java区块链项目描述怎么写,java 区块链项目实战

本文将介绍Java区块链项目实战拓展的三个关键词：区块链、智能合约、以太坊。

区块链是一种分布式账本技术，它使用密码学算法来确保数据的安全性、不可篡改性和可追溯性。它是一个去中心化的数据存储和交换技术，可以用来记录交易、资产等信息。区块链的核心特性是去中心化，它的记录是由网络中的节点共同维护，这意味着数据不受任何机构或者个人的控制，也不存在安全风险。

智能合约是指通过区块链技术实现的一种可执行的自动化协议。它是一种可以自动执行、自动确认、自动执行的协议，可以在区块链网络中安全地存储和执行。智能合约可以实现自动执行，可以有效地管理合同，可以更有效地实现货币交易，并且可以更有效地确保合同的完整性。

以太坊是一个开放源代码的公共区块链平台，它支持智能合约和去中心化的应用程序（DAPP）。以太坊的核心特性是以太坊虚拟机（EVM），它是一个可编程的计算机，可以在以太坊网络上运行智能合约。以太坊的主要优势在于它提供了一个可编程的环境，可以用来创建和部署智能合约，以及执行去中心化的应用程序。

总之，Java区块链项目实战拓展的三个关键词：区块链、智能合约、以太坊，都是有助于更好地实现去中心化应用的关键技术。它们可以有效地管理合同，更有效地实现货币交易，并且可以更有效地确保合同的完整性。

① Introduction to blockchain technology, which programming languages ​​are involved

Go language

Go language (Golang) is a new language launched by Google in 2009 A programming language that reduces code complexity without sacrificing application performance. Rob Pike, chief software engineer at Google, said: "We developed Go because the difficulty of software development over the past 10 years or so has been frustrating."

In addition to Bitcoin being developed in C, At present, the clients of most mainstream workshops are developed with Go language, which is enough to show the status of Go language in the entire blockchain industry.

C

C further expands and improves the C language and is an object-oriented programming language. C runs on a variety of platforms, such as Windows, MAC operating systems, and various versions of UNIX. C is a very widely used computer programming language. It is a general programming language that supports multiple programming patterns, such as procedural programming, data abstraction, object-oriented programming, generic programming, and design patterns.

Most blockchain companies choose to use C to write the bottom layer of the blockchain. The most famous ones are Bitcoin, Ripple, etc., which mainly reflect strong computation.

Java

Java is different from general compiled languages ​​or interpreted languages. It first compiles the source code into bytecode, and then relies on virtual machines on various platforms to interpret and execute the bytecode, thereby achieving the cross-platform feature of "write once, run anywhere". The development of blockchain projects has obvious dependence on Java.

Others include Python, system architecture, Ethereum, Linux, hyperledger, JavaScript, etc. will be covered.

② Beijing Java course shares the consensus algorithm in blockchain technology

We have shared some explanations and analysis of knowledge points about blockchain technology with you many times. Today, in the Beijing Java course, we will learn about some basic definitions and characteristics of consensus algorithms in blockchain technology.

A brief look at the blockchain

The chain in our general ideology is an iron chain, made of iron. One link after another. Figuratively, the blockchain can also be understood in this way, except that it is not made of iron, but connected by blocks with a certain data structure. This is a simple prototype

Popular explanation of consensus

The so-called consensus, in layman’s terms, means that we all agree on the understanding of something. For example, we have daily meetings to discuss issues, or we can judge whether an animal is a cat. If we look at it with the naked eye and it looks like a cat, and it meets the characteristics of a cat, then we think it is a cat. Consensus, yesA rule.

Continue to use our meeting example. Participants in the meeting discuss and solve problems through meetings.

Compared with the blockchain, miners participating in mining use a certain consensus method (algorithm) to make their own ledger consistent with the ledgers of other nodes. The deeper meaning of keeping the ledger consistent is to keep the block information in the chain consistent.

Why is consensus needed? Is it possible to not need it? Of course not. Without the rules of consensus in life, everything will be chaotic. The blockchain loses consensus rules, and each node does its own thing, losing its consistent meaning.

The corresponding relationship between these two examples is as follows:

Meeting people = mining miners

Meeting = consensus method (algorithm)

Talk about solving problems = make your own ledger consistent with the ledgers of other nodes

If you don’t understand the concept of a node, please first understand it as a miner. A node contains many roles, and miners are one of them.

Consensus algorithm

Currently in the blockchain, nodes allow their own ledgers to match those of other nodes. There are several consensus methods (algorithms) that maintain consistency:

PoW, represented by Bitcoin (BTC)

Disadvantages:

The emergence of mining pools violates the original intention of decentralization to a certain extent, and also makes 51% attacks possible, affecting its security.

There is a huge waste of computing power. Look at the mining pool that consumes a lot of electricity resources. As the difficulty increases, not enough is mined to pay the electricity bill

PoS, represented by Ethereum (ETH), transition from PoW to PoS

Disadvantages:

The cost of attackers attacking the network is very low, and they can compete by owning tokens

In addition, nodes with a large number of tokens will have a higher probability of obtaining accounting rights. If it is large, the network consensus will be dominated by a few wealthy accounts, thus losing fairness.

③ Peking University Jade Bird Java Training: The organizational structure content that constitutes the basic computing function of the blockchain

With the rapid development of the Internet, consumers are increasingly concerned about the area. The awareness of blockchain technology and digital virtual currencies is also constantly increasing.
Today, let’s take a look at the structures of the basic computing methods of blockchain technology.
Let’s learn about the specific situation with the following java course http://www.kmbdqn.cn/.
The basic elements that make up computing technology are storage, processing and communication.
Mainframes, PCs, mobile devices, and cloud services all exhibit these elements in their own way.
There are also dedicated building blocks within each element to allocate resources.
This article focuses on the large framework of the blockchain: introducing the modules of each computing element in the blockchain and some implementation cases of each module, preferring an overview rather than a detailed explanation.
The building blocks of blockchain are the following are the building blocks of each computing element in decentralized technology: Storage: token storage, database, file system/blob processing: stateful business logic, stateless business logic, high Performance Computing Communication: Connecting Data, Value, and State Network Storage As a basic computing element, the storage part contains the following building blocks.
Token storage.
Tokens are storage media of value (such as assets, securities, etc.). The value can be bitcoins, air miles or the copyright of digital works.
The main function of the token storage system is to issue and transfer tokens (with multiple variants) while preventing events such as multiple payments from occurring.
Bitcoin and Zcash are two "pure" systems that only focus on the token itself.
Ethereum began to use tokens for various services to realize its ideal of serving as a global computing center.
These are examples where tokens are used as internal incentives to operate the entire network architecture.
There are also tokens that are not internal tools used by the network to promote its own operation, but are used as incentives for higher-level networks, but their tokens are actually stored in the underlying architecture.
One example is an ERC20 token like Golem, which runs on the Ethereum network layer.
Another example is Envoke’s IP authorization token, which runs on the IPDB network layer.
Database.
Databases are specifically designed to store structured metadata, such as data tables (relational databases), document storage (such as JSON), key-value storage, time series or graph databases.
Databases can quickly retrieve data using queries like SQL.
Traditional distributed (but centralized) databases such as MongoDB and Cassandra typically store hundreds of terabytes or even petabytes of data, with performance reaching millions of writes per second.
Query languages ​​like SQL are very powerful because they separate implementation from specifications so that they are not tied to a specific application.
SQL has been used as a standard for decades, so the same database system can be used in many different industries.
In other words, to discuss generality outside of Bitcoin, one does not necessarily have to talk about Turing completeness.
You only need one database, which is both concise and easy to expand.
There are times when Turing completeness is also very useful, which we will discuss in detail in the "Decentralized Processing" section.
BigchainDB is a decentralized database software and a specialized document storage system.
It is based on MongoDB (or RethinkDB) and inherits the latter'sQuery and expansion logic.
But it also has the characteristics of blockchain, such as decentralized control, tamper resistance and token support.
IPDB is a regulated public instance of BigchainDB.
In the field of blockchain, it can also be said that IOTA is a time series database.
File system/blob data storage.
These systems store large files (movies, music, large data sets) in a hierarchical structure of directories and files.
IPFS and Tahoe-LAFS are decentralized file systems that contain decentralized or centralized blob storage.
FileCoin, Storj, Sia and Tieron are decentralized blob storage systems, as is the ancient and excellent BitTorrent, although the latter uses a p2p system rather than a token.
Ethereum Swarm, Dat, and Swarm-JS basically support the above two methods.
Data Market.
This kind of system connects data owners (such as enterprises) with data users (such as AI startups).
They sit on top of databases and file systems, but they are still the core architecture because countless data-hungry applications (such as AI) rely on such services.
Ocean is an example of a protocol and network on which a data market can be created.
There are also application-specific data markets: EnigmaCatalyst for crypto markets, Datum for private data, and DataBrokerDAO for IoT data streams.
Processing Next we discuss processing this basic computational element.
"Smart contract" system usually refers to a system that processes data in a decentralized form [3].
It actually has two subsets with completely different properties: stateless (combined) business logic and stateful (sequential) business logic.
There is a huge difference between stateless and stateful in terms of complexity, verifiability, etc.
The three types of decentralized processing modules are High Performance Computing (HPC).
Stateless (combined) business logic.
This is arbitrary logic and does not retain state internally.
In electronic engineering terms, it can be understood as a combinational digital logic circuit.
This logic can be expressed as a truth table, a logic diagram, or code with conditional statements (a combination of if/then, and, or, not, etc. judgments).
Because they are stateless, it is easy to verify large stateless smart contracts, creating large verifiable and secure systems.
N inputs and one output require O(2^N) calculations to verify.
The Inter-Ledger Protocol (ILP) includes a crypto-conditions (CC) protocol to clearly label combinational circuits.
CC is easy to understand because it became an Internet standard through IETF, while ILP is in various centers and decentralizedIt is widely used in modern payment networks (such as Ripple used by more than 75 banks).
CC has many independently implemented versions, including JavaScript, Python, Java, etc.
BigchainDB, Ripple and other systems also use CC to support combined business logic/smart contracts.

④ How to add blockchain technology to javaweb

What is blockchain? Blockchain technology applications?

What is blockchain? Blockchain is essentially a decentralized distributed ledger database. It is the underlying technology of Bitcoin and is closely related to Bitcoin. The blockchain itself is actually a series of data blocks generated using cryptography. Each data block contains information that is effectively confirmed for multiple Bitcoin network transactions.

Whenever an encrypted transaction is generated, miners with powerful computing power in the network begin to use algorithms to decrypt and verify the transaction, creating new blocks to record the latest transaction. New blocks are linearly added to the end of the original blockchain in chronological order, and this ledger will continue to grow and extend.

Through the complex setting of public keys and private keys, the blockchain network broadcasts the ledger of all transactions in the entire financial network in real time, distributes transaction records to each client in real time, and also Ensure that each person can only make modifications to his or her own property. Of course, there are also other people's transaction records in the ledger. Although you can see the numerical value and the corresponding transaction address (basically this is composed of a lengthy period of scrambled letters and numbers), you have no way of knowing it without borrowing other technical means. The true identity of the trader.

What is blockchain? Since last year, the concept of blockchain has begun to become popular, especially in some developed countries, and it has received star-level popularity. Blockchain has also been dubbed as a subversion and has the potential to become popular all over the world. Blockchain will first impact the financial industry, and then affect the wider economic field. The prediction is based on several core features of the blockchain: decentralization, distributed ledger, point-to-point transmission, non-tampering, etc. Since the birth of blockchain is quite miraculous, and its development has also attracted attention with the rise of Bitcoin around the world, many people confuse the relationship between blockchain and Bitcoin. Some people think that blockchain and Bitcoin have a father-son relationship, and some people think that blockchain was born after Bitcoin. But in fact, blockchain is actually the underlying supporting technology of Bitcoin, which can be compared to TCP/IP in the Internet. protocol. From a certain perspective, Bitcoin can be seen as the first practical application of blockchain that emerged at the same time as blockchain.

Application of blockchain technology? Bubi Blockchain has been focusing on the R&D and innovation of blockchain technology and products since its establishment. It has a number of core technologies and has made substantial innovations in many aspects, forming a number of core technical achievements, such as: Mathematically proven distributed consensus technology, fastLarge-scale ledger access technology, multi-chain general ledger technology that supports business expansion, interconnection technology between heterogeneous blockchains, etc. On April 25, "Gege Points" introduced the concept of blockchain into the points system, jointly opened it up with multiple parties, issued and redeemed points, and promoted the circulation of points. Each cooperative institution can jointly participate in transaction verification, ledger storage, and real-time settlement; the third-party payment platform of the enterprise points issuer makes the entry and exit of points more flexible. Bubi has developed its own basic blockchain service platform, which has been applied in equity, supply chain, points, credit and other fields. Bubi has been committed to building an open value circulation network with decentralized trust as the core, allowing digital assets to flow freely.

What is blockchain? Blockchain technology applications? We can use Bitcoin to describe several application prospects of blockchain. Bitcoin can be said to be a decentralized currency or asset. Every Bitcoin can be traced and viewed by anyone at any time. This application prospect means that if transactions between people can return to the original form of barter exchange from the current currency as a means of measuring value, then the measure of value will no longer be legal currency, but Bitcoin or Measured by other virtual currencies or virtual assets generated by the blockchain, the benefits brought to us by the current sharing economy are just the tip of the iceberg. If this feature of Bitcoin that can be traced, queried and cannot be tampered with is applied to a credit record system, an identity authentication system or a property rights authentication system, then many things such as proving "Is this house my property?" "I am unmarried" "Still married" series of difficult questions will no longer exist at all. According to the current development trend, blockchain will not only reshape all aspects of money markets, payment systems, financial services and economic forms, but also change every field of human life.

⑤ What is the relationship between blockchain and Java?

What is blockchain? People are becoming more and more interested in blockchain, and people have also discovered that blockchain and Java There is an unusual relationship. What is the relationship between blockchain and Java? Let’s discuss it with Shahe IT Training today.

1. What is blockchain?

Blockchain is the underlying technology of Bitcoin, like a database ledger. Record all transactions. This technology has gradually attracted the attention of the banking and financial industries because of its safety and convenience. The blockchain is a series of data blocks generated using cryptographic methods. Each data block contains the information of all Bitcoin network transactions in the past ten minutes, which is used to verify the validity of its information (anti-counterfeiting) and generate the next A block.

2. What is the relationship between blockchain and Java?

We know that Java is a high-end computer development programming language , Java has the characteristics of simplicity, object-oriented, distributed, robustness, security, platform independence and portability, multi-threading, dynamics, etc., fromAnd is widely used by people. We can see that blockchain is a very important part of Bitcoin, and security requirements are particularly high, so Java is used to implement blockchain because of its unique characteristics.

We know that Java is the most widely used programming language in the world. From the perspective of Java application fields, it mainly manifests in three aspects: one is large and medium-sized commercial applications, and the other is desktop Applications (often referred to as c/s applications), and the third is applications in the mobile field. You haven't thought that Bitcoin, which is currently being speculated by everyone, is actually related to Java. It's no wonder that everyone prefers the Java programming language.

⑥ Beida Jade Bird Java Training: What issues need to be understood for blockchain technology security

I believe everyone should be familiar with blockchain technology, and Today we will take a look at what issues we need to pay attention to in the field of blockchain technology security. Let’s start with today’s main content.
Currently, most blockchain projects carried out within enterprises are so-called "private chains with permissions".
Unlike public chains, private chains can only be accessed by a selected group of users who have the authority to enter, verify, record and exchange data on the ledger.
Of course, such a network would be nearly impossible to break for an "outsider" who has never been allowed to join.
But with the emergence of private chains, another question arises: In order to improve privacy and security, do we really need to abandon decentralization? Written by Mike Orcutt from MIT Technology Review Dao, a private blockchain system "may make its owners feel more secure, but it really just gives them more control, meaning they can make changes regardless of whether other network participants agree.
" Such systems need to provide balancing mechanisms, grant different levels of permissions to different user groups, and perform identity checks on verifiers to ensure that they are who they claim to be.
That’s why many companies are looking for a way to have both—the decentralization of a public chain and the extra security of a private chain.
Consortium chains developed by major manufacturers such as IBM, Corda, and Ripple currently appear to be good security choices.
In short, they provide enterprises with access to a centralized system, and the system itself has a certain degree of cryptographic auditability and security.
Other enterprises are also considering how to adapt public chains to meet their security needs.
For example, the Ethereum blockchain already provides mechanisms that can be leveraged to ensure the privacy of network participants, including ring signatures, stealth addresses, and storing private data for both public and private blockchains.
In general, the blockchain field is moving steadily towards new solutions that define technology-granular privacy layers for public chains, private chains, and consortium chain networks.exhibition.
IT training http://www.kmbdqn.cn/ found that various companies are actively investigating and patching known vulnerabilities, and adopting new mechanisms to ensure that all parties are protected and that no malicious hackers can break through and Exploiting loopholes in the ledger.