{"id":207890,"date":"2025-07-08T16:28:11","date_gmt":"2025-07-08T08:28:11","guid":{"rendered":"https:\/\/server.hk\/cnblog\/207890\/"},"modified":"2025-07-08T16:28:11","modified_gmt":"2025-07-08T08:28:11","slug":"golang-%e4%b8%ad%e7%9a%84%e7%a9%ba%e6%8e%a5%e5%8f%a3","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/207890\/","title":{"rendered":"Golang \u4e2d\u7684\u7a7a\u63a5\u53e3"},"content":{"rendered":"

<\/b> <\/p>\n

\u5f53\u524d\u4f4d\u7f6e\uff1a ><\/span> ><\/span> ><\/span> ><\/span> Golang \u4e2d\u7684\u7a7a\u63a5\u53e3<\/span><\/p>\n

\u6765\u6e90\uff1astackoverflow<\/span>
\n2024-04-26 14:27:41<\/span>
\n<\/i>0\u6d4f\u89c8<\/span>
\n<\/i>\u6536\u85cf<\/span> <\/p>\n

\u76ee\u524d\u4e0a\u5df2\u7ecf\u6709\u5f88\u591a\u5173\u4e8eGolang<\/span>\u7684\u6587\u7ae0\u4e86\uff0c\u81ea\u5df1\u5728\u521d\u6b21\u9605\u8bfb\u8fd9\u4e9b\u6587\u7ae0\u4e2d\uff0c\u4e5f\u89c1\u8bc6\u5230\u4e86\u5f88\u591a\u5b66\u4e60\u601d\u8def\uff1b\u90a3\u4e48\u672c\u6587\u300aGolang \u4e2d\u7684\u7a7a\u63a5\u53e3\u300b<\/span>\uff0c\u4e5f\u5e0c\u671b\u80fd\u5e2e\u52a9\u5230\u5927\u5bb6\uff0c\u5982\u679c\u9605\u8bfb\u5b8c\u540e\u771f\u7684\u5bf9\u4f60\u5b66\u4e60Golang<\/span>\u6709\u5e2e\u52a9\uff0c\u6b22\u8fce\u52a8\u52a8\u624b\u6307\uff0c\u8bc4\u8bba\u7559\u8a00\u5e76\u5206\u4eab~<\/p>\n

\u95ee\u9898\u5185\u5bb9
\n <\/p>\n

\u7f16\u8f91<\/strong>\uff1a\u8fd9\u4e0d\u662f<\/strong>\u5728 go \u4e2d\u4f7f\u7528\u63a5\u53e3\u7684\u6b63\u786e\u65b9\u6cd5\u3002\u8fd9\u4e2a\u95ee\u9898\u7684\u76ee\u7684\u662f\u8ba9\u6211\u4e86\u89e3\u7a7a\u63a5\u53e3\u5728 go \u4e2d\u662f\u5982\u4f55\u5de5\u4f5c\u7684\u3002<\/p>\n

\u5982\u679cgo\u4e2d\u7684\u6240\u6709\u7c7b\u578b\u90fd\u5b9e\u73b0\u4e86interface{}<\/code>\uff08\u7a7a\u63a5\u53e3\uff09\uff0c\u4e3a\u4ec0\u4e48\u6211\u65e0\u6cd5\u8bbf\u95eecat<\/code>\u548cdog<\/code>\u7ed3\u6784\u4e2d\u7684name<\/code>\u5b57\u6bb5\uff1f\u5982\u4f55\u901a\u8fc7\u51fd\u6570 sayhi() \u8bbf\u95ee\u6bcf\u4e2a\u7ed3\u6784\u4f53\u7684 name \u5b57\u6bb5\uff1f<\/p>\n

package main\n\nimport (\n    \"fmt\"\n)\n\nfunc sayHi(i interface{}) {\n\n    fmt.Println(i, \"says hello\")\n\n    \/\/ Not understanding this error message\n    fmt.Println(i.name) \/\/  i.name undefined (type interface {} is interface with no methods)\n} \n\ntype Dog struct{\n    name string\n}\ntype Cat struct{\n    name string\n}\n\nfunc main() {\n    d := Dog{\"Sparky\"}\n    c := Cat{\"Garfield\"}\n\n    sayHi(d) \/\/ {Sparky} says hello\n    sayHi(c) \/\/ {Garfield} says hello\n}<\/pre>\n
 <\/p>\n
\u89e3\u51b3\u65b9\u6848<\/h2>\n
 <\/p>\n
interface{}<\/code> \u662f\u65b9\u6cd5\u96c6\uff0c\u800c\u4e0d\u662f\u5b57\u6bb5\u96c6\u3002\u5982\u679c\u7c7b\u578b\u7684\u65b9\u6cd5\u5305\u542b\u8be5\u63a5\u53e3\u7684\u65b9\u6cd5\uff0c\u5219\u8be5\u7c7b\u578b\u5b9e\u73b0\u8be5\u63a5\u53e3\u3002\u7531\u4e8e\u7a7a\u63a5\u53e3\u6ca1\u6709\u4efb\u4f55\u65b9\u6cd5\uff0c\u56e0\u6b64\u6240\u6709\u7c7b\u578b\u90fd\u5b9e\u73b0\u5b83\u3002 <\/p>\n
\u5982\u679c\u9700\u8981\u8bbf\u95ee\u67d0\u4e2a\u5b57\u6bb5\uff0c\u5219\u5fc5\u987b\u83b7\u53d6\u539f\u59cb\u7c7b\u578b\uff1a<\/p>\n
name, ok:=i.(dog).name<\/pre>\n
\u5982\u679c i<\/code> \u662f dog<\/code>\uff0c\u8fd9\u5c06\u6062\u590d\u540d\u79f0\u3002 <\/p>\n
\u6216\u8005\uff0c\u4e3a dog<\/code> \u548c cat<\/code> \u5b9e\u73b0 getname()<\/code> \u51fd\u6570\uff0c\u7136\u540e\u5b83\u4eec\u90fd\u5c06\u5b9e\u73b0\u4ee5\u4e0b\u63a5\u53e3\uff1a<\/p>\n
type namedtype interface {\n   getname() string\n}<\/pre>\n
\u7136\u540e\u4f60\u53ef\u4ee5\u5c06\u4f60\u7684\u51fd\u6570\u91cd\u5199\u4e3a\uff1a<\/p>\n
func sayhi(i namedtype) {\n   fmt.println(i.getname()) \n}<\/pre>\n
\u60a8\u4e0d\u80fd\u8fd9\u6837\u505a\uff0c\u56e0\u4e3a\u63a5\u53e3\u503c\u4e0d\u4f1a\u8fd9\u6837\u505a\u3002<\/p>\n
\u63a5\u53e3\u503c\u7684\u4f5c\u7528\u662f\u4ec0\u4e48\u2014\u2014\u65e0\u8bba\u63a5\u53e3\u7c7b\u578b\u672c\u8eab\u5982\u4f55\uff1b<\/em>\u63a5\u53e3\u7c7b\u578b\u662f\u5426\u4e3a\u7a7a\u5e76\u4e0d\u91cd\u8981\uff0c\u91cd\u8981\u7684\u662f\u5b83\u4eec\u5305\u542b\u4e24\u4ef6\u4e8b\uff1a<\/p>\n
    \n
  • \u67d0\u4e2a\u503c\u7684\u5177\u4f53\u7c7b\u578b\uff08\u6216\u65e0\u7c7b\u578b\uff09\uff1b\u548c<\/li>\n
  • \u8be5\u5177\u4f53\u7c7b\u578b\u7684\u503c\uff08\u6216\u65e0\u503c\uff09\u3002<\/li>\n<\/ul>\n
    \u56e0\u6b64\uff0c\u5982\u679c\u67d0\u4e2a\u53d8\u91cf v<\/code> \u6216\u8868\u8fbe\u5f0f e<\/code> \u7684\u7c7b\u578b\u4e3a i<\/code>\uff0c\u5176\u4e2d i<\/code> \u662f\u63a5\u53e3\u7c7b\u578b\uff0c\u90a3\u4e48\u60a8\u53ef\u4ee5\u4f7f\u7528\u67d0\u79cd\u8bed\u6cd5\u68c0\u67e5\u8fd9\u4e24\u4e2a\u201c\u5b57\u6bb5\u201d\u4e2d\u7684\u4e00\u4e2a\u6216\u4e24\u4e2a\u3002\u5b83\u4eec\u4e0d\u662f struct<\/code> \u5b57\u6bb5\uff0c\u56e0\u6b64\u60a8\u4e0d\u80fd\u53ea\u4f7f\u7528 v.type<\/code>\uff0c\u4f46\u60a8\u53ef\u4ee5<\/em>\u6267\u884c\u4ee5\u4e0b\u64cd\u4f5c\uff1a<\/p>\n
    switch v.(type) {\ncase int: \/\/ the value in v has type int\ncase *float64: \/\/ the value in v has type float64\n\/\/ etc\n}<\/pre>\n
    switch<\/code> \u4e2d\u7684 .(type)<\/code> \u8868\u793a\u8ba9\u6211\u770b\u770b\u7c7b\u578b\u5b57\u6bb5<\/em>\u3002<\/p>\n
    \u83b7\u53d6\u5b9e\u9645\u503c<\/em>\u6bd4\u8f83\u56f0\u96be\uff0c\u56e0\u4e3a go \u6216\u591a\u6216\u5c11\u8981\u6c42\u60a8\u9996\u5148\u68c0\u67e5\u7c7b\u578b\u3002\u5728\u60a8\u7684\u60c5\u51b5\u4e0b\uff0c\u60a8\u77e5\u9053 i<\/code> \u6301\u6709 dog<\/code> \u6216 cat<\/code>\uff0c\u56e0\u6b64\u60a8\u53ef\u4ee5\u7f16\u5199\uff1a<\/p>\n
    var name string\nswitch i.(type) {\ncase dog: name = i.(dog).name\ncase cat: name = i.(cat).name\ndefault: panic(\"whatever 'i' is, it is not a dog or cat\")\n}\nfmt.println(name)<\/pre>\n
    \u8fd9\u76f8\u5f53\u7b28\u62d9\uff0c\u6709\u5f88\u591a\u65b9\u6cd5\u53ef\u4ee5\u8ba9\u5b83\u53d8\u5f97\u4e0d\u90a3\u4e48\u7b28\u62d9\uff0c\u4f46\u8fd9\u59cb\u7ec8\u662f\u7b2c\u4e00\u6b65\uff1a\u5f04\u6e05\u695a\u7c7b\u578b\u662f\u4ec0\u4e48<\/em>\u3002<\/p>\n
    \u55ef\uff0c\u6709\u65f6\u7b2c\u4e00\u6b65\u4e4b\u524d\u8fd8\u6709\u4e00\u4e2a\u6b65\u9aa4\uff1a\u5f04\u6e05\u695a\u53d8\u91cf\u4e2d\u662f\u5426\u6709\u4efb\u4f55\u5185\u5bb9\u3002<\/em>\u4f60\u53ef\u4ee5\u8fd9\u6837\u505a\uff1a<\/p>\n
    if i == nil {\n    ...\n}<\/pre>\n
    \u4f46\u662f\u8bf7\u6ce8\u610f\uff0c\u5982\u679c i<\/code> \u4e2d\u6709\u4e00\u4e9b\u7c7b\u578b<\/em>\u503c\uff0c\u5e76\u4e14\u8be5\u7c7b\u578b\u53ef\u4ee5\u4fdd\u5b58 nil \u6307\u9488\uff0c\u5219 i<\/code> \u7684\u503c<\/em>\u90e8\u5206\u53ef\u4ee5\u4e3a nil\uff0c\u4f46 i == nil<\/code> \u5c06\u4e3a false\u3002\u8fd9\u662f\u56e0\u4e3a i<\/code> \u4e2d\u786e\u5b9e<\/em>\u6709\u4e00\u4e2a\u7c7b\u578b<\/em>\u3002<\/p>\n
    var i interface{}\nvar p *int\nif i == nil {\n    fmt.println(\"i is initially nil\")\n}\nif p == nil {\n    fmt.println(\"p is nil\")\n}\ni = p\nif i != nil {\n    fmt.printf(\"i is now not nil, even though i.(*int) is %v\\n\", i.(*int))\n}<\/pre>\n
    \uff08\u5728 \u4e0a\u5c1d\u8bd5\u6b64\u64cd\u4f5c\uff09\u3002<\/p>\n
    \u8fd9\u901a\u5e38\u4e0d\u662f\u4f7f\u7528 interface<\/code> \u7684\u6b63\u786e\u65b9\u6cd5<\/h3>\n
    \u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff08\u4e5f\u6709\u4f8b\u5916\uff09\u6211\u4eec\u751a\u81f3\u4e0d\u4f1a\u5c1d\u8bd5<\/em>\u67e5\u770b\u67d0\u4e9b\u63a5\u53e3\u7684\u7c7b\u578b\u3002\u76f8\u53cd\uff0c\u6211\u4eec\u5b9a\u4e49\u4e00\u4e2a\u63a5\u53e3\uff0c\u63d0\u4f9b\u65b9\u6cd5<\/em>\uff08\u6211\u4eec\u53ef\u4ee5\u8c03\u7528\u7684\u51fd\u6570\uff09\u6765\u5b8c\u6210\u6211\u4eec\u9700\u8981\u5b8c\u6210\u7684\u4e8b\u60c5\u3002\u8bf7\u53c2\u9605 \uff0c\u5176\u4e2d\u63a5\u53e3\u7c7b\u578b\u6709\u4e00\u4e2a getname<\/code> \u65b9\u6cd5\u3002\u7136\u540e\uff0c\u6211\u4eec\u4e0d\u518d\u8bd5\u56fe\u627e\u51fa\u67d0\u4eba\u7ed9\u6211\u4eec\u7684\u6709\u9650\u7c7b\u578b\u4e2d\u7684\u54ea\u4e00\u4e2a\uff0c\u800c\u662f\u8bf4\uff1a<\/p>\n
    name := i.getName()<\/pre>\n
    \u5bf9\u5e95\u5c42\u5177\u4f53\u503c\u8c03\u7528 getname<\/code> \u65b9\u6cd5<\/em>\u3002\u5982\u679c i<\/code> \u6301\u6709 dog<\/code>\uff0c\u5219\u8c03\u7528 func (dog) getname() string<\/code>\uff0c\u60a8\u9700\u8981\u5b9a\u4e49\u5b83\u3002\u5982\u679c i<\/code> \u6301\u6709 cat<\/code>\uff0c\u5219\u5b83\u8c03\u7528 func (cat) getname() string<\/code>\u3002\u5982\u679c\u60a8\u51b3\u5b9a\u5411\u96c6\u5408\u4e2d\u6dfb\u52a0\u540d\u4e3a bird<\/code> \u7684\u7c7b\u578b\uff0c\u5219\u53ef\u4ee5\u5b9a\u4e49 func (bird) getname() string<\/code> \u7b49\u3002<\/p>\n
    \uff08\u901a\u5e38\uff0c\u8fd9\u4e9b\u65b9\u6cd5\u4e5f\u4f1a\u5bfc\u51fa<\/em>\uff1agetname<\/code>\uff0c\u800c\u4e0d\u662f getname<\/code>\u3002\uff09<\/p>\n
    \u4ee5\u4e0a\u5c31\u662f\u300aGolang \u4e2d\u7684\u7a7a\u63a5\u53e3\u300b\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u5173\u4e8e\u7684\u8d44\u6599\u8bf7\u5173\u6ce8\u516c\u4f17\u53f7\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
    \u5f53\u524d\u4f4d\u7f6e\uff1a > > ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-207890","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/207890","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=207890"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/207890\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=207890"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=207890"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=207890"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}