable(filter).subscribe(event -> {
        System.out.println("Event received");
        System.out.println(event);
    }, error -> {
        System.out.println("Error: " + error);
    });
}

但是，当我运行此代码时，它还会打印几天前发生的旧事件。如何更改代码，使其仅在我调用后打印智能合约发出的新subscribe(...)事件？

标签： javaethereumsmartcontractsweb3-java

Answer 1

更换

EthFilter filter = new EthFilter(DefaultBlockParameterName.EARLIEST, DefaultBlockParameterName.LATEST, contractAddress);

和

EthFilter filter = new EthFilter(DefaultBlockParameterName.LATEST, DefaultBlockParameterName.LATEST, contractAddress);

为我完成了这项工作。