{"id":10021443,"date":"2026-09-07T20:01:17","date_gmt":"2026-09-07T12:01:17","guid":{"rendered":"https:\/\/itmax.cn\/?p=10021443"},"modified":"2026-09-07T20:01:17","modified_gmt":"2026-09-07T12:01:17","slug":"%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3-go-%e7%9a%84-struct","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10021443","title":{"rendered":"\u6df1\u5165\u7406\u89e3 Go \u7684 struct{}"},"content":{"rendered":"

\u5728 Go<\/code> \u4ee3\u7801\u4e2d\uff0c\u6211\u4eec\u7ecf\u5e38\u770b\u5230\u4e0b\u9762\u4e24\u79cd\u5199\u6cd5\uff1a<\/p>\n

set := make(map[string]struct{})\ndone := make(chan struct{})<\/code><\/pre>\n
\u5b83\u4eec\u90fd\u4f7f\u7528\u4e86\u7a7a\u7ed3\u6784\u4f53 struct{}<\/code>\u3002\u6211\u4eec\u901a\u5e38\u8bf4\uff1a<\/p>\n
struct{} \u4e0d\u5360\u7528\u4efb\u4f55\u7a7a\u95f4\u3002<\/p><\/blockquote>\n
\u66f4\u51c6\u786e\u5730\u8bf4\uff0cstruct{}<\/code> \u662f\u4e00\u4e2a\u5927\u5c0f\u4e3a 0\u3001\u4e0d\u643a\u5e26\u4efb\u4f55\u72b6\u6001\u7684\u5408\u6cd5\u7c7b\u578b\u3002\u4f46\u5305\u542b\u5b83\u7684\u6307\u9488\u3001\u63a5\u53e3\u3001\u5207\u7247\u3001map \u548c channel \u4ecd\u7136\u53ef\u80fd\u4ea7\u751f\u5185\u5b58\u4e0e\u8fd0\u884c\u65f6\u5f00\u9500\u3002<\/p>\n
1. struct{}<\/code> \u4e3a\u4ec0\u4e48\u662f\u96f6\u5927\u5c0f<\/h3>\n
struct{}<\/code> \u662f\u4e00\u4e2a\u6ca1\u6709\u4efb\u4f55\u5b57\u6bb5\u7684\u533f\u540d\u7ed3\u6784\u4f53\uff1a<\/p>\n
var value struct{}<\/p><\/blockquote>\n
\u7531\u4e8e\u6ca1\u6709\u5b57\u6bb5\u9700\u8981\u5b58\u50a8\uff0c\u5b83\u7684\u5927\u5c0f\u4e3a 0\uff1a<\/p>\n
package main\n\nimport (\n    "fmt"\n    "unsafe"\n)\n\nfunc main() {\n    fmt.Println(unsafe.Sizeof(struct{}{})) \/\/ 0\n}<\/code><\/pre>\n
\u8fd8\u53ef\u4ee5\u7ed9\u7a7a\u7ed3\u6784\u4f53\u5b9a\u4e49\u4e00\u4e2a\u5177\u540d\u7c7b\u578b\uff1a<\/p>\n
type Empty struct{}<\/p><\/blockquote>\n
\u5b83\u5177\u6709\u4ee5\u4e0b\u7279\u70b9\uff1a<\/p>\n
    \n
  • \u4e0d\u5305\u542b\u4efb\u4f55\u5b57\u6bb5<\/li>\n
  • \u96f6\u503c\u4e3a struct{}{}<\/code><\/li>\n
  • \u5927\u5c0f\u4e3a 0<\/li>\n
  • \u5c5e\u4e8e\u53ef\u6bd4\u8f83\u7c7b\u578b<\/li>\n
  • \u6240\u6709 struct{} \u503c\u90fd\u76f8\u7b49<\/li>\n
  • \u53ef\u4ee5\u5b9a\u4e49\u65b9\u6cd5<\/li>\n<\/ul>\n
    a := struct{}{}\nb := struct{}{}\n\nfmt.Println(a == b) \/\/ true<\/code><\/pre>\n
    \u56e0\u4e3a\u7ed3\u6784\u4f53\u6309\u7167\u5b57\u6bb5\u9010\u4e00\u6bd4\u8f83\uff0c\u800c\u7a7a\u7ed3\u6784\u4f53\u6ca1\u6709\u4efb\u4f55\u5b57\u6bb5\uff0c\u6240\u4ee5\u4e0d\u5b58\u5728\u4e0d\u76f8\u7b49\u7684\u60c5\u51b5\u3002<\/p>\n
    2. \u96f6\u5927\u5c0f\u4e0d\u7b49\u4e8e\u96f6\u6210\u672c<\/h3>\n
    \u7a7a\u7ed3\u6784\u4f53\u672c\u8eab\u4e0d\u5360\u7a7a\u95f4\uff0c\u4f46\u627f\u8f7d\u5b83\u7684\u6570\u636e\u7ed3\u6784\u4ecd\u7136\u6709\u6210\u672c\uff1a<\/p>\n
    var value struct{}\nvar pointer *struct{}\nvar iface any = struct{}{}\nvar slice []struct{}\nvar channel chan struct{}\nvar mapping map[string]struct{}<\/code><\/pre>\n
    \u5728\u5e38\u89c1\u7684 64<\/code> \u4f4d\u7cfb\u7edf\u4e2d\uff1a<\/p>\n
    fmt.Println(unsafe.Sizeof(value))   \/\/ 0\nfmt.Println(unsafe.Sizeof(pointer)) \/\/ \u901a\u5e38\u4e3a 8\nfmt.Println(unsafe.Sizeof(iface))   \/\/ \u901a\u5e38\u4e3a 16\nfmt.Println(unsafe.Sizeof(slice))   \/\/ \u901a\u5e38\u4e3a 24\nfmt.Println(unsafe.Sizeof(channel)) \/\/ \u901a\u5e38\u4e3a 8\nfmt.Println(unsafe.Sizeof(mapping)) \/\/ \u901a\u5e38\u4e3a 8<\/code><\/pre>\n
    \u8fd9\u4e9b\u6570\u5b57\u4e0e\u5177\u4f53\u5e73\u53f0\u548c\u5b9e\u73b0\u6709\u5173\uff0c\u4f46\u53ef\u4ee5\u8bf4\u660e\u4e00\u4e2a\u95ee\u9898\uff1a<\/p>\n
    struct{}<\/code> \u7684\u503c\u4e0d\u4fdd\u5b58\u6570\u636e\uff0c\u4e0d\u4ee3\u8868\u7ba1\u7406\u8fd9\u4e2a\u503c\u7684\u5bb9\u5668\u4e5f\u6ca1\u6709\u6210\u672c\u3002<\/p><\/blockquote>\n
    \u4f8b\u5982\uff0cmap[T]struct{}<\/code> \u4ecd\u7136\u9700\u8981\u5b58\u50a8 key<\/code>\u3001\u54c8\u5e0c\u6876\u548c\u8fd0\u884c\u65f6\u5143\u6570\u636e\uff1bchan struct{}<\/code> \u4ecd\u7136\u6d89\u53ca\u9501\u3001\u7b49\u5f85\u961f\u5217\u548c goroutine<\/code> \u8c03\u5ea6\u3002<\/p>\n
    3. \u96f6\u5927\u5c0f\u5bf9\u8c61\u7684\u5730\u5740<\/h3>\n
    \u4e0d\u540c\u7684\u96f6\u5927\u5c0f\u53d8\u91cf\u53ef\u80fd\u62e5\u6709\u76f8\u540c\u5730\u5740\uff1a<\/p>\n
    a := struct{}{}\nb := struct{}{}\n\nfmt.Printf("%p\/n", &a)    \/\/ 0x104bdeb20\nfmt.Printf("%p\/n", &b)    \/\/ 0x104bdeb20<\/code><\/pre>\n
    Go \u89c4\u8303\u5141\u8bb8\u4e0d\u540c\u7684\u96f6\u5927\u5c0f\u53d8\u91cf\u62e5\u6709\u76f8\u540c\u5730\u5740\u3002\u7f16\u8bd1\u5668\u6ca1\u6709\u5fc5\u8981\u4e3a\u4e0d\u4fdd\u5b58\u6570\u636e\u7684\u5bf9\u8c61\u5206\u914d\u72ec\u7acb\u7a7a\u95f4\u3002<\/p>\n
    \u56e0\u6b64\uff0c\u4e0b\u9762\u7684\u903b\u8f91\u662f\u4e0d\u53ef\u9760\u7684\uff1a<\/p>\n
    type Token struct{}\n\na := &Token{}\nb := &Token{}\n\n\/\/ \u4e0d\u8981\u901a\u8fc7\u96f6\u5927\u5c0f\u5bf9\u8c61\u7684\u5730\u5740\u5224\u65ad\u5bf9\u8c61\u8eab\u4efd\nif a == b {\n    \/\/ ...\n}\n\n\/\/ \u5982\u679c\u5bf9\u8c61\u9700\u8981\u8eab\u4efd\u8bed\u4e49\uff0c\u5e94\u589e\u52a0 ID \u6216\u975e\u96f6\u5927\u5c0f\u5b57\u6bb5\uff1a\ntype Token struct {\n    ID uint64\n}<\/code><\/pre>\n
    4. \u7a7a\u7ed3\u6784\u4f53\u6570\u7ec4\u548c\u5207\u7247<\/h3>\n
    \u7531\u7a7a\u7ed3\u6784\u4f53\u6784\u6210\u7684\u6570\u7ec4\u4e5f\u53ef\u80fd\u662f\u96f6\u5927\u5c0f\uff1a<\/p>\n
    var values [1_000_000]struct{}\n\nfmt.Println(unsafe.Sizeof(values)) \/\/ 0\nfmt.Println(len(values))           \/\/ 1000000<\/code><\/pre>\n
    \u6570\u7ec4\u957f\u5ea6\u5c5e\u4e8e\u7c7b\u578b\u4fe1\u606f\uff0c\u5143\u7d20\u6570\u91cf\u5f88\u5927\u4e0d\u4ee3\u8868\u9700\u8981\u4e3a\u6bcf\u4e2a\u7a7a\u7ed3\u6784\u4f53\u5206\u914d\u7a7a\u95f4\u3002<\/p>\n
    \u5207\u7247\u5219\u4e0d\u540c\uff1a<\/p>\n
    values := make([]struct{}, 1_000_000)<\/code><\/pre>\n
    \u6bcf\u4e2a\u5143\u7d20\u4e0d\u9700\u8981\u4fdd\u5b58\u6570\u636e\uff0c\u4f46\u5207\u7247\u5934\u4ecd\u7136\u9700\u8981\u4fdd\u5b58\uff1a<\/p>\n
      \n
    • \u5e95\u5c42\u6570\u636e\u6307\u9488<\/li>\n
    • \u957f\u5ea6<\/li>\n
    • \u5bb9\u91cf<\/li>\n<\/ul>\n
      \u540c\u65f6\uff0c\u904d\u5386\u4ecd\u7136\u4f1a\u6267\u884c\u4e00\u767e\u4e07\u6b21\uff1a<\/p>\n
      for range values {\n    \/\/ \u4ecd\u7136\u6267\u884c\u4e00\u767e\u4e07\u6b21\n}<\/code><\/pre>\n
      \u6240\u4ee5\uff0c\u96f6\u5b58\u50a8\u6210\u672c\u4e0d\u4ee3\u8868\u96f6\u8ba1\u7b97\u6210\u672c\u3002<\/p>\n
      5. \u4f7f\u7528 map[T]struct{}<\/code> \u5b9e\u73b0 Set<\/code><\/h3>\n
      Go \u4e2d\u7ecf\u5e38\u4f7f\u7528 map[T]struct{} \u8868\u793a\u96c6\u5408\uff1a<\/p>\n
      languages := map[string]struct{}{\n    "Go":   {},\n    "Java": {},\n}\n\nlanguages["Rust"] = struct{}{}\n\nif _, exists := languages["Go"]; exists {\n    fmt.Println("Go exists")\n}\n\ndelete(languages, "Java")<\/code><\/pre>\n
      \u4e3a\u4ec0\u4e48\u4e0d\u7528 map[T]bool<\/code> \uff1f<\/p>\n
      values := map[string]bool{\n    "Go": false,\n}<\/code><\/pre>\n
      \u6b64\u65f6 “Go” \u4f5c\u4e3a key \u662f\u5b58\u5728\u7684\uff0c\u4f46 value \u53c8\u662f false\uff0c\u8bed\u4e49\u4e0a\u5bb9\u6613\u4ea7\u751f\u6b67\u4e49\u3002<\/p>\n
      map[T]struct{}<\/code> \u8868\u8fbe\u5f97\u66f4\u52a0\u51c6\u786e\uff1a<\/p>\n
      \u53ea\u5173\u5fc3 key \u662f\u5426\u5b58\u5728\uff0c\u4e0d\u9700\u8981\u4fdd\u5b58\u989d\u5916\u72b6\u6001\u3002<\/p><\/blockquote>\n
      \u6cdb\u578b Set \u53ef\u4ee5\u7b80\u5355\u5c01\u88c5\u4e3a\uff1a<\/p>\n
      type Set[T comparable] map[T]struct{}\n\nfunc (s Set[T]) Add(value T) {\n    s[value] = struct{}{}\n}\n\nfunc (s Set[T]) Contains(value T) bool {\n    _, exists := s[value]\n    return exists\n}\n\nfunc (s Set[T]) Remove(value T) {\n    delete(s, value)\n}<\/code><\/pre>\n
      6. \u4f7f\u7528 chan struct{} \u4f20\u9012\u4fe1\u53f7<\/h3>\n
      \u5f53 channel \u53ea\u8d1f\u8d23\u901a\u77e5\u4e8b\u4ef6\u3001\u4e0d\u9700\u8981\u4f20\u9012\u6570\u636e\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528\uff1a<\/p>\n
      done := make(chan struct{})<\/p>\n
      \u5355\u6b21\u901a\u77e5<\/h4>\n
      go func() {\n    done <- struct{}{}\n}()\n\n<-done<\/code><\/pre>\n
      \u5e7f\u64ad\u901a\u77e5<\/h4>\n
      \u5173\u95ed channel \u53ef\u4ee5\u5524\u9192\u6240\u6709\u7b49\u5f85\u63a5\u6536\u7684 goroutine\uff1a<\/p>\n
      done := make(chan struct{})\n\nfor i := 0; i < 3; i++ {\n    go func() {\n        <-done\n        fmt.Println("stopped")\n    }()\n}\n\nclose(done)<\/code><\/pre>\n
      \u8fd9\u4e5f\u662f context.Context \u7684 Done \u65b9\u6cd5\u8fd4\u56de <-chan struct{} \u7684\u539f\u56e0\uff1a<\/p>\n
      select {\ncase <-ctx.Done():\n    return ctx.Err()\ncase result := <-results:\n    return handle(result)\n}<\/code><\/pre>\n
      Done() \u53ea\u8d1f\u8d23\u901a\u77e5\u53d6\u6d88\u4e8b\u4ef6\uff0c\u53d6\u6d88\u539f\u56e0\u901a\u8fc7 ctx.Err() \u83b7\u53d6\u3002<\/p>\n
      \u9700\u8981\u6ce8\u610f\uff1a<\/p>\n