簡單呼叫部署在鏈上的合約

• 部署的合約：Multicall.sol

/**
 *Submitted for verification at Etherscan.io on 2019-06-10
*/

pragma solidity >=0.5.0;
pragma experimental ABIEncoderV2;
// SPDX-License-Identifier: GPL-3.0

/// @title Multicall - Aggregate results from multiple read-only function calls
/// @author Michael Elliot <mike@makerdao.com>
/// @author Joshua Levine <joshua@makerdao.com>
/// @author Nick Johnson <arachnid@notdot.net>

contract Multicall {
    struct Call {
        address target;
        bytes callData;
    }
    function aggregate(Call[] memory calls) public returns (uint256 blockNumber, bytes[] memory returnData) {
        blockNumber = block.number;
        returnData = new bytes[](calls.length);
        for(uint256 i = 0; i < calls.length; i++) {
            (bool success, bytes memory ret) = calls[i].target.call(calls[i].callData);
            require(success);
            returnData[i] = ret;
        }
    }
    // Helper functions
    function getEthBalance(address addr) public view returns (uint256 balance) {
        balance = addr.balance;
    }
    function getBlockHash(uint256 blockNumber) public view returns (bytes32 blockHash) {
        blockHash = blockhash(blockNumber);
    }
    function getLastBlockHash() public view returns (bytes32 blockHash) {
        blockHash = blockhash(block.number - 1);
    }
    function getCurrentBlockTimestamp() public view returns (uint256 timestamp) {
        timestamp = block.timestamp;
    }
    function getCurrentBlockDifficulty() public view returns (uint256 difficulty) {
        difficulty = block.difficulty;
    }
    function getCurrentBlockGasLimit() public view returns (uint256 gaslimit) {
        gaslimit = block.gaslimit;
    }
    function getCurrentBlockCoinbase() public view returns (address coinbase) {
        coinbase = block.coinbase;
    }
}

• js呼叫合約

//引入web3
const Web3 = require('web3');
const web3 = new Web3('http://192.168.75.129:8545');

//部署合約的abi
const abi = [
    {
        "constant": false,
        "inputs": [
            {
                "components": [
                    {
                        "internalType": "address",
                        "name": "target",
                        "type": "address"
                    },
                    {
                        "internalType": "bytes",
                        "name": "callData",
                        "type": "bytes"
                    }
                ],
                "internalType": "struct Multicall.Call[]",
                "name": "calls",
                "type": "tuple[]"
            }
        ],
        "name": "aggregate",
        "outputs": [
            {
                "internalType": "uint256",
                "name": "blockNumber",
                "type": "uint256"
            },
            {
                "internalType": "bytes[]",
                "name": "returnData",
                "type": "bytes[]"
            }
        ],
        "payable": false,
        "stateMutability": "nonpayable",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [
            {
                "internalType": "uint256",
                "name": "blockNumber",
                "type": "uint256"
            }
        ],
        "name": "getBlockHash",
        "outputs": [
            {
                "internalType": "bytes32",
                "name": "blockHash",
                "type": "bytes32"
            }
        ],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [],
        "name": "getCurrentBlockCoinbase",
        "outputs": [
            {
                "internalType": "address",
                "name": "coinbase",
                "type": "address"
            }
        ],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [],
        "name": "getCurrentBlockDifficulty",
        "outputs": [
            {
                "internalType": "uint256",
                "name": "difficulty",
                "type": "uint256"
            }
        ],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [],
        "name": "getCurrentBlockGasLimit",
        "outputs": [
            {
                "internalType": "uint256",
                "name": "gaslimit",
                "type": "uint256"
            }
        ],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [],
        "name": "getCurrentBlockTimestamp",
        "outputs": [
            {
                "internalType": "uint256",
                "name": "timestamp",
                "type": "uint256"
            }
        ],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [
            {
                "internalType": "address",
                "name": "addr",
                "type": "address"
            }
        ],
        "name": "getEthBalance",
        "outputs": [
            {
                "internalType": "uint256",
                "name": "balance",
                "type": "uint256"
            }
        ],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [],
        "name": "getLastBlockHash",
        "outputs": [
            {
                "internalType": "bytes32",
                "name": "blockHash",
                "type": "bytes32"
            }
        ],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    }
];
//部署到鏈上的合約的地址
const address = '0xd573A1f062751A4f947f1769B5D78c1815420bf9';
//通過new web3.eth.Contract(abi, address)動態創建一個合約實體
let MyContract = new web3.eth.Contract(abi, address);
//getEthBalance方法是合約中的方法，methods為調取合約方法的內置方法
MyContract.methods.getEthBalance('0x88ded3010c9e9b2b2d1914b07c0d674281952d19').call().then(console.log);