{"id":1955,"date":"2024-08-03T14:39:11","date_gmt":"2024-08-03T06:39:11","guid":{"rendered":"https:\/\/blog.xiunian.wang\/?p=1955"},"modified":"2024-08-26T14:19:14","modified_gmt":"2024-08-26T06:19:14","slug":"%e8%81%8a%e8%81%8akotlin%e4%b8%ad%e7%9a%84%e7%bb%a7%e6%89%bf%e5%92%8c%e7%bb%84%e5%90%88","status":"publish","type":"post","link":"https:\/\/blog.xiunian.wang\/?p=1955","title":{"rendered":"\u804a\u804aKotlin\u4e2d\u7684\u7ee7\u627f\u548c\u7ec4\u5408"},"content":{"rendered":"\n

\u5728\u4f17\u591a\u4ecb\u7ecd\u8f6f\u4ef6\u67b6\u6784\u7684\u4e66\u7c4d\u4e2d\uff0c\u7279\u522b\u662f OOP \u8bed\u8a00\u4e3a\u57fa\u51c6\u7684\u8bdd\uff0c\u4f60\u4e00\u5b9a\u542c\u8bf4\u8fc7\u4e00\u53e5\u8bdd\u201c\u7ec4\u5408\u4f18\u4e8e\u7ee7\u627f\u201d \u3010Favor composition over inheritance\u3011<\/p>\n\n\n\n

\u4e3a\u4ec0\u4e48\u8fd9\u4e48\u8bf4\uff1f \u6211\u4eec\u6765\u770b\u4e00\u4e2a\u4f8b\u5b50\u3002\u7ee7\u627f\u975e\u5e38\u597d\u7406\u89e3\uff0c\u6211\u4eec\u9700\u8981\u521b\u5efa\u4e00\u53ea\u9e21\uff0c\u4e00\u53ea\u9e2d\uff0c\u6211\u4eec\u5f88\u5bb9\u6613\u62bd\u8c61\u51fa\u201c\u9e1f\u7c7b\u201d\u8fd9\u4e2a\u7236\u7c7b\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n\n\n\n\n

open class Bird {\n    val haveWing = true\n    fun fly() {\n        println(\"I can fly\")\n    }\n}\n\nclass Duck : Bird() {\n    fun swim() {\n        println(\"I can swim\")\n    }\n}\n\nclass Chicken : Bird() {\n    fun whoop() {\n        println(\"go go go\")\n    }\n}<\/pre>\n\n\n\n
\u540c\u65f6\u517c\u987e\u4e86 \u9e2d\u5b50\u4f1a\u6e38\u6cf3\uff0c\u9e21\u4f1a\u6253\u9e23\u8fd9\u79cd\u7279\u6027\u3002\u975e\u5e38\u7b80\u5355\u597d\u7406\u89e3\u3002<\/p>\n\n\n\n
\u4f46\u73b0\u5b9e\u60c5\u51b5\uff08\u9700\u6c42\uff09\u603b\u662f\u5728\u6539\u53d8\u3002\u67d0\u4e00\u5929\uff0c\u7cfb\u7edf\u4e2d\u51fa\u73b0\u4e86\u4e00\u4e0d\u4f1a\u98de\u7684\u9e1f- \u9e35\u9e1f\uff0c\u867d\u7136\u4e5f\u662f\u9e1f\u7c7b\uff0c\u6709\u7fc5\u8180\uff0c\u4f46\u662f\u5e76\u4e0d\u4f1a\u98de\uff0c\u56e0\u6b64\u5c06\u98de\u884c\u7684\u52a8\u4f5c\u4e0b\u653e\u5230\u5177\u4f53\u7684\u5b50\u7c7b\u4e2d\u53bb\uff0c\u8fd9\u65f6\u5019\u9700\u8981\u4fee\u6539\u6240\u6709<\/strong>\u73b0\u6709\u7684\u5b50\u7c7b\u4e86\u3002<\/p>\n\n\n\n
open class Bird {\n    val haveWing = true\n}\n\nclass Duck : Bird() {\n    fun swim() {\n        println(\"I can swim\")\n    }\n    fun fly() {\n        println(\"I can fly\")\n    }\n}\n\nclass Chicken : Bird() {\n    fun whoop() {\n        println(\"go go go\")\n    }\n    fun fly() {\n        println(\"I can fly\")\n    }\n}\nclass Ostrich : Bird() {\n\/\/\u6211\u4e0d\u4f1a\u98de\n}<\/pre>\n\n\n\n
\u867d\u7136\u529f\u80fd\u662f OK \u4e86\uff0c\u8fd9\u6837\u5982\u679c\u540e\u7eed\u9700\u8981\u5bf9 fly \u8fdb\u884c\u4e00\u4e9b\u8c03\u6574\u7684\u8bdd\uff0c\u6240\u6709\u5177\u4f53\u7c7b\u7684fly \u90fd\u8981\u8c03\u6574\uff0c\u5bf9\u4e8e\u4e00\u4e9b\u5386\u53f2\u4ee3\u7801\u6216\u8005library\uff0c\u6839\u672c\u65e0\u6cd5\u968f\u4fbf\u66f4\u6539\u3002\u518d\u4e3e\u4e2a\u4f8b\u5b50\uff0c\u7cfb\u7edf\u4e2d\u67d0\u5929\u5f15\u5165\u4e86\u72d7\uff0c\u8fd9\u53ea\u72d7\u4e5f\u4f1awhoop\uff0c\u6211\u4eec\u65b0\u589e\u4e00\u4e2a Dog\u7c7b\u3002 Animal\u4f5c\u4e3a\u6240\u6709\u5b50\u7c7b\u7684\u5171\u540c\u7236\u7c7b\uff0c\u5177\u5907\u5982\u4e0b\u7ee7\u627f\u5173\u7cfb\u3002<\/p>\n\n\n\n
open class Animal{\n\n}\nopen class Bird : Animal() {\n    val haveWing = true\n}\n\nclass Duck : Bird() {\n    fun swim() {\n        println(\"I can swim\")\n    }\n\n    fun fly() {\n        println(\"I can fly\")\n    }\n}\n\nclass Chicken : Bird() {\n    fun whoop() {\n        println(\"go go go\")\n    }\n\n    fun fly() {\n        println(\"I can fly\")\n    }\n}\n\nclass Dog : Animal() {\n    fun whoop() {\n        println(\"wang wang wang\")\n    }\n}<\/pre>\n\n\n\n
\u6211\u4eec\u53d1\u73b0\uff0cwhoop \u6ca1\u529e\u6cd5\u653e\u5230 chicken \u548c dog \u7684\u5171\u540c\u7236\u7c7b Animal \u4e2d\u53bb\u5b9e\u73b0\u590d\u7528\uff0c\u56e0\u4e3a Duck \u7b49\u5176\u4ed6\u9e1f\u7c7b\u548c\u52a8\u7269\u5e76\u4e0d\u80fd\u5904\u7406\u8fd9\u79cd\u884c\u4e3a\u3002\u800c\u5f88\u591a oop \u7f16\u7a0b\u8bed\u8a00\u4e2d\uff0c\u6bd4\u5982 Java \u548c C# \u4e2d\u4e5f\u4e0d\u652f\u6301\u591a\u7ee7\u627f\u3002 \u56e0\u6b64\uff0c\u8981\u60f3\u5b9e\u73b0\u590d\u7528\u903b\u8f91\uff0c\u6211\u4eec\u5c31\u8981\u4f7f\u7528\u7ec4\u5408\u6a21\u5f0f composition.<\/p>\n\n\n\n
\u9996\u5148\uff0c\u6211\u4eec\u5b9a\u4e49\u98de\u884c\u63a5\u53e3 IFly, \u540c\u65f6\u5199\u4e00\u4e2a\u5b9e\u73b0\uff08\u4e5f\u5c31\u662f\u6211\u4eec\u8981\u5c06duck \u548c chicken \u7684fly \u884c\u4e3a\u7684\u5177\u4f53\u5b9e\u73b0\u62bd\u79bb\u5230\u4e00\u4e2a\u5730\u65b9\u6765\u5b9e\u73b0\uff0c\u4ee5\u4fbf\u590d\u7528\u4ee3\u7801\uff0c\u4e00\u6b21\u66f4\u6539\uff0c\u5168\u90e8\u751f\u6548<\/strong>\uff09\u3002<\/p>\n\n\n\n
interface IFly {\n    fun fly()\n}\nclass FlyBehaviour : IFly {\n    override fun fly() {\n        println(\"I can fly\")\n    }\n}<\/pre>\n\n\n\n
\u7136\u540e\u8ba9duck \u548c chicken \u5177\u5907\u8fd9\u79cd\u884c\u4e3a\uff0c\u9996\u5148\u53ef\u4ee5\u8ba9\u5b83\u4eec\u90fd\u5b9e\u73b0 IFly \u63a5\u53e3\uff0c\u5f53\u7136\u81ea\u5df1\u4e0d\u80fd\u771f\u6b63\u5904\u7406\uff0c\u4ea4\u7ed9\u4e0a\u9762\u7684\u5b9e\u73b0\u6765\u771f\u6b63\u5904\u7406\uff0c\u4fee\u6539\u5982\u4e0b\u3002<\/p>\n\n\n\n
class Duck(val flyBehaviour: IFly) : Bird(),IFly {\n    fun swim() {\n        println(\"I can swim\")\n    }\n\n    override fun fly() {\n        flyBehaviour.fly()\n    }\n}\n\nclass Chicken(val flyBehaviour: IFly) : Bird(), IFly {\n    fun whoop() {\n        println(\"go go go\")\n    }\n\n    override fun fly() {\n        flyBehaviour.fly()\n    }\n}<\/pre>\n\n\n\n
\u8fd9\u6837\u6211\u4eec\u53ef\u4ee5\u8ba9\u4e24\u8005\u4ece is-A \uff08\u7ee7\u627f\uff09\u53d8\u4e3a\u4e86has-A\uff08\u7ec4\u5408\uff0c\u62e5\u6709\uff09\uff0c\u6211\u4eec\u5728\u8fd0\u884c\u65f6\uff0c\u53ef\u4ee5\u901a\u8fc7\u4f20\u53c2\u6570\u6216\u8005\u5176\u4ed6 \u4f9d\u8d56\u6ce8\u5165\u6765\u5b9e\u4f8b\u5316\u5177\u4f53\u7684\u5b9e\u73b0\u3002\u5168\u90e8\u4ee3\u7801\u5982\u4e0b<\/p>\n\n\n\n
fun main() {\n    val dog= Dog()\n    dog.whoop()\n    val flyBehaviour=FlyBehaviour()\n    val duck = Duck(flyBehaviour)\n    duck.fly()\n    duck.swim()\n    val chicken= Chicken(flyBehaviour)\n    chicken.fly()\n    chicken.whoop()\n}\ninterface IFly {\n    fun fly()\n}\nopen class Animal{\n\n}\nopen class Bird : Animal() {\n    val haveWing = true\n}\n\nclass Duck(val flyBehaviour: IFly) : Bird(),IFly {\n    fun swim() {\n        println(\"I can swim\")\n    }\n\n    override fun fly() {\n        flyBehaviour.fly()\n    }\n}\n\nclass Chicken(val flyBehaviour: IFly) : Bird(), IFly {\n    fun whoop() {\n        println(\"go go go\")\n    }\n\n    override fun fly() {\n        flyBehaviour.fly()\n    }\n}\nclass FlyBehaviour : IFly {\n    override fun fly() {\n        println(\"I can fly\")\n    }\n}\nclass Dog : Animal() {\n    fun whoop() {\n        println(\"wang wang wang\")\n    }\n}<\/pre>\n\n\n\n
\u8fd9\u6837\u6211\u4eec\u9700\u8981\u4fee\u6539\u5b9e\u73b0\uff0c\u53ef\u4ee5\u53ea\u4fee\u6539FlyBehaviour\u7684\u5b9e\u73b0\u5185\u5bb9\u3002\u540c\u65f6\u5982\u679c\u9700\u8981\u7684\u8bdd\uff0c\u4e5f\u53ef\u4ee5\u4e3a Chicken \u548c Duck\u4f20\u5165\u4e0d\u540c\u7684flyBehaviour<\/code>  \u3002<\/p>\n\n\n\n
\u4f46\u662f\u6211\u4eec\u8fd8\u662f\u53d1\u73b0\uff0c\u8fd9\u6837\u4e0a\u9762\u7684\u6837\u677f\u4ee3\u7801\u8fd8\u662f\u6709\u70b9\u591a\u3002\u6bd4\u5982 Chicken \u548c Duck \u9700\u8981\u5b9e\u73b0 IFly\u63a5\u53e3\u7684\u6bcf\u4e00\u4e2a\u65b9\u6cd5\uff0c\u7136\u540e\u518d\u8c03\u7528 flyBehaviour\u7684\u5177\u4f53\u5b9e\u73b0\uff0c\u5982\u679c IFly \u6709\u5f88\u591a\u901a\u7528\u80fd\u529b\u7684\u8bdd\uff0c\u5c31\u975e\u5e38\u5570\u55e6\u3002\u597d\u5728 Kotlin \u7ed9\u6211\u4eec\u63d0\u4f9b\u4e86\u4e00\u4e2a\u4ee3\u7406\u8bed\u6cd5\u901a\u8fc7 by <\/code> \u6211\u4eec\u53ef\u4ee5\u4e00\u884c\u4ee3\u7801\u4e0d\u7528\u5199 \u76f4\u63a5\u5c06\u9700\u8981\u7684\u80fd\u529b\u4ee3\u7406\u8fc7\u53bb\uff0c\u6700\u7ec8\u4fee\u6539\u540e\u7684 Chicken \u548c Duck \u5982\u4e0b<\/p>\n\n\n\n
class Duck(val flyBehaviour: IFly) : Bird(), IFly by flyBehaviour {\n    fun swim() {\n        println(\"I can swim\")\n    }\n}\n\nclass Chicken(val flyBehaviour: IFly) : Bird(), IFly by flyBehaviour {\n    fun whoop() {\n        println(\"go go go\")\n    }\n}<\/pre>\n\n\n\n
\u662f\u4e0d\u662f\u770b\u4e0a\u53bb\uff0c\u50cf\u662f\u53c8\u7ee7\u627f\u53c8\u7ec4\u5408\u7684\u98ce\u683c\uff1f  \u53ef\u62d3\u5c55\u6027\u4e5f\u5927\u5927\u63d0\u9ad8\u4e86\u3002\u4f46\u662f\u8fd9\u91cc\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u7ee7\u627f,\u5728\u7236\u7c7b\u7684\u5b9e\u73b0\u4e2d\u53ef\u4ee5\u8c03\u7528 \u5b50\u7c7b\u7684\u65b9\u6cd5\uff0c\u7ec4\u5408\u7684\u5b9e\u73b0\u5219\u65e0\u6cd5\u76f4\u63a5\u8bbf\u95ee\u5230\u5bf9\u5e94owner\u7684\u5177\u4f53\u65b9\u6cd5\u3002 \u6211\u4eec\u5047\u8bbe\u5728 fly \u7684\u5b9e\u73b0\u8fc7\u7a0b\u4e2d\uff0c\u4e00\u4e9b\u9e1f\u5185\u9700\u8981\u52a9\u8dd1\u4e00\u6bb5\u65f6\u95f4\u3002\u5219\u98de\u884c\u63a5\u53e3 IFly\u4e2d\u53ef\u4ee5\u518d\u58f0\u660e\u4e00\u4e2a run \u65b9\u6cd5\u3002\u90a3\u4e48\u5728 fly \u65b9\u6cd5\u4e2d\u8c03\u7528\uff0c\u4e0d\u4f1a\u8c03\u7528\u5230\u5177\u4f53\u88ab\u4ee3\u7406\u8005\u7684 run \u65b9\u6cd5\u4e2d\uff0c\u4ee3\u7801\u5c55\u793a\u5982\u4e0b<\/p>\n\n\n\n
fun main() {\n    val flyBehaviour = FlyBehaviour()\n    val duck= Duck(flyBehaviour)\n    duck.fly()\n}\ninterface IFly {\n    fun fly()\n    fun run()\n}\n\nclass Duck(val flyBehaviour: IFly) : Bird(), IFly by flyBehaviour {\n    fun swim() {\n        println(\"I can swim\")\n    }\n\n    override fun run() {\n        println(\"duck is running\")\/\/\u8fd9\u91cc\u65e0\u6cd5\u901a\u8fc7 \u8c03\u7528Duck\u7684 fly \u6765 \u6267\u884c run\n    }\n}\nclass FlyBehaviour : IFly {\n    override fun fly() {\n        run()\/\/\u8d77\u98de\u524d\u5148\u52a9\u8dd1\u4e00\u6bb5\n        println(\"I can fly\")\n    }\n\n    override fun run() {\n        println(\"call in FlyBehaviour \")\/\/fly\u8c03\u7528\u7684\u662f\u8fd9\u4e2a\u65b9\u6cd5\n    }\n}\n\nopen class Animal{\n\n}\nopen class Bird : Animal() {\n    val haveWing = true\n}\n<\/pre>\n\n\n\n
\u8f93\u51fa\u5982\u4e0b<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\u6700\u540e\uff0cFavor composition over inheritance \u5e76\u4e0d\u662f\u94c1\u5f8b\uff0c\u901a\u8fc7\u7ee7\u627f\uff0c\u6211\u4eec\u53ef\u4ee5\u5f88\u76f4\u89c2\u7684\u590d\u7528\u4ee3\u7801\u3002\u901a\u8fc7\u7ec4\u5408\u6211\u4eec\u9700\u8981\u6784\u9020\u66f4\u591a\u5bf9\u8c61\u4ee5\u53ca\u7ef4\u62a4\u8fd9\u4e9b\u5bf9\u8c61\uff0c\u589e\u52a0\u4e86\u590d\u6742\u5ea6\uff0c\u540c\u65f6\u8fd8\u6709\u6837\u677f\u4ee3\u7801\uff08\u867d\u7136 Kotlin \u4ee3\u7406\u5e2e\u6211\u4eec\u51cf\u5c11\u4e86\u5f88\u591a\uff09\u3002 \u56e0\u6b64\uff0c\u4f7f\u7528\u7ee7\u627f\u8fd8\u662f\u7ec4\u5408\u6a21\u5f0f\uff0c\u5e94\u8be5\u8981\u5145\u5206\u8003\u8651\u5b9e\u9645\u573a\u666f\uff0c\u8fd9\u770b\u8d77\u6765\u50cf\u4e00\u53e5\u5e9f\u8bdd\uff0c\u8bf4\u70b9\u66f4\u5177\u4f53\u7684\uff0c\u6bd4\u5982\u4e0a\u9762\u4f8b\u5b50\u6211\u5c06 fly \u7406\u6240\u5f53\u7136\u7684\u5f53\u505a\u4e86 bird \u7684\u80fd\u529b\uff0c\u5b9e\u9645\u4e0a\u662f\u8003\u8651\u4e0d\u5468\uff0c\u4ee5\u8fd9\u4e2a\u4e3a\u4f8b\u5b50\uff0c\u5982\u679c\u4f60\u5341\u5206\u7b03\u5b9a\u5b50\u7c7b\u4e00\u5b9a\u5177\u5907\u8fd9\u6837\u7684\u80fd\u529b\uff0c\u624d\u8003\u8651\u7ee7\u627f\u5173\u7cfb\u3002<\/p>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5728\u4f17\u591a\u4ecb\u7ecd\u8f6f\u4ef6\u67b6\u6784\u7684\u4e66\u7c4d\u4e2d\uff0c\u7279\u522b\u662f OOP \u8bed\u8a00\u4e3a\u57fa\u51c6\u7684\u8bdd\uff0c\u4f60\u4e00\u5b9a\u542c\u8bf4\u8fc7\u4e00\u53e5\u8bdd\u201c\u7ec4\u5408\u4f18\u4e8e\u7ee7\u627f\u201d \u3010Favor composition over inheritance\u3011 \u4e3a\u4ec0\u4e48\u8fd9\u4e48\u8bf4\uff1f \u6211\u4eec\u6765\u770b\u4e00\u4e2a\u4f8b\u5b50\u3002\u7ee7\u627f\u975e\u5e38\u597d\u7406\u89e3\uff0c\u6211\u4eec\u9700\u8981\u521b\u5efa\u4e00\u53ea\u9e21\uff0c\u4e00\u53ea\u9e2d\uff0c\u6211\u4eec\u5f88\u5bb9\u6613\u62bd\u8c61\u51fa\u201c\u9e1f\u7c7b\u201d\u8fd9\u4e2a\u7236\u7c7b\u3002\u5982\u4e0b\uff1a<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,8],"tags":[13,28,26],"_links":{"self":[{"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=\/wp\/v2\/posts\/1955"}],"collection":[{"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1955"}],"version-history":[{"count":10,"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=\/wp\/v2\/posts\/1955\/revisions"}],"predecessor-version":[{"id":1970,"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=\/wp\/v2\/posts\/1955\/revisions\/1970"}],"wp:attachment":[{"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1955"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1955"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.xiunian.wang\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1955"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}