{"id":4630,"date":"2019-10-21T00:55:50","date_gmt":"2019-10-20T15:55:50","guid":{"rendered":"https:\/\/chat-messenger.com\/?p=4630"},"modified":"2023-11-13T01:14:20","modified_gmt":"2023-11-12T16:14:20","slug":"phien-ban-java","status":"publish","type":"post","link":"https:\/\/chat-messenger.com\/vi\/blog\/java\/java-instanceof","title":{"rendered":"Java \u5909\u6570\u306e\u578b\u3092 instanceof \u3067\u78ba\u8a8d\u3059\u308b"},"content":{"rendered":"

Ki\u1ec3m tra ki\u1ec3u d\u1eef li\u1ec7u c\u1ee7a bi\u1ebfn.<\/h2>\n\n\n\n

Ch\u01b0\u01a1ng tr\u00ecnh v\u00ed d\u1ee5 n\u00e0y minh h\u1ecda c\u00e1ch ki\u1ec3m tra ki\u1ec3u d\u1eef li\u1ec7u c\u1ee7a m\u1ed9t bi\u1ebfn trong Java.<\/p>\n\n\n\n

Java l\u00e0 m\u1ed9t ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh ki\u1ec3u t\u0129nh, trong \u0111\u00f3 c\u00e1c ki\u1ec3u d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c khai b\u00e1o r\u00f5 r\u00e0ng, v\u00ec v\u1eady kh\u00f4ng c\u00f3 nhi\u1ec1u tr\u01b0\u1eddng h\u1ee3p c\u1ea7n ki\u1ec3m tra ki\u1ec3u. Tuy nhi\u00ean, khi s\u1eed d\u1ee5ng c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng k\u1ebf th\u1eeba, vi\u1ec7c ki\u1ec3m tra ki\u1ec3u c\u00f3 th\u1ec3 tr\u1edf n\u00ean c\u1ea7n thi\u1ebft.<\/p>\n\n\n\n

C\u00e1ch ki\u1ec3m tra ki\u1ec3u d\u1eef li\u1ec7u trong Java instanceof<\/strong> B\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng c\u00e1c to\u00e1n t\u1eed \u0111\u1ec3 \u0111\u00e1nh gi\u00e1 c\u00e1c l\u1edbp v\u00e0 giao di\u1ec7n b\u1eb1ng c\u00e2u l\u1ec7nh if, nh\u01b0 sau:<\/p>\n\n\n\n

\n

bi\u1ebfn \u0111\u1ed5i<\/em> instanceof \u30af\u30e9\u30b9<\/p>\n\n\n\n

bi\u1ebfn \u0111\u1ed5i<\/em> instanceof \u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9<\/p>\n<\/div><\/div>\n\n\n\n

instanceof<\/strong> B\u1ea1n c\u00f3 th\u1ec3 ch\u1ec9 \u0111\u1ecbnh t\u00ean l\u1edbp ho\u1eb7c t\u00ean giao di\u1ec7n \u1edf ph\u00eda b\u00ean ph\u1ea3i.instanceof<\/strong> Gi\u00e1 tr\u1ecb tr\u1ea3 v\u1ec1 l\u00e0 m\u1ed9t gi\u00e1 tr\u1ecb boolean, v\u00e0 n\u1ebfu gi\u00e1 tr\u1ecb \u0111\u00f3 l\u00e0 true, th\u00ec bi\u1ebfn \u0111\u00f3 ch\u00ednh l\u00e0 l\u1edbp ho\u1eb7c giao di\u1ec7n \u0111\u01b0\u1ee3c ch\u1ec9 \u0111\u1ecbnh.<\/p>\n\n\n\n

\n

Tr\u00f2 chuy\u1ec7n & Tin nh\u1eafn<\/a> \u0110\u00e2y l\u00e0 m\u1ed9t ph\u1ea7n m\u1ec1m c\u1ed9ng t\u00e1c t\u00edch h\u1ee3p, th\u00e2n thi\u1ec7n v\u1edbi ng\u01b0\u1eddi d\u00f9ng, k\u1ebft h\u1ee3p tr\u00f2 chuy\u1ec7n doanh nghi\u1ec7p, h\u1ed9i ngh\u1ecb tr\u1ef1c tuy\u1ebfn, chia s\u1ebb t\u1ec7p, qu\u1ea3n l\u00fd l\u1ecbch tr\u00ecnh, qu\u1ea3n l\u00fd t\u00e0i li\u1ec7u, \u0111\u1eb7t ph\u00f2ng h\u1ecdp v\u00e0 qu\u1ea3n l\u00fd \u0111i\u1ec3m danh. N\u00f3 c\u0169ng cung c\u1ea5p b\u1ea3o m\u1eadt m\u1ea1nh m\u1ebd cho doanh nghi\u1ec7p.Ho\u00e0n to\u00e0n mi\u1ec5n ph\u00ed!<\/mark><\/p>\n<\/a>\n<\/div>\n\n\n\n

Ch\u01b0\u01a1ng tr\u00ecnh m\u1eabu<\/h2>\n\n\n\n

Ch\u00fang ta h\u00e3y b\u1eaft \u0111\u1ea7u v\u1edbi m\u1eabu \u0111\u01a1n gi\u1ea3n nh\u1ea5t. N\u1ebfu bi\u1ebfn i l\u00e0 m\u1ed9t s\u1ed1 nguy\u00ean, n\u00f3 tr\u1ea3 v\u1ec1 true; ng\u01b0\u1ee3c l\u1ea1i, n\u00f3 tr\u1ea3 v\u1ec1 false.<\/p>\n\n\n\n

M\u00e3 v\u00ed d\u1ee5<\/h4>\n\n\n\n
public static void integerSample() {\n    Integer i = 100;\n    boolean result = i instanceof Integer;\n    System.out.println(result);\n}<\/code><\/pre><\/div>\n\n\n\n
K\u1ebft qu\u1ea3 \u0111\u1ea7u ra<\/h4>\n\n\n\n
true<\/code><\/pre><\/div>\n\n\n\n
\u5909\u6570 i \u306f Integer \u306a\u306e\u3067\u3001\u7d50\u679c\u306f true \u306b\u306a\u308a\u307e\u3059\u3002\u3057\u304b\u3057\u3001\u3053\u308c\u3067\u306f\u5f53\u305f\u308a\u524d\u3059\u304e\u3066 instanceof \u304c\u306a\u3093\u306e\u305f\u3081\u306b\u3042\u308b\u304b\u5206\u304b\u306a\u3044\u306e\u3067\u3001\u3082\u3046\u5c11\u3057\u8907\u96d1\u306b\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
instanceof \u306e\u52b9\u679c\u7684\u306a\u4f7f\u3044\u65b9<\/h2>\n\n\n\n
instanceof \u306e\u52b9\u679c\u7684\u306a\u4f7f\u3044\u65b9\u306e\u4e00\u3064\u306b\u3001\u305d\u306e\u5909\u6570\u304c\u3069\u306e\u5b50\u30af\u30e9\u30b9\u306a\u306e\u304b\u3092\u5224\u5b9a\u3059\u308b\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n
M\u00e3 v\u00ed d\u1ee5<\/h4>\n\n\n\n
\u0110o\u1ea1n m\u00e3 m\u1eabu t\u1ea1o ra m\u1ed9t l\u1edbp \u0111\u1ed9ng v\u1eadt c\u00f3 t\u00ean l\u00e0 Animal, v\u00e0 hai l\u1edbp Dog v\u00e0 Cat, k\u1ebf th\u1eeba t\u1eeb l\u1edbp Animal. Sau khi t\u1ea1o c\u00e1c th\u1ec3 hi\u1ec7n, ph\u01b0\u01a1ng th\u1ee9c `play` \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111\u1ecbnh ngh\u0129a c\u00e1c bi\u1ebfn. instanceof<\/strong> H\u1ec7 th\u1ed1ng s\u1ebd x\u00e1c \u0111\u1ecbnh \u0111i\u1ec1u n\u00e0y v\u00e0 ph\u00e2n nh\u00e1nh \u0111\u1ea7u ra c\u1ee7a b\u1ea3ng \u0111i\u1ec1u khi\u1ec3n cho ph\u00f9 h\u1ee3p. <\/p>\n\n\n\n
class Animal {} \nclass Dog extends Animal {}\nclass Cat extends Animal {}\n\npublic class Main {\n    public static void main(String[] args) {\n        instanceofSample();\n    }\n    \n    static void instanceofSample() {\n        Animal dog = new Dog();\n        play(dog);\n        Animal cat = new Cat();\n        play(cat);\n    }\n    \n    static void play(Animal animal) {\n        if (animal instanceof Dog) {\n            System.out.println("\u304a\u6563\u6b69\u3059\u308b");\n        } else {\n            System.out.println("\u732b\u3058\u3083\u3089\u3057\u3067\u904a\u3076");\n        }\n    }\n}<\/code><\/pre><\/div>\n\n\n\n
K\u1ebft qu\u1ea3 \u0111\u1ea7u ra<\/h4>\n\n\n\n
\u304a\u6563\u6b69\u3059\u308b\n\u732b\u3058\u3083\u3089\u3057\u3067\u904a\u3076<\/code><\/pre><\/div>\n\n\n\n
\u0110i\u1ec3m m\u1ea5u ch\u1ed1t l\u00e0 trong ph\u01b0\u01a1ng ph\u00e1p "ch\u01a1i", kh\u00f4ng th\u1ec3 bi\u1ebft \u0111\u01b0\u1ee3c "con v\u1eadt" \u0111\u01b0\u1ee3c d\u00f9ng l\u00e0m \u0111\u1ed1i s\u1ed1 l\u00e0 ch\u00f3 hay m\u00e8o.<\/p>\n\n\n\n
instanceof<\/strong> V\u00ec v\u1eady, do ch\u00fang ta c\u0169ng c\u00f3 th\u1ec3 ki\u1ec3m tra c\u00e1c tr\u01b0\u1eddng h\u1ee3p c\u1ee7a c\u00e1c l\u1edbp con (Dog ho\u1eb7c Cat) n\u1eb1m trong l\u1edbp cha (Animal), n\u00ean ch\u00fang ta c\u0169ng c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng n\u00f3 theo c\u00e1ch n\u00e0y.<\/p>\n\n\n\n
Ki\u1ec3m tra xem giao di\u1ec7n c\u1ee5 th\u1ec3 \u0111\u00f3 \u0111\u00e3 \u0111\u01b0\u1ee3c tri\u1ec3n khai hay ch\u01b0a.<\/h2>\n\n\n\n
instanceof \u306e\u5bfe\u8c61\u3068\u306a\u308b\u5909\u6570\u306b\u3001\u3042\u308b\u7279\u5b9a\u306e\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u304c\u5b9f\u88c5\u3055\u308c\u3066\u3044\u308b\u304b\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002\u4f8b\u3048\u3070\u3053\u306e\u3088\u3046\u306a\u4f7f\u3044\u65b9\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
M\u00e3 v\u00ed d\u1ee5<\/h4>\n\n\n\n
\u6b21\u306e\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u3067\u306f\u3001\u4f50\u85e4\u3055\u3093\u3001\u9234\u6728\u3055\u3093\u30af\u30e9\u30b9\u3092\u4f5c\u6210\u3057\u3001\u9234\u6728\u3055\u3093\u3060\u3051\u304c\u8eca\u3092\u6301\u3063\u3066\u3044\u308b\u60f3\u5b9a\u3067\u3001\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9 Car \u3092 implements \u3057\u3066\u3044\u307e\u3059\u3002goShopping() \u30e1\u30bd\u30c3\u30c9\u306f\u8cb7\u3044\u7269\u306b\u884c\u304f\u51e6\u7406\u3092\u4eee\u5b9a\u3057\u3066\u3044\u307e\u3059\u304c\u3001Car \u3092 implements \u3057\u3066\u3044\u308b\u304b\u3001instanceof \u3067\u5224\u5b9a\u3057\u3066\u30b3\u30f3\u30bd\u30fc\u30eb\u51fa\u529b\u3092\u5206\u5c90\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
interface Car {}\nclass Sato {}\nclass Suzuki implements Car {}\n\npublic class Main {\n    public static void main(String[] args) throws Exception {\n        instanceofSample();\n    }\n    \n    static void instanceofSample() {\n        Sato sato = new Sato();\n        goShopping(sato);\n\n        Suzuki suzuki = new Suzuki();\n        goShopping(suzuki);\n    }\n    \n    static void goShopping(Object human) {\n        if (human instanceof Car) {\n            System.out.println("\u8eca\u3067\u884c\u304f");\n        } else {\n            System.out.println("\u6b69\u3044\u3066\u884c\u304f");\n        }\n    }\n}<\/code><\/pre><\/div>\n\n\n\n
K\u1ebft qu\u1ea3 \u0111\u1ea7u ra:<\/h4>\n\n\n\n
\u6b69\u3044\u3066\u884c\u304f\n\u8eca\u3067\u884c\u304f<\/code><\/pre><\/div>\n\n\n\n
B\u1ea1n c\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng c\u00e1c nh\u00e1nh x\u1eed l\u00fd ph\u1ee5 thu\u1ed9c v\u00e0o vi\u1ec7c t\u00ednh n\u0103ng Car c\u00f3 \u0111\u01b0\u1ee3c tri\u1ec3n khai hay kh\u00f4ng.<\/p>","protected":false},"excerpt":{"rendered":"
\u5909\u6570\u306e\u578b\u3092\u78ba\u8a8d\u3059\u308b Java \u3067\u5909\u6570\u306e\u578b\u3092\u78ba\u8a8d\u3059\u308b\u30b5\u30f3\u30d7\u30eb\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002 Java \u306f\u578b\u3092\u660e\u793a\u7684\u306b\u5ba3 […]<\/p>\n","protected":false},"author":1,"featured_media":9054,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"swell_btn_cv_data":"","footnotes":""},"categories":[19],"tags":[],"class_list":["post-4630","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java"],"_links":{"self":[{"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/posts\/4630","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/comments?post=4630"}],"version-history":[{"count":6,"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/posts\/4630\/revisions"}],"predecessor-version":[{"id":9049,"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/posts\/4630\/revisions\/9049"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/media\/9054"}],"wp:attachment":[{"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/media?parent=4630"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/categories?post=4630"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chat-messenger.com\/vi\/wp-json\/wp\/v2\/tags?post=4630"}],"curies":[{"name":"trang web","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}