php: The difference between require_once and require

The settings.json file is located in the user-level or workspace-level path and is used to customize VSCode settings. 1. User-level path: Windows is C:\Users\\AppData\Roaming\Code\User\settings.json, macOS is /Users//Library/ApplicationSupport/Code/User/settings.json, Linux is /home//.config/Code/User/settings.json; 2. Workspace-level path: .vscode/settings in the project root directory

Through its Turing-complete smart contracts, EVM virtual machines and Gas mechanisms, Ethereum has built a programmable blockchain platform beyond Bitcoin, supporting diversified application ecosystems such as DeFi and NFT; its core advantages include a rich DApp ecosystem, strong programmability, active developer community and cross-chain interoperability; it is currently implementing consensus transformation from PoW to PoS through the upgrade of Ethereum 2.0, introducing beacon chains, verifier mechanisms and punishment systems to improve energy efficiency, security and decentralization; in the future, it will rely on sharding technology to realize data sharding and parallel processing, greatly improving throughput; at the same time, Rollup technology has been widely used as a Layer 2 solution, Optimistic Rollup and ZK-Rollu

There are four main ways to obtain BTC: 1. Register and exchange it with fiat currency or other digital assets through centralized trading platforms such as Binance, OK, Huobi, and Gate.io; 2. Participate in P2P platforms to directly trade with individuals, and pay attention to the credit risks of the counterparty; 3. Provide goods or services to accept BTC as payment; 4. Participate in airdrops, competitions and other platform reward activities to obtain a small amount of BTC. The core difference between BTC and digital currency is: 1. BTC is a type of digital currency, which belongs to a genus relationship; 2. BTC adopts a proof of work (PoW) mechanism, while other digital currencies may use various technologies such as proof of stake (PoS); 3. BTC emphasizes the value storage function of "digital gold", and other digital currencies may focus on payment efficiency or

Use performance analysis tools to locate bottlenecks, use VisualVM or JProfiler in the development and testing stage, and give priority to Async-Profiler in the production environment; 2. Reduce object creation, reuse objects, use StringBuilder to replace string splicing, and select appropriate GC strategies; 3. Optimize collection usage, select and preset initial capacity according to the scene; 4. Optimize concurrency, use concurrent collections, reduce lock granularity, and set thread pool reasonably; 5. Tune JVM parameters, set reasonable heap size and low-latency garbage collector and enable GC logs; 6. Avoid reflection at the code level, replace wrapper classes with basic types, delay initialization, and use final and static; 7. Continuous performance testing and monitoring, combined with JMH

HTTP log middleware in Go can record request methods, paths, client IP and time-consuming. 1. Use http.HandlerFunc to wrap the processor, 2. Record the start time and end time before and after calling next.ServeHTTP, 3. Get the real client IP through r.RemoteAddr and X-Forwarded-For headers, 4. Use log.Printf to output request logs, 5. Apply the middleware to ServeMux to implement global logging. The complete sample code has been verified to run and is suitable for starting a small and medium-sized project. The extension suggestions include capturing status codes, supporting JSON logs and request ID tracking.

TestthePDFinanotherapptodetermineiftheissueiswiththefileorEdge.2.Enablethebuilt-inPDFviewerbyturningoff"AlwaysopenPDFfilesexternally"and"DownloadPDFfiles"inEdgesettings.3.Clearbrowsingdataincludingcookiesandcachedfilestoresolveren

UseGuzzleforrobustHTTPrequestswithheadersandtimeouts.2.ParseHTMLefficientlywithSymfonyDomCrawlerusingCSSselectors.3.HandleJavaScript-heavysitesbyintegratingPuppeteerviaPHPexec()torenderpages.4.Respectrobots.txt,adddelays,rotateuseragents,anduseproxie

Blockchain is a distributed and decentralized digital ledger technology. Its core principles include: 1. Distributed ledger ensures that data is stored simultaneously on all nodes; 2. Encryption technology, linking blocks through hash values to ensure that data is not tampered with; 3. Consensus mechanisms, such as PoW or PoS, ensure that transactions are agreed between nodes; 4. Decentralization, eliminating single point of control, enhancing censorship resistance; 5. Smart contracts, protocols for automated execution. Cryptocurrencies are digital assets issued based on blockchain. The operation process is: 1. The user initiates transactions and signs digitally; 2. The transactions are broadcast to the network; 3. The miner or verifier verifies the validity of the transaction; 4. Multiple transactions are packaged into new blocks; 5. Confirm the new zone through consensus mechanism