After following, you can keep track of his dynamic information in a timely manner
Usesystemctlstatusserviceorsystemctlis-activeservicetocheckaservice'sstate.2.Start,stop,restart,orreloadserviceswithsudosystemctlstart/stop/restart/reloadservice,orusereload-or-restartforsafeconfigupdates.3.Enableordisableservicesatbootusingsudosyste
Aug 07, 2025 pm 02:53 PM
Java9 introduced the Java module system (JPMS), aiming to achieve strong packaging, reliable dependency management and scalability through modularity; 1. The module declares required modules (requires) and export packages (exports) through module-info.java; 2. Provides strong packaging, default internal packages are not visible; 3. Enables reliable configuration and checks dependencies at startup; 4. Supports the use of jlink to create a streamlined runtime; 5. Pay attention to automatic modules, unnamed modules and prohibited split package issues; 6. You can gradually migrate and combine --add-opens and other options to deal with reflection requirements; ultimately, JPMS improves architectural clarity, security and maintenance, which is an important foundation for building robust Java applications.
Aug 07, 2025 pm 02:51 PM
Usearray_search()withunset()toremovethefirstoccurrenceofavalue,butnoteitdoesn’treindexthearray;2.Usearray_filter()toremoveallinstancesofavalue,whichautomaticallyreindexesnumericarraysandpreserveskeysinassociativearrays;3.Applystrictcomparisoninarray_
Aug 07, 2025 pm 02:50 PM
Java's switch expressions have become a standard feature since Java14, and can return values and have a simpler syntax than traditional switch statements. 1. Use the -> arrow syntax to avoid break and unexpected fall-through; 2. The compiler ensures that all possible values of enum and sealed types are processed to improve code security; 3. Use {} blocks to match yield to return values in complex logic. It is recommended to give priority to switch expressions in Java 14 and above. It not only reduces errors, but also makes the code clearer and more functional, suitable for value mapping, replaces long if-else chains and initialization variables. It is a substantial language upgrade rather than a simple syntactic sugar.
Aug 07, 2025 pm 02:43 PM
RxJS is used in Angular to handle asynchronous operations and component communication, which can improve code maintainability and responsiveness. 1. Use Observable to replace Promise to realize chain calls, combine multiple requests, and enhance data processing logic through operators such as map and switchMap; 2. Use Subject and BehaviorSubject to achieve cross-component communication, and BehaviorSubject retains the latest value for state sharing; 3. Use async pipeline in the template to automatically manage subscriptions to avoid duplicate requests and improve performance; 4. Use tap to debug stream data, and combine shareReplay cache results to reduce duplicate calls, and improve application efficiency. master
Aug 07, 2025 pm 02:41 PM
The core of writing clean JavaScript code is to improve readability, maintenance and collaboration efficiency. 1. Use meaningful variable names, such as createDate and userScores, to avoid fuzzy naming; 2. Functions should be small and focused, and each function should only do one thing, such as splitting processUser into multiple single responsibility functions; 3. Avoid Boolean flag parameters, and use explicit function names such as createTempFile and createConfigFile to improve readability; 4. Use default parameters and deconstruction to simplify function calls, such as createUser({name='Anonymous',age=0,role='user'}={})
Aug 07, 2025 pm 02:28 PM
Javagenericsprovidecompile-timetypesafetybutareerasedatruntimeduetotypeerasure.1.Typeerasureremovesgenerictypeinformationduringcompilation,replacingtypeparameterswithboundsorObjectandinsertingcasts.2.Wildcardslike?extendsTand?superTenableflexible,saf
Aug 07, 2025 pm 02:13 PM
Aninodeisadatastructurestoringfilemetadataexceptthenameanddata;eachfilehasoneinodewithauniquenumber,andfilenamesmaptoinodesviadirectoryentries.1.Usels-itoviewinodenumbersandstatfilenamefordetails.2.Checkinodeusagewithdf-i;fullinodespreventnewfilecrea
Aug 07, 2025 pm 02:03 PM
Remote debugging is implemented by adding JVM parameters and configuring the IDE. Specific steps: 1. Add the -agentlib:jdwp parameter at startup to enable JDWP, configure transport, server, suspend and address parameters; 2. Create a new remote debugging configuration in IntelliJIDEA or Eclipse, fill in the IP and port for connection; 3. Pay attention to avoid long-term activation of debug mode, use suspend=y with caution, prevent port conflicts, and improve debugging efficiency with logs.
Aug 07, 2025 pm 01:39 PM
SmartGuideshelpalignelementsindesignsoftwarebyshowingreal-timecues.Theydisplayedgealignment,spacingindicators,andcentermarkersasyoumoveobjects.Toenablethem:gotoView>SmartGuidesinAdobeIllustratororPhotoshop.Commonmistakesincludeworkingwithlockedlay
Aug 07, 2025 pm 01:20 PM
Select the official MongoDB driver that matches the main and backend languages; 2. Check the maturity and community activity of the driver, and give priority to those that are supported and maintained frequently; 3. Select synchronous or asynchronous drivers based on the application architecture, and decide whether to use ORM as needed to balance development speed and performance; 4. Consider team experience, familiarity with ORM can improve efficiency, but it is recommended to directly connect to native drivers in high-performance scenarios.
Aug 07, 2025 pm 12:54 PM
Using hashing to store small objects can improve performance because it reduces memory overhead and speeds up access. When storing large amounts of small data, use hash to merge fields to a single key, thereby sharing metadata, reducing the overhead of each field. For example, using 100 values as a separate key requires 100 complete object headers and hash only requires one key header; in addition, hash supports reading and writing by field without loading the entire object, such as Redis, HGET commands that can obtain a certain field individually and reduce network bandwidth consumption; finally, many systems provide atomic operations such as HINCRBY for safe incremental counters to ensure reliability in concurrent environments.
Aug 07, 2025 pm 12:47 PM
To introduce and use JavaScript to atomize the CSS framework, you need to install the dependencies and configure the build tool first, then directly control the style through the class name, and optimize the output to reduce volume. 1. Install frameworks such as Tailwind and related plug-ins, initialize the configuration file and set the content path; 2. Introduce framework instructions in global CSS; 3. Use combination class names, responsive prefixes and pseudo-class modifiers to write components; 4. Configure on-demand extraction mechanism (such as PurgeCSS) to delete unused styles and compress output; 5. You can close some modules or use @apply to improve maintainability and team collaboration efficiency.
Aug 07, 2025 pm 12:44 PM
Enable Proton: Turn on SteamPlay in Steam settings and select the latest stable version of Proton; 2. Install Windows games: Install non-native games directly through the Steam store, Proton automatically handles compatibility; 3. Optimize performance: Use appropriate GPU drivers, install Vulkan support, enable GameMode and select a low-latency kernel; 4. Troubleshooting problems: refer to ProtonDB suggestions, replace Proton version, add startup options, or install GE-Proton to improve compatibility, so that thousands of Windows games can be run smoothly on Linux, without dual systems or additional devices, and the performance is close to Windows.
Aug 07, 2025 pm 12:39 PM
Use array_column and array_multisort to efficiently sort multidimensional arrays: 1. Use array_column to extract the target columns (such as age or name) to generate sorting basis; 2. Pass the extracted columns into array_multisort with the original array, sorting them in the specified order (SORT_ASC or SORT_DESC), and supports multi-field priority sorting; 3. The original array will automatically rearrange according to the sorting result of the extracted columns to maintain data association, without manually writing comparison functions, which is suitable for the processing of database or JSON data.
Aug 07, 2025 pm 12:04 PM
ChooseGraphQLifclientsneedflexibledataandyou'rebuildingcomplexUIs;stickwithRESTforpredictabledataneeds.2.GraphQLreducesrequestswithnestedqueries,idealformobileapps;RESTworkswhenendpointsareoptimized.3.RESTexcelsincachingviaHTTP/CDN;GraphQLrequiresadv
Aug 07, 2025 pm 12:00 PM
PHPcoercesarraykeystointegersorstrings,convertingbooleanstointegers(true→1,false→0).2.Floatsaretruncatedtointegers(3.9→3).3.Nullkeysbecomeemptystrings.4.Numericstringslike'42'areconvertedtointegers,causing$array['42']and$array[42]torefertothesameelem
Aug 07, 2025 am 11:55 AM
useMemo is used to cache expensive calculation results and avoid repeated execution; useCallback is used to keep function references stable and prevent unnecessary rendering of child components. 1. Use useMemo when there is high overhead calculation and few dependencies change; 2. Use useCallback when passing the function as a prop to a React.memo-based child component; 3. Both should not be overused and introduced only when performance issues are clear to avoid adding unnecessary memory overhead and complexity. Correctly setting dependency arrays and combining lint rules can prevent common errors. The ultimate goal is to reasonably weigh CPU and memory and improve application performance.
Aug 07, 2025 am 11:21 AM
Use Repository and UnitofWork mode to solve the problem of coupling business logic and data access in EFCore; 2. Repository mode abstracts data operations through the IRepository interface; 3. UnitofWork mode coordinates multiple Repository through IUnitOfWork and submits transactions; 4. Register DbContext and UnitOfWork in dependency injection to achieve service decoupling; 5. Call Repository and CompleteAsync() in service by injecting IUnitOfWork; 6. This mode is suitable for large applications and high-testing requirements scenarios, but
Aug 07, 2025 am 10:19 AM
The CI/CD of Python projects can significantly improve development efficiency and reduce the probability of errors. The appropriate platform should be selected according to the code repository: GitHubActions are used for GitHub projects, GitLab is used for GitLabCI, and you can choose Jenkins or AzurePipelines in enterprise-level requirements. When configuring, you need to ensure that the platform supports Python environment and dependent installation. Automated testing is the core, which should include installation dependencies, running unit tests, checking code style and coverage detection. The deployment method depends on the project type. Web applications can be deployed to Heroku, AWSElasticBeanstalk, etc., library projects upload PyPI, script tools push the server and set the time
Aug 07, 2025 am 09:31 AM
KVMisaLinuxkernel-basedhypervisorthatuseshardwarevirtualization(IntelVT-x/AMD-V)forrunningVMswithnear-nativeperformancebycombiningtheKVMkernelmoduleforlow-levelsupport,QEMUfordeviceemulation,andlibvirtformanagement.2.TosetupKVM,verifyCPUvirtualizatio
Aug 07, 2025 am 09:29 AM
Final is a keyword used in Java to restrict variables, methods and class modification, but it is not equivalent to immutability; 2. Final variables cannot be reassigned after initialization, but the content of the referenced object can still be changed; 3. Final method cannot be rewritten by subclasses, and final class cannot be inherited; 4. immutability refers to the object state immutable after creation, and needs to be implemented by declaring the class as final, the field as privatefinal, and no modification method is provided; 5. Final helps to implement immutability, but only when the referenced object itself is immutable, the entire object is truly immutable; 6. Immutable object is thread-safe,
Aug 07, 2025 am 09:24 AM
UseMongoDB’sbuilt-intoolslikemongostatforreal-timeperformancestatsandmongotoptotrackcollection-levelread/writetimes.2.Enabledatabaseprofilingwithdb.setProfilingLevel(1,{slowms:100})tologslowqueriesandidentifyperformanceissueslikeCOLLSCANormissinginde
Aug 07, 2025 am 09:15 AM
$_POSTisemptywhenreceivingJSONbecauseitonlyparsesform-encodeddata,notJSONpayloads;2.ToaccessJSONdata,usefile_get_contents('php://input')toreadtherawrequestbody;3.DecodetheJSONwithjson_decode()andvalidateusingjson_last_error();4.Thismethodisnecessaryf
Aug 07, 2025 am 08:53 AM
There are three ways to exclude specific categories in WordPress: use query_posts(), use the pre_get_posts hook, or use the plug-in. First, use query_posts() to directly modify the main loop query in the template file, such as query_posts(array('category__not_in'=>array(3,5))), which is suitable for temporary adjustment but may affect paging; second, it is safer to add functions in functions.php through the pre_get_posts hook. For example, excluding the specified classification ID when judging the home page main loop, it will not affect other page logic; finally, WPCate can be used
Aug 07, 2025 am 08:45 AM
Copyelision is a compiler optimization technique in C that avoids unnecessary object copying. The core idea is: in some scenarios, even if the code seems to require the call to copy or move the constructor, the compiler can skip this step and directly construct the target object. Common trigger scenarios include return value optimization (RVO), named return value optimization (NRVO), and initializing new objects with temporary objects. C 17 and later standards mandate the implementation of copyelision for some situations. Notes include: It is usually optional optimization, side effects such as constructor logs may not be executed, and different compilers may behave differently. You can verify that optimization occurs through constructor printing, debugging tools, or assembly code.
Aug 07, 2025 am 08:39 AM
To configure syslogdaemon, you must first confirm the service type, and then modify the rules and forwarding settings. 1. Use ps or systemctl to confirm using rsyslog or syslog-ng; 2. Edit /etc/rsyslog.conf to add log classification rules such as auth./var/log/auth.log; 3. Add forwarding rules to the client.*@@Remote IP:514 and enable the listening module on the server; 4. Configure the log rotation policy through logrotate, such as daily rotation for 7 days, and finally restart the service and check the firewall and permissions issues.
Aug 07, 2025 am 08:37 AM
WebPushNotificationscanbeimplementedbyfollowingthesesteps:1.CheckbrowsersupportandensureHTTPSisused;2.Setupaserviceworkertohandlepusheventsandnotificationclicks;3.Requestuserpermissionviaauser-initiatedaction;4.SubscribetheuserusingVAPIDkeys,converti
Aug 07, 2025 am 08:15 AM
Two-waydatabindinginVue.jsisachievedusingthev-modeldirective,whichautomaticallysynchronizesdatabetweenthemodelandtheview.1.v-modelissyntacticsugarforcombining:valueand@inputtocreateatwo-wayupdateloop.2.Itworksnativelywithformelementslikeinputs,checkb
Aug 07, 2025 am 08:10 AM
Use array_map for pure data conversion, and use foreach to deal with complex logic or side effects; 1. Use array_map first when converting each element uniformly; 2. Use foreach when it involves conditional judgment, status update, early exit or key-value operations; 3. You can combine array_filter and array_map to achieve clear chain processing; 4. Avoid using side effects in array_map to maintain code readability; choices should be based on intention rather than performance, and the two are complementary rather than mutually exclusive.
Aug 07, 2025 am 08:04 AM
