前言
在solidity 0.4 时代，是不支持返回struct的。但现在solidity已经进入了0.8的版本，这个版本是支持直接返回struct与struct array的，以下为具体做法。
代码示例
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
contract ContractFactory {
struct User {
uint256 id;
uint256 age;
string name;
}
mapping(uint256 => User) public users;
mapping(uint256 => User[]) public userGroup;
function init() public {
User memory newUser1 = User({
id: 1,
age: 24,
name: "lily"
});
User memory newUser2 = User({
id: 2,
age: 25,
name: "brain"
});
userGroup[1].push(newUser1);
userGroup[1].push(newUser2);
User storage newUser = users[1];
newUser.age = 16;
newUser.name = "amber";
userGroup[1].push(newUser);
}
function getStruct() public view returns (User memory) {
User memory user = users[1];
return user;
}
function getStructArray() public view returns (User[] memory) {
User[] memory group = userGroup[1];
return group;
}
function getStructArrayLength() public view returns(uint256) {
return userGroup[1].length;
}
}
web3调用结果
getStruct() :: [ '0', '16', 'amber', id: '0', age: '16', name: 'amber' ]
getStructArray() :: [
[ '1', '24', 'lily', id: '1', age: '24', name: 'lily' ],
[ '2', '25', 'brain', id: '2', age: '25', name: 'brain' ],
[ '0', '16', 'amber', id: '0', age: '16', name: 'amber' ]
]
我们看到，是以数字形式呈现的，其中struct值以 值+键值对 呈现。
