Blockchain is a decentralized, distributed database that uses cryptography to store and secure data. It is a powerful and flexible platform that has the potential to transform a wide range of industries and applications.

If you’re new to programming and interested in developing blockchain applications, this tutorial will provide you with the tools and resources you need to get started. We’ll cover the basics of blockchain programming, introduce you to popular tools and libraries, and walk you through the process of building a simple blockchain application.

First, if you want to get more familiar with blockchain, I invite you to check the “Exploring the World of Blockchain: Concepts, Advantages, Applications, and Limitations” article.

区块链编程的工具

There are a few key tools you’ll need to get started with blockchain programming. Here are some of the most popular and useful options:

1. 区块链平台：The first step in developing a blockchain application is choosing a blockchain platform. There are many options available, including public blockchains like Bitcoin and Ethereum, and private blockchains like Hyperledger and Corda. Each platform has its own set of features and capabilities, so you’ll need to choose the one that best meets your needs.
2. Programming Language:大多数区块链平台都支持多种编程语言，例如JavaScript，Python和Solidity。您需要选择一种您喜欢或愿意学习的语言，以便开始在区块链上进行编程。
3. 综合开发环境（IDE）：An IDE is a software application that provides a range of tools for writing and debugging code, such as syntax highlighting, code completion, and error checking. Some popular IDEs for blockchain programming include Remix, Visual Studio Code, and PyCharm.

Getting Started with Blockchain Programming

设置工具后，您可以开始学习区块链编程的基础知识。这是一些要理解的关键概念：

1. 智能合约：A smart contract is a self-executing contract with the terms of the agreement between buyer and seller being directly written into lines of code. The code and the agreements contained therein are deployed onto the blockchain.
2. 坚固：Solidity是一种专门设计用于以太坊平台上智能合约的编程语言。它类似于JavaScript，但具有一些语法差异和其他功能。
3. Web3.js:Web3.js是一个库，可让您与Web浏览器与以太坊区块链进行交互。它使您可以发送交易，部署合同并从区块链中读取数据。您可以使用任何可以提出HTTP请求的编程语言的Web3.js，例如JavaScript，Python或Ruby。
4. Truffle:松露是以太坊的开发框架，它为建造，测试和部署智能合约提供了一组工具和库。它包括一套测试工具，用于与区块链互动的控制台以及预先构建的合同模板库。

区块链应用的示例

以下是区块链应用程序的一些示例，可帮助您了解可以构建的项目类型：

1. Decentralized marketplace:A decentralized marketplace is an online platform that allows buyers and sellers to trade goods and services directly, without the need for a central authority or intermediary. A blockchain-based marketplace could use smart contracts to automate the process of buying and selling, and to ensure the security and transparency of transactions.
2. 供应链管理：A blockchain-based supply chain management system could track the movement of goods and materials through the supply chain, from source to consumer. It could use smart contracts to automate the process of ordering, shipping, and payment, and to provide real-time visibility into the status of orders.
3. Identity management:A blockchain-based identity management system could use smart contracts to store and verify identity information, such as passports and birth certificates. It could enable individuals to prove their identity and access services, and reduce the risk of identity theft and fraud.

样本区块链应用：

现在，您对区块链编程和应用程序的一些示例有了基本的了解，让我们介绍构建简单的区块链应用程序的过程。我们将创建一个简单的“ Hello World”智能合约，在区块链上显示消息。

1.Set up your project:创建一个新的项目文件夹，并通过在终端中运行“松露init”来初始化松露项目。这将为您的项目创建一个基本的文件夹结构和配置文件。

2.创建智能合约：Create a new file called “HelloWorld.sol” in the “contracts” folder, and write the following code:

pragma solidity ^0.6.0;

合同helloworld {
字符串公共消息；

constructor（）public {
消息=“你好，世界！”;
}
}

This is a basic Solidity contract that defines a string variable called “message” and sets its value to “Hello, world!” in the constructor function.

3. Compile the contract: Run “truffle compile在终端中汇编合同。这将生成带有编译合同数据的JSON文件。

4. Deploy the contract: Run “松露迁移在终端中，将合同部署到区块链。这将在区块链上创建一个新的合同实例，并为其分配一个唯一的地址。

5.与合同互动：您可以使用松露的控制台与合同进行交互并读取“消息”变量的值。跑步 ”truffle console” in the terminal, and then enter the following commands:

let contract = await HelloWorld.deployed()
let message = await contract.message()

这将检索合同实例和“消息”变量的值，并将其显示在控制台中。然后，您可以使用这些值与合同进行交互并从区块链中检索数据。

6. Test the contract: You can use Truffle’s testing framework to write and run tests for your contract. Create a new file called “HelloWorld.test.js” in the “test” folder, and write the following code:

const HelloWorld = artifacts.require("HelloWorld");

contract("HelloWorld", () => {
it(
“应该显示正确的消息”，
async () => {
const Contract =等待Helloworld.Deployed（）;
const message =等待合同。
assert.equal（消息，“你好，世界！”，“显示不正确的消息”）;
}
);
});

这是一个简单的测试，可检索合同实例和“消息”变量的价值，并验证其等于“ Hello，World！”。

7.运行测试：运行“truffle test” in the terminal to run the test. If the test passes, you will see a message indicating that the contract is working as expected.

In this tutorial, we covered the basics of blockchain programming and introduced you to some popular tools and libraries for building blockchain applications. We also walked through the process of building a simple blockchain application, and showed you how to write and run tests for your contract. With the knowledge and skills you’ve learned, you are now ready to start building your own blockchain applications. Remember to continue practicing and learning, and to explore the many resources and communities available to help you on your journey as a blockchain developer.

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Looking for a more advanced tutorial with full code? I invite you then to check my next article “构建区块链健康应用程序：带完整代码的分步指南”。