{"id":8029,"date":"2023-04-06T00:00:00","date_gmt":"2023-04-06T00:00:00","guid":{"rendered":"http:\/\/soubory.info\/znalost\/komplexni-pruvodce-vytvarenim-casovacu-v-jazyce-java-prehled-osvedcenych-postupu\/"},"modified":"2023-04-06T00:00:00","modified_gmt":"2023-04-06T00:00:00","slug":"komplexni-pruvodce-vytvarenim-casovacu-v-jazyce-java-prehled-osvedcenych-postupu","status":"publish","type":"post","link":"https:\/\/soubory.info\/znalost\/komplexni-pruvodce-vytvarenim-casovacu-v-jazyce-java-prehled-osvedcenych-postupu\/","title":{"rendered":"Komplexn\u00ed pr\u016fvodce vytv\u00e1\u0159en\u00edm \u010dasova\u010d\u016f v jazyce Java: P\u0159ehled osv\u011bd\u010den\u00fdch postup\u016f"},"content":{"rendered":"
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<\/div>\n
\u00davod do \u010dasova\u010d\u016f v Jav\u011b<\/div>\n

Vytvo\u0159en\u00ed \u010dasova\u010de v Jav\u011b m\u016f\u017ee b\u00fdt slo\u017eit\u00e9, pokud nezn\u00e1te osv\u011bd\u010den\u00e9 postupy. Tento \u010dl\u00e1nek poskytne p\u0159ehled o r\u016fzn\u00fdch sou\u010d\u00e1stech \u010dasova\u010d\u016f v jazyce Java a o tom, jak efektivn\u011b vytv\u00e1\u0159et \u010dasova\u010de, abyste dos\u00e1hli maxim\u00e1ln\u00ed efektivity sv\u00e9ho k\u00f3du. <\/p>\n

<\/div>\n
P\u0159ehled \u010dasova\u010d\u016f v jazyce Java<\/div>\n

Ne\u017e se pust\u00edme do podrobnost\u00ed o vytv\u00e1\u0159en\u00ed \u010dasova\u010de v jazyce Java, je d\u016fle\u017eit\u00e9 m\u00edt p\u0159ehled o tom, co je to \u010dasova\u010d a jak funguje. \u010casova\u010d je v jazyce Java vl\u00e1kno, kter\u00e9 slou\u017e\u00ed k prov\u00e1d\u011bn\u00ed k\u00f3du v p\u0159edem stanoven\u00e9m \u010dase. To je u\u017eite\u010dn\u00e9 pro pl\u00e1nov\u00e1n\u00ed \u00faloh, kter\u00e9 maj\u00ed b\u00fdt provedeny v ur\u010dit\u00fd \u010das, nebo pro periodick\u00e9 spou\u0161t\u011bn\u00ed procesu. <\/p>\n

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V\u00fdhody \u010dasova\u010d\u016f v jazyce Java<\/div>\n

Pou\u017eit\u00ed \u010dasova\u010d\u016f v jazyce Java m\u016f\u017ee b\u00fdt p\u0159\u00ednosn\u00e9 v mnoha ohledech. Umo\u017e\u0148uje prov\u00e1d\u011bt k\u00f3d v ur\u010dit\u00fd \u010das nebo periodicky, ani\u017e byste to museli d\u011blat ru\u010dn\u011b. Umo\u017e\u0148uje tak\u00e9 nastavit \u00falohy, kter\u00e9 lze spustit p\u0159i spln\u011bn\u00ed ur\u010dit\u00fdch podm\u00ednek, nap\u0159\u00edklad po uplynut\u00ed ur\u010dit\u00e9ho \u010dasu nebo po v\u00fdskytu ur\u010dit\u00e9 ud\u00e1losti. <\/p>\n

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Vytvo\u0159en\u00ed \u010dasova\u010de v jazyce Java<\/div>\n

Jakmile jste se sezn\u00e1mili s \u010dasova\u010di v jazyce Java, je \u010das p\u0159ej\u00edt ke konkr\u00e9tn\u00edm postup\u016fm, jak \u010dasova\u010d vytvo\u0159it. Existuje n\u011bkolik r\u016fzn\u00fdch zp\u016fsob\u016f, jak vytvo\u0159it \u010dasova\u010d v jazyce Java, v\u010detn\u011b pou\u017eit\u00ed t\u0159\u00eddy Timer, ScheduledExecutorService nebo ScheduledThreadPoolExecutor. V\u0161echny tyto zp\u016fsoby maj\u00ed sv\u00e9 v\u00fdhody a nev\u00fdhody, proto je d\u016fle\u017eit\u00e9 p\u0159ed rozhodnut\u00edm porozum\u011bt ka\u017ed\u00e9mu z nich. <\/p>\n

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Porozum\u011bn\u00ed t\u0159\u00edd\u011b Timer<\/div>\n

T\u0159\u00edda Timer p\u0159edstavuje nejz\u00e1kladn\u011bj\u0161\u00ed zp\u016fsob, jak v jazyce Java vytvo\u0159it \u010dasova\u010d. Poskytuje metody pro vytv\u00e1\u0159en\u00ed a pl\u00e1nov\u00e1n\u00ed \u00faloh, kter\u00e9 maj\u00ed b\u00fdt provedeny v p\u0159edem ur\u010den\u00fd \u010das. Poskytuje tak\u00e9 metody pro zru\u0161en\u00ed a zm\u011bnu pl\u00e1nu \u00faloh. <\/p>\n

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Pou\u017eit\u00ed t\u0159\u00eddy ScheduledExecutorService<\/div>\n

T\u0159\u00edda ScheduledExecutorService p\u0159edstavuje pokro\u010dilej\u0161\u00ed zp\u016fsob vytvo\u0159en\u00ed \u010dasova\u010de v jazyce Java. Poskytuje v\u011bt\u0161\u00ed kontrolu nad zp\u016fsobem pl\u00e1nov\u00e1n\u00ed a spou\u0161t\u011bn\u00ed \u00faloh. Poskytuje tak\u00e9 v\u011bt\u0161\u00ed flexibilitu, pokud jde o pl\u00e1nov\u00e1n\u00ed \u00faloh, nap\u0159\u00edklad napl\u00e1nov\u00e1n\u00ed \u00falohy tak, aby se spou\u0161t\u011bla pravideln\u011b nebo pouze p\u0159i spln\u011bn\u00ed ur\u010dit\u00fdch podm\u00ednek. <\/p>\n

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Vyu\u017eit\u00ed ScheduledThreadPoolExecutor<\/div>\n

ScheduledThreadPoolExecutor je slo\u017eit\u011bj\u0161\u00ed zp\u016fsob vytvo\u0159en\u00ed \u010dasova\u010de v jazyce Java. Umo\u017e\u0148uje vytv\u00e1\u0159et a pl\u00e1novat \u00falohy, kter\u00e9 se maj\u00ed spustit v p\u0159edem stanoven\u00fd \u010das, ale tak\u00e9 umo\u017e\u0148uje vytv\u00e1\u0159et a pl\u00e1novat \u00falohy, kter\u00e9 se maj\u00ed spou\u0161t\u011bt pravideln\u011b nebo pouze p\u0159i spln\u011bn\u00ed ur\u010dit\u00fdch podm\u00ednek. <\/p>\n

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Doporu\u010den\u00e9 postupy pro vytv\u00e1\u0159en\u00ed \u010dasova\u010d\u016f v jazyce Java<\/div>\n

P\u0159i vytv\u00e1\u0159en\u00ed \u010dasova\u010de v jazyce Java je t\u0159eba dodr\u017eovat n\u011bkter\u00e9 doporu\u010den\u00e9 postupy. Je d\u016fle\u017eit\u00e9 pou\u017e\u00edt spr\u00e1vn\u00fd typ \u010dasova\u010de pro danou \u00falohu, proto\u017ee ka\u017ed\u00fd typ m\u00e1 sv\u00e9 v\u00fdhody a nev\u00fdhody. Je tak\u00e9 d\u016fle\u017eit\u00e9 pou\u017e\u00edt vhodn\u00e9 metody pro pl\u00e1nov\u00e1n\u00ed \u00faloh, proto\u017ee n\u011bkter\u00e9 metody jsou efektivn\u011bj\u0161\u00ed ne\u017e jin\u00e9. V neposledn\u00ed \u0159ad\u011b je d\u016fle\u017eit\u00e9 m\u00edt na pam\u011bti p\u0159\u00edpadn\u00e9 probl\u00e9my, kter\u00e9 mohou s \u010dasova\u010dem nastat, jako je nap\u0159\u00edklad prov\u00e1d\u011bn\u00ed \u00faloh v nespr\u00e1vn\u00fd \u010das nebo ztr\u00e1ta \u00faloh v d\u016fsledku p\u0159eru\u0161en\u00ed v syst\u00e9mu. <\/p><\/div>\n

\n
FAQ<\/div>\n
\n
M\u00e1 Java \u010dasova\u010d?<\/div>\n

Java m\u00e1 t\u0159\u00eddu Timer, kterou lze pou\u017e\u00edt k napl\u00e1nov\u00e1n\u00ed \u00faloh k proveden\u00ed v pozd\u011bj\u0161\u00edm \u010dase. To m\u016f\u017ee b\u00fdt u\u017eite\u010dn\u00e9 pro \u00falohy, kter\u00e9 je t\u0159eba prov\u00e1d\u011bt pravideln\u011b, jako je kontrola nov\u00fdch e-mailov\u00fdch zpr\u00e1v nebo obnoven\u00ed webov\u00e9 str\u00e1nky. <\/p>\n<\/div>\n

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Jak vytvo\u0159it vl\u00e1kno Timer v jazyce Java?<\/div>\n

Vl\u00e1kno Timer lze v jazyce Java vytvo\u0159it mnoha zp\u016fsoby. Jedn\u00edm ze zp\u016fsob\u016f je pou\u017eit\u00ed t\u0159\u00eddy java.util.Timer. Tato t\u0159\u00edda poskytuje vl\u00e1kn\u016fm mo\u017enost pl\u00e1novat \u00falohy k budouc\u00edmu proveden\u00ed ve vl\u00e1kn\u011b na pozad\u00ed. \u00dalohy lze napl\u00e1novat pro jednor\u00e1zov\u00e9 proveden\u00ed nebo pro opakovan\u00e9 prov\u00e1d\u011bn\u00ed v pravideln\u00fdch intervalech. <\/p>\n

<\/div>\n

Dal\u0161\u00edm zp\u016fsobem vytvo\u0159en\u00ed vl\u00e1kna Timer je pou\u017eit\u00ed t\u0159\u00eddy java.lang.Thread. T\u0159\u00edda Thread poskytuje metodu run, kterou lze pou\u017e\u00edt k proveden\u00ed \u00falohy v samostatn\u00e9m vl\u00e1kn\u011b. Chcete-li tuto metodu pou\u017e\u00edt, mus\u00edte vytvo\u0159it nov\u00fd objekt Thread a p\u0159edat mu \u00falohu, kter\u00e1 se m\u00e1 prov\u00e9st. Po vyvol\u00e1n\u00ed metody Thread.run bude \u00faloha provedena v samostatn\u00e9m vl\u00e1kn\u011b. <\/p>\n

<\/div>\n

Nakonec m\u016f\u017eete tak\u00e9 pou\u017e\u00edt rozhran\u00ed java.util.concurrent.ScheduledExecutorService pro pl\u00e1nov\u00e1n\u00ed \u00faloh k proveden\u00ed ve vl\u00e1kn\u011b na pozad\u00ed. Toto rozhran\u00ed poskytuje \u0159adu metod pro pl\u00e1nov\u00e1n\u00ed \u00faloh, v\u010detn\u011b metod pro pl\u00e1nov\u00e1n\u00ed \u00faloh pro jednor\u00e1zov\u00e9 proveden\u00ed nebo pro opakovan\u00e9 prov\u00e1d\u011bn\u00ed v pravideln\u00fdch intervalech. <\/p>\n<\/div>\n

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Jak vytvo\u0159it stopky v jazyce Java?<\/div>\n

Existuje n\u011bkolik r\u016fzn\u00fdch zp\u016fsob\u016f, jak lze v jazyce Java vytvo\u0159it stopky. Jedn\u00edm ze zp\u016fsob\u016f je pou\u017eit\u00ed soubor\u016f java.util.Timer a java.util. TimerTask. Dal\u0161\u00edm zp\u016fsobem je pou\u017eit\u00ed metody System.currentTimeMillis(). <\/p>\n

<\/div>\n

Pokud chcete pou\u017e\u00edt t\u0159\u00eddy Timer a TimerTask, m\u016f\u017eete vytvo\u0159it objekt Timer a pot\u00e9 vytvo\u0159it objekt TimerTask a p\u0159edat jej metod\u011b schedule() objektu Timer. Objekt TimerTask bude m\u00edt metodu run(), kterou m\u016f\u017eete pou\u017e\u00edt k tomu, co chcete, aby stopky d\u011blaly. Nap\u0159\u00edklad m\u016f\u017eete nechat metodu run() vypisovat aktu\u00e1ln\u00ed \u010das ka\u017edou sekundu. <\/p>\n

<\/div>\n

Pokud chcete pou\u017e\u00edt metodu System.currentTimeMillis(), m\u016f\u017eete vytvo\u0159it prom\u011bnnou long a na za\u010d\u00e1tku programu ji nastavit na hodnotu System.currentTimeMillis(). Pak poka\u017ed\u00e9, kdy\u017e chcete zjistit aktu\u00e1ln\u00ed \u010das, sta\u010d\u00ed zavolat System.currentTimeMillis() a ode\u010d\u00edst od n\u011bj po\u010d\u00e1te\u010dn\u00ed \u010das. T\u00edm z\u00edsk\u00e1te po\u010det milisekund, kter\u00e9 uplynuly od spu\u0161t\u011bn\u00ed va\u0161eho programu. <\/p>\n<\/div>\n

\n
Jak p\u0159id\u00e1m do sv\u00e9ho k\u00f3du \u010dasova\u010d?<\/div>\n

Chcete-li do sv\u00e9ho k\u00f3du p\u0159idat \u010dasova\u010d, mus\u00edte nejprve p\u0159idat n\u00e1sleduj\u00edc\u00ed p\u0159\u00edkaz using: <\/p>\n

<\/div>\n

using System.Timers; <\/p>\n

<\/div>\n

Jakmile tak u\u010din\u00edte, m\u016f\u017eete deklarovat objekt Timer n\u00e1sleduj\u00edc\u00edm zp\u016fsobem: <\/p>\n

<\/div>\n

Timer timer = new Timer(); <\/p>\n

<\/div>\n

Pot\u00e9 m\u016f\u017eete nastavit interval, ve kter\u00e9m m\u00e1 Timer spou\u0161t\u011bt ud\u00e1lost Tick, a to nastaven\u00edm vlastnosti Interval: <\/p>\n

<\/div>\n

timer.Interval = 1000; \/\/Vyvolat ud\u00e1lost Tick ka\u017edou 1 sekundu <\/p>\n

<\/div>\n

Nakonec budete muset k ud\u00e1losti Tick \u010dasova\u010de p\u0159ipojit obsluhu ud\u00e1losti, abyste mohli dost\u00e1vat ozn\u00e1men\u00ed, kdy\u017e se \u010dasova\u010d spust\u00ed: <\/p>\n

<\/div>\n

timer.Tick += Timer_Tick; <\/p>\n

<\/div>\n

Obsluha ud\u00e1losti Timer_Tick se spust\u00ed v\u017edy, kdy\u017e uplyne interval Timeru.<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

\u00davod do \u010dasova\u010d\u016f v Jav\u011b Vytvo\u0159en\u00ed \u010dasova\u010de v Jav\u011b m\u016f\u017ee b\u00fdt slo\u017eit\u00e9, pokud nezn\u00e1te osv\u011bd\u010den\u00e9 postupy. Tento \u010dl\u00e1nek poskytne p\u0159ehled o r\u016fzn\u00fdch sou\u010d\u00e1stech \u010dasova\u010d\u016f v jazyce Java a o tom, jak efektivn\u011b vytv\u00e1\u0159et \u010dasova\u010de, abyste dos\u00e1hli maxim\u00e1ln\u00ed efektivity sv\u00e9ho k\u00f3du. P\u0159ehled \u010dasova\u010d\u016f v jazyce Java Ne\u017e se pust\u00edme do podrobnost\u00ed o vytv\u00e1\u0159en\u00ed \u010dasova\u010de v jazyce … \u010c\u00edst d\u00e1l<\/a><\/p>\n","protected":false},"author":3970,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-8029","post","type-post","status-publish","format-standard","hentry","category-zalozeni-nove-firmy"],"_links":{"self":[{"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/posts\/8029","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/users\/3970"}],"replies":[{"embeddable":true,"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/comments?post=8029"}],"version-history":[{"count":0,"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/posts\/8029\/revisions"}],"wp:attachment":[{"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/media?parent=8029"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/categories?post=8029"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/soubory.info\/znalost\/wp-json\/wp\/v2\/tags?post=8029"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}