{"id":660,"date":"2020-07-22T13:29:24","date_gmt":"2020-07-22T06:29:24","guid":{"rendered":"https:\/\/www.marketenterprise.vn\/blog\/?p=660"},"modified":"2021-12-27T19:59:09","modified_gmt":"2021-12-27T12:59:09","slug":"tinh-da-hinh-trong-oop","status":"publish","type":"post","link":"https:\/\/www.marketenterprise.vn\/blog\/tinh-da-hinh-trong-oop.html","title":{"rendered":"T\u00ednh \u0111a h\u00ecnh (Polymorphism) trong l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng"},"content":{"rendered":"

<\/h4>\n

4 \u0111\u0103\u0323c ti\u0301nh cu\u0309a l\u00e2\u0323p tri\u0300nh h\u01b0\u01a1\u0301ng \u0111\u00f4\u0301i t\u01b0\u01a1\u0323ng (Object Oriented Programming)<\/h2>\n
    \n
  1. Ti\u0301nh \u0111o\u0301ng go\u0301i (Encapsulation)<\/strong><\/a><\/li>\n
  2. T\u00ednh k\u1ebf th\u1eeba (Inheritance)<\/strong><\/a><\/li>\n
  3. T\u00ednh \u0111a h\u00ecnh (Polymorphism)<\/strong><\/a><\/li>\n
  4. T\u00ednh tr\u1eebu t\u01b0\u1ee3ng (Abstraction)
    \n<\/strong><\/li>\n<\/ol>\n

    Trong b\u00e0i vi\u1ebft n\u00e0y, ch\u00fang ta c\u00f9ng nhau t\u00ecm hi\u1ec3u v\u1ec1 “T\u00ednh \u0111a h\u00ecnh (Polymorphism)”<\/strong><\/p>\n

    \u0110\u1ecbnh ngh\u0129a t\u00ednh \u0111a h\u00ecnh<\/h2>\n

    T\u00ednh \u0111a h\u00ecnh (<\/span>Polymorphism<\/span><\/i>) l\u00e0 m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n m\u1ed9t t\u00e1c v\u1ee5 theo nhi\u1ec1u c\u00e1ch kh\u00e1c nhau.<\/span><\/p>\n

    C\u00f4ng d\u1ee5ng c\u1ee7a t\u00ednh \u0111a h\u00ecnh<\/h2>\n

    K\u1ef9 thu\u1eadt \u0111a h\u00ecnh trong c\u00e1c ng\u00f4n ng\u1eef h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng gi\u00fap cho ch\u00fang ta gia t\u0103ng kh\u1ea3 n\u0103ng t\u00e1i s\u1eed d\u1ee5ng c\u00e1c \u0111o\u1ea1n m\u00e3 (code) \u0111\u01b0\u1ee3c vi\u1ebft m\u1ed9t c\u00e1ch t\u1ed5ng qu\u00e1t v\u00e0 c\u00f3 th\u1ec3 thay \u0111\u1ed5i c\u00e1c \u1ee9ng x\u1eed m\u1ed9t c\u00e1ch linh ho\u1ea1t t\u00f9y theo \u0111\u1ed1i t\u01b0\u1ee3ng.<\/span><\/p>\n

    C\u00e1ch s\u1eed d\u1ee5ng<\/h2>\n

    Trong l\u1eadp tr\u00ecnh s\u1ebd c\u00f3 2 k\u1ef9 thu\u1eadt \u0111\u1ec3 ch\u00fang ta c\u00f3 th\u1ec3 s\u1eed t\u00ednh \u0111a h\u00ecnh \u0111\u00f3 l\u00e0 <\/span>Override v\u00e0 Overloading.<\/span><\/p>\n

    Override (Ghi \u0111\u00e8)<\/h3>\n

    V\u00ed d\u1ee5:<\/span><\/i> Trong m\u1ed9t c\u00f4ng ty s\u1ebd c\u00f3 c\u00e1c <\/span>nh\u00e2n vi\u00ean<\/b> nh\u01b0 l\u1eadp tr\u00ecnh vi\u00ean, k\u1ebf to\u00e1n, nh\u00e2n vi\u00ean sale. M\u1ed7i <\/span>nh\u00e2n vi\u00ean<\/b> s\u1ebd c\u00f3 nh\u1eefng c\u00e1ch t\u00ednh l\u01b0\u01a1ng kh\u00e1c nhau.<\/span><\/p>\n

    D\u1ef1a tr\u00ean v\u00ed d\u1ee5, ch\u00fang ta s\u1ebd c\u00f3 class <\/span>Staff<\/b> \u0111\u1ea1i di\u1ec7n cho nh\u00e2n vi\u00ean v\u00e0 c\u00f3 thu\u1ed9c t\u00ednh <\/span>salary l\u00e0 m\u1ee9c l\u01b0\u01a1ng c\u01a1 b\u1ea3n<\/span>.<\/span><\/p>\n

    class Staff {\r\n   public int salary = 3;\r\n\r\n   public int countSalary() {\r\n       return this.salary;\r\n   }\r\n}<\/pre>\n
    Ti\u1ebfp theo ch\u00fang ta c\u00f3 <\/span>class<\/span><\/i> Developer<\/b> k\u1ebf th\u1eeba <\/span>class<\/span><\/i> Staff<\/b> v\u00e0 s\u1ebd ghi \u0111\u00e8 l\u00ean ph\u01b0\u01a1ng th\u1ee9c t\u00ednh l\u01b0\u01a1ng.<\/span><\/p>\n
    class Developer extends Staff {\r\n   public int rank = 4;\r\n  \r\n   @Override\r\n   public int countSalary() {\r\n       return this.salary * this.rank;\r\n   }\r\n}\r\n<\/pre>\n
    Nh\u00e2n vi\u00ean k\u1ebf to\u00e1n c\u00f3 th\u00eam tr\u1ee3 c\u1ea5p n\u00ean m\u1ed7i l\u1ea7n t\u00ednh l\u01b0\u01a1ng s\u1ebd \u0111\u01b0\u1ee3c c\u1ed9ng th\u00eam. N\u00ean ta c\u00f3 class <\/span>Accountant<\/b> kh\u00e1c v\u1edbi class <\/span>Developer.<\/b><\/p>\n
    class Accountant extends Staff {\r\n   public int rank = 3;\r\n   public int allowance = 3;\r\n\r\n   @Override\r\n   public int countSalary() {\r\n       return (this.salary * this.rank) + this.allowance;\r\n   }\r\n}<\/pre>\n
    <\/h3>\n
    Overloading (N\u1ea1p ch\u1ed3ng)<\/h3>\n
    Quay l\u1ea1i v\u00ed d\u1ee5 tr\u00ean, <\/span>trong qu\u00e1 tr\u00ecnh l\u00e0m vi\u1ec7c, s\u1ebd c\u00f3 l\u00fac l\u1eadp tr\u00ecnh vi\u00ean ph\u1ea3i t\u0103ng ca, v\u00ec v\u1eady kho\u1ea3n ti\u1ec1n t\u0103ng ca n\u00e0y s\u1ebd \u0111\u01b0\u1ee3c c\u1ed9ng th\u00eam v\u00e0o l\u01b0\u01a1ng. N\u1ebfu kh\u00f4ng t\u0103ng ca, th\u00ec l\u01b0\u01a1ng c\u1ee7a l\u1eadp tr\u00ecnh vi\u00ean s\u1ebd \u0111\u01b0\u1ee3c t\u00ednh theo c\u00f4ng th\u1ee9c nh\u01b0 b\u00ecnh th\u01b0\u1eddng.<\/span><\/p>\n
    class Developer extends Staff {\r\n   public int rank = 4;\r\n  \r\n   @Overload\r\n   public int countSalary() {\r\n       return this.salary * this.rank;\r\n   }\r\n\r\n   @Overload\r\n   public int countSalary(int overtime_money) {\r\n       return (this.salary * this.rank) + overtime_money;\r\n   }\r\n}<\/pre>\n
    public class Demo {\r\n \r\n    public static void main(String[] args) { \r\n        Developer developer = new Developer();\r\n \r\n        System.out.println(\"Basic salary:\" + developer.countSalary());\r\n        System.out.println(\"Salary with overtime money: \" + developer.countSalary(2));\r\n    }\r\n}<\/pre>\n
    Output<\/span><\/i>:<\/b><\/p>\n
    Basic salary: 12\r\nSalary with overtime money: 14\r\n<\/pre>\n
    Khi ch\u1ea1y ch\u01b0\u01a1ng tr\u00ecnh ch\u00fang ta s\u1ebd th\u1ea5y d\u1ef1a theo tham s\u1ed1 \u0111\u1ea7u v\u00e0o ch\u01b0\u01a1ng tr\u00ecnh s\u1ebd \u0111i\u1ec1u h\u01b0\u1edbng t\u1edbi ph\u01b0\u01a1ng th\u1ee9c t\u01b0\u01a1ng \u1ee9ng.<\/span><\/p>\n
    T\u00e0i li\u1ec7u tham kh\u1ea3o.<\/h2>\n
    https:\/\/en.wikipedia.org\/wiki\/Object-oriented_programming<\/span><\/a><\/p>\n
    https:\/\/stackify.com\/oop-concept-polymorphism\/<\/span><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
    T\u00ednh \u0111a h\u00ecnh l\u00e0 m\u1ed9t trong b\u1ed1n t\u00ednh ch\u1ea5t c\u01a1 b\u1ea3n c\u1ee7a l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng.<\/p>\n
    Trong b\u00e0i vi\u1ebft n\u00e0y ch\u00fang ta s\u1ebd c\u00f9ng t\u00ecm hi\u1ec3u v\u1ec1 t\u00ednh \u0111a h\u00ecnh nh\u00e9.<\/p>\n","protected":false},"author":16,"featured_media":661,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[34,22],"class_list":["post-660","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-technology","tag-marketenterprise-vietnam","tag-technical"],"_links":{"self":[{"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/posts\/660","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/comments?post=660"}],"version-history":[{"count":0,"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/posts\/660\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/media\/661"}],"wp:attachment":[{"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/media?parent=660"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/categories?post=660"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.marketenterprise.vn\/blog\/wp-json\/wp\/v2\/tags?post=660"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}