{"id":3626,"date":"2026-03-27T02:16:28","date_gmt":"2026-03-26T18:16:28","guid":{"rendered":"https:\/\/www.go2posts.com\/vi\/using-singleton-pattern-without-global-state-issues\/"},"modified":"2026-03-27T02:16:28","modified_gmt":"2026-03-26T18:16:28","slug":"using-singleton-pattern-without-global-state-issues","status":"publish","type":"post","link":"https:\/\/www.go2posts.com\/vi\/using-singleton-pattern-without-global-state-issues\/","title":{"rendered":"H\u01b0\u1edbng d\u1eabn OOAD: S\u1eed d\u1ee5ng M\u1eabu Singleton m\u00e0 Kh\u00f4ng G\u00e2y V\u1ea5n \u0110\u1ec1 V\u1ec1 Tr\u1ea1ng Th\u00e1i To\u00e0n c\u1ee5c"},"content":{"rendered":"

C\u00e1c m\u1eabu thi\u1ebft k\u1ebf \u0111\u00f3ng vai tr\u00f2 n\u1ec1n t\u1ea3ng cho ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m v\u1eefng ch\u1eafc. Trong s\u1ed1 c\u00e1c m\u1eabu t\u1ea1o l\u1eadp, m\u1eabu Singleton th\u01b0\u1eddng \u0111\u01b0\u1ee3c th\u1ea3o lu\u1eadn nhi\u1ec1u, nh\u01b0ng c\u0169ng th\u01b0\u1eddng b\u1ecb hi\u1ec3u nh\u1ea7m. N\u00f3 \u0111\u1ea3m b\u1ea3o r\u1eb1ng m\u1ed9t l\u1edbp ch\u1ec9 c\u00f3 duy nh\u1ea5t m\u1ed9t th\u1ec3 hi\u1ec7n, cung c\u1ea5p \u0111i\u1ec3m truy c\u1eadp to\u00e0n c\u1ee5c \u0111\u1ebfn n\u00f3. M\u1eb7c d\u00f9 \u0111i\u1ec1u n\u00e0y nghe c\u00f3 v\u1ebb h\u1eefu \u00edch trong vi\u1ec7c qu\u1ea3n l\u00fd t\u00e0i nguy\u00ean, nh\u01b0ng n\u00f3 l\u1ea1i g\u00e2y ra nh\u1eefng th\u00e1ch th\u1ee9c l\u1edbn v\u1ec1 qu\u1ea3n l\u00fd tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c. H\u01b0\u1edbng d\u1eabn n\u00e0y kh\u00e1m ph\u00e1 c\u01a1 ch\u1ebf c\u1ee7a m\u1eabu Singleton, c\u00e1c r\u1ee7i ro li\u00ean quan \u0111\u1ebfn tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c, v\u00e0 c\u00e1c chi\u1ebfn l\u01b0\u1ee3c gi\u1ea3m thi\u1ec3u nh\u1eefng v\u1ea5n \u0111\u1ec1 n\u00e0y trong Ph\u00e2n t\u00edch v\u00e0 Thi\u1ebft k\u1ebf H\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng.<\/p>\n

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<\/figure>\n<\/div>\n

\ud83e\udde9 Hi\u1ec3u v\u1ec1 Singleton trong L\u1eadp tr\u00ecnh H\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng<\/h2>\n

M\u1eabu Singleton \u0111\u1ea3m b\u1ea3o r\u1eb1ng m\u1ed9t l\u1edbp ch\u1ec9 c\u00f3 duy nh\u1ea5t m\u1ed9t th\u1ec3 hi\u1ec7n v\u00e0 cung c\u1ea5p \u0111i\u1ec3m truy c\u1eadp to\u00e0n c\u1ee5c \u0111\u1ebfn n\u00f3. Trong Ph\u00e2n t\u00edch v\u00e0 Thi\u1ebft k\u1ebf H\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng, \u0111i\u1ec1u n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 qu\u1ea3n l\u00fd c\u1ea5u h\u00ecnh, c\u00e1c b\u1ed9 k\u1ebft n\u1ed1i ho\u1eb7c d\u1ecbch v\u1ee5 ghi log. Y\u00eau c\u1ea7u c\u1ed1t l\u00f5i l\u00e0 ki\u1ec3m so\u00e1t nghi\u00eam ng\u1eb7t vi\u1ec7c kh\u1edfi t\u1ea1o.<\/p>\n

    \n
  • H\u00e0m t\u1ea1o ri\u00eang t\u01b0:<\/strong> Ng\u0103n ch\u1eb7n vi\u1ec7c kh\u1edfi t\u1ea1o t\u1eeb b\u00ean ngo\u00e0i b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ngnew<\/code> t\u1eeb kh\u00f3a.<\/li>\n
  • Th\u1ec3 hi\u1ec7n t\u0129nh:<\/strong> L\u01b0u tr\u1eef tham chi\u1ebfu \u0111\u1ebfn \u0111\u1ed1i t\u01b0\u1ee3ng duy nh\u1ea5t b\u00ean trong l\u1edbp.<\/li>\n
  • Ph\u01b0\u01a1ng th\u1ee9c truy c\u1eadp c\u00f4ng khai:<\/strong> M\u1ed9t ph\u01b0\u01a1ng th\u1ee9c t\u0129nh tr\u1ea3 v\u1ec1 th\u1ec3 hi\u1ec7n.<\/li>\n<\/ul>\n

    M\u1eb7c d\u00f9 vi\u1ec7c tri\u1ec3n khai c\u00f3 v\u1ebb \u0111\u01a1n gi\u1ea3n, nh\u01b0ng h\u1ec7 qu\u1ea3 ki\u1ebfn tr\u00fac k\u00e9o d\u00e0i xa h\u01a1n m\u1ed9t l\u1eddi g\u1ecdi ph\u01b0\u01a1ng th\u1ee9c. M\u1eabu n\u00e0y th\u1ef1c ch\u1ea5t t\u1ea1o ra m\u1ed9t bi\u1ebfn to\u00e0n c\u1ee5c, l\u00e0 m\u1ed9t lo\u1ea1i tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c c\u1ee5 th\u1ec3. Tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c \u0111\u1ec1 c\u1eadp \u0111\u1ebfn b\u1ea5t k\u1ef3 d\u1eef li\u1ec7u hay t\u00e0i nguy\u00ean n\u00e0o c\u00f3 th\u1ec3 truy c\u1eadp \u0111\u01b0\u1ee3c t\u1eeb b\u1ea5t k\u1ef3 \u0111\u00e2u trong h\u1ec7 th\u1ed1ng, b\u1ea5t k\u1ec3 ph\u1ea1m vi c\u1ee7a m\u00e3 g\u1ecdi.<\/p>\n

    \ud83d\udeab Chi ph\u00ed \u1ea9n gi\u1ea5u c\u1ee7a tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c<\/h2>\n

    Tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c th\u01b0\u1eddng \u0111\u01b0\u1ee3c nh\u1eafc \u0111\u1ebfn nh\u01b0 m\u1ed9t m\u1eabu ch\u1ed1ng l\u1ea1i trong k\u1ef9 thu\u1eadt ph\u1ea7n m\u1ec1m hi\u1ec7n \u0111\u1ea1i. M\u1eb7c d\u00f9 m\u1eabu Singleton kh\u00f4ng t\u1ef1 th\u00e2n l\u00e0 \u0111i\u1ec1u x\u1ea5u, nh\u01b0ng n\u00f3 l\u00e0m tr\u1ea7m tr\u1ecdng th\u00eam c\u00e1c v\u1ea5n \u0111\u1ec1 li\u00ean quan \u0111\u1ebfn tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c. Hi\u1ec3u r\u00f5 nh\u1eefng v\u1ea5n \u0111\u1ec1 n\u00e0y l\u00e0 b\u01b0\u1edbc \u0111\u1ea7u ti\u00ean \u0111\u1ec3 gi\u1ea3m thi\u1ec3u ch\u00fang.<\/p>\n

    1. G\u1eafn k\u1ebft ch\u1eb7t ch\u1ebd<\/h3>\n

    Khi m\u1ed9t l\u1edbp ph\u1ee5 thu\u1ed9c v\u00e0o m\u1ed9t Singleton, n\u00f3 d\u1ef1a v\u00e0o m\u1ed9t tri\u1ec3n khai c\u1ee5 th\u1ec3 thay v\u00ec m\u1ed9t tr\u1eebu t\u01b0\u1ee3ng. \u0110i\u1ec1u n\u00e0y khi\u1ebfn m\u00e3 ngu\u1ed3n tr\u1edf n\u00ean c\u1ee9ng nh\u1eafc. N\u1ebfu y\u00eau c\u1ea7u thay \u0111\u1ed5i v\u00e0 b\u1ea1n c\u1ea7n thay th\u1ebf tri\u1ec3n khai, m\u1ecdi l\u1edbp tham chi\u1ebfu \u0111\u1ebfn Singleton \u0111\u1ec1u ph\u1ea3i \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt. \u0110i\u1ec1u n\u00e0y vi ph\u1ea1m Nguy\u00ean t\u1eafc \u0110\u1ea3o ng\u01b0\u1ee3c Ph\u1ee5 thu\u1ed9c.<\/p>\n

    2. C\u00e1c ph\u1ee5 thu\u1ed9c \u1ea9n<\/h3>\n

    C\u00e1c ph\u1ee5 thu\u1ed9c n\u00ean \u0111\u01b0\u1ee3c l\u00e0m r\u00f5 r\u00e0ng. V\u1edbi Singleton, ph\u1ee5 thu\u1ed9c tr\u1edf n\u00ean ng\u1ea7m \u0111\u1ecbnh. M\u1ed9t ph\u01b0\u01a1ng th\u1ee9c c\u00f3 th\u1ec3 g\u1ecdi \u0111\u1ebfn Singleton m\u00e0 kh\u00f4ng ghi r\u00f5 trong k\u00fd hi\u1ec7u r\u1eb1ng n\u00f3 c\u1ea7n m\u1ed9t t\u00e0i nguy\u00ean c\u1ee5 th\u1ec3. \u0110i\u1ec1u n\u00e0y khi\u1ebfn m\u00e3 ngu\u1ed3n kh\u00f3 \u0111\u1ecdc v\u00e0 kh\u00f3 hi\u1ec3u h\u01a1n. C\u00e1c l\u1eadp tr\u00ecnh vi\u00ean m\u1edbi ph\u1ea3i theo d\u00f5i to\u00e0n b\u1ed9 ng\u0103n x\u1ebfp g\u1ecdi \u0111\u1ec3 ph\u00e1t hi\u1ec7n t\u00e0i nguy\u00ean n\u00e0o \u0111ang \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng.<\/p>\n

    3. Kh\u00f3 kh\u0103n trong ki\u1ec3m th\u1eed<\/h3>\n

    Ki\u1ec3m th\u1eed l\u00e0 n\u1ea1n nh\u00e2n l\u1edbn nh\u1ea5t c\u1ee7a tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c. Khi m\u1ed9t b\u00e0i ki\u1ec3m th\u1eed \u0111\u01a1n v\u1ecb ch\u1ea1y, n\u00f3 mong \u0111\u1ee3i h\u1ec7 th\u1ed1ng \u1edf tr\u1ea1ng th\u00e1i \u0111\u00e3 bi\u1ebft. N\u1ebfu m\u1ed9t Singleton gi\u1eef tr\u1ea1ng th\u00e1i thay \u0111\u1ed5i t\u1eeb b\u00e0i ki\u1ec3m th\u1eed tr\u01b0\u1edbc, b\u00e0i ki\u1ec3m th\u1eed hi\u1ec7n t\u1ea1i c\u00f3 th\u1ec3 th\u1ea5t b\u1ea1i m\u1ed9t c\u00e1ch b\u1ea5t ng\u1edd. Vi\u1ec7c \u0111\u1eb7t l\u1ea1i m\u1ed9t Singleton th\u01b0\u1eddng \u0111\u00f2i h\u1ecfi ph\u00e1 v\u1ee1 t\u00ednh \u0111\u00f3ng g\u00f3i ho\u1eb7c s\u1eed d\u1ee5ng ph\u1ea3n chi\u1ebfu, \u0111i\u1ec1u n\u00e0y l\u00e0m t\u0103ng \u0111\u1ed9 mong manh cho b\u1ed9 ki\u1ec3m th\u1eed.<\/p>\n

    4. V\u1ea5n \u0111\u1ec1 \u0111\u1ed3ng th\u1eddi<\/h3>\n

    Trong m\u00f4i tr\u01b0\u1eddng \u0111a lu\u1ed3ng, truy c\u1eadp v\u00e0o m\u1ed9t th\u1ec3 hi\u1ec7n chung m\u00e0 kh\u00f4ng c\u00f3 \u0111\u1ed3ng b\u1ed9 h\u00f3a th\u00edch h\u1ee3p c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn \u0111i\u1ec1u ki\u1ec7n \u0111ua. N\u1ebfu Singleton \u0111\u01b0\u1ee3c kh\u1edfi t\u1ea1o theo c\u00e1ch tr\u00ec ho\u00e3n, hai lu\u1ed3ng c\u00f3 th\u1ec3 c\u00f9ng c\u1ed1 g\u1eafng t\u1ea1o th\u1ec3 hi\u1ec7n \u0111\u1ed3ng th\u1eddi, d\u1eabn \u0111\u1ebfn vi\u1ec7c t\u1ea1o ra nhi\u1ec1u th\u1ec3 hi\u1ec7n. \u0110i\u1ec1u n\u00e0y vi ph\u1ea1m h\u1ee3p \u0111\u1ed3ng c\u1ed1t l\u00f5i c\u1ee7a m\u1eabu.<\/p>\n

    \u26a1 Tri\u1ec3n khai Singleton an to\u00e0n cho \u0111a lu\u1ed3ng<\/h2>\n

    \u0110\u1ec3 s\u1eed d\u1ee5ng m\u1eabu Singleton m\u1ed9t c\u00e1ch an to\u00e0n, c\u1ea7n gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 \u0111\u1ed3ng th\u1eddi. C\u00f3 m\u1ed9t s\u1ed1 c\u00e1ch ti\u1ebfp c\u1eadn \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o an to\u00e0n \u0111a lu\u1ed3ng m\u00e0 kh\u00f4ng l\u00e0m gi\u1ea3m hi\u1ec7u su\u1ea5t.<\/p>\n

      \n
    • Kh\u1edfi t\u1ea1o s\u1edbm:<\/strong> Th\u1ec3 hi\u1ec7n \u0111\u01b0\u1ee3c t\u1ea1o khi l\u1edbp \u0111\u01b0\u1ee3c t\u1ea3i. \u0110i\u1ec1u n\u00e0y t\u1ef1 nhi\u00ean an to\u00e0n \u0111a lu\u1ed3ng v\u00ec vi\u1ec7c t\u1ea3i l\u1edbp \u0111\u01b0\u1ee3c \u0111\u1ed3ng b\u1ed9 h\u00f3a b\u1edfi m\u00f4i tr\u01b0\u1eddng ch\u1ea1y. Tuy nhi\u00ean, n\u00f3 c\u00f3 th\u1ec3 l\u00e3ng ph\u00ed t\u00e0i nguy\u00ean n\u1ebfu th\u1ec3 hi\u1ec7n kh\u00f4ng bao gi\u1edd \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng.<\/li>\n
    • Kh\u1edfi t\u1ea1o tr\u00ec ho\u00e3n v\u1edbi kh\u00f3a:<\/strong> Th\u1ec3 hi\u1ec7n \u0111\u01b0\u1ee3c t\u1ea1o khi truy c\u1eadp l\u1ea7n \u0111\u1ea7u. M\u1ed9t kh\u00f3a \u0111\u1ea3m b\u1ea3o ch\u1ec9 c\u00f3 m\u1ed9t lu\u1ed3ng t\u1ea1o n\u00f3. C\u00e1ch n\u00e0y \u0111\u01a1n gi\u1ea3n nh\u01b0ng c\u00f3 th\u1ec3 tr\u1edf th\u00e0nh \u0111i\u1ec3m ngh\u1ebdn hi\u1ec7u su\u1ea5t n\u1ebfu ph\u01b0\u01a1ng th\u1ee9c truy c\u1eadp \u0111\u01b0\u1ee3c g\u1ecdi th\u01b0\u1eddng xuy\u00ean.<\/li>\n
    • Kh\u00f3a ki\u1ec3m tra k\u00e9p:<\/strong> Ki\u1ec3m tra xem phi\u00ean b\u1ea3n c\u00f3 t\u1ed3n t\u1ea1i hay kh\u00f4ng tr\u01b0\u1edbc khi chi\u1ebfm gi\u1eef kh\u00f3a. \u0110i\u1ec1u n\u00e0y l\u00e0m gi\u1ea3m chi ph\u00ed kh\u00f3a nh\u01b0ng \u0111\u00f2i h\u1ecfi x\u1eed l\u00fd c\u1ea9n th\u1eadn c\u00e1c r\u00e0o c\u1ea3n b\u1ed9 nh\u1edb \u0111\u1ec3 tr\u00e1nh c\u00e1c v\u1ea5n \u0111\u1ec1 s\u1eafp x\u1ebfp l\u1ea1i.<\/li>\n
    • Kh\u1ed1i kh\u1edfi t\u1ea1o:<\/strong>S\u1eed d\u1ee5ng kh\u1ed1i t\u0129nh ho\u1eb7c m\u1ed9t l\u1edbp tr\u1ee3 gi\u00fap t\u0129nh b\u00ean trong (gi\u1ea3i ph\u00e1p c\u1ee7a Bill Pugh) \u0111\u1ea3m b\u1ea3o an to\u00e0n cho lu\u1ed3ng m\u00e0 kh\u00f4ng c\u1ea7n kh\u00f3a r\u00f5 r\u00e0ng. JVM s\u1ebd x\u1eed l\u00fd \u0111\u1ed3ng b\u1ed9 h\u00f3a trong qu\u00e1 tr\u00ecnh t\u1ea3i l\u1edbp.<\/li>\n<\/ul>\n

      M\u1ed7i ph\u01b0\u01a1ng ph\u00e1p \u0111\u1ec1u c\u00f3 nh\u1eefng \u01b0u nh\u01b0\u1ee3c \u0111i\u1ec3m. Kh\u1edfi t\u1ea1o nhanh \u0111\u01a1n gi\u1ea3n nh\u01b0ng thi\u1ebfu linh ho\u1ea1t. Kh\u00f3a ki\u1ec3m tra k\u00e9p hi\u1ec7u qu\u1ea3 nh\u01b0ng ph\u1ee9c t\u1ea1p. Kh\u1ed1i kh\u1edfi t\u1ea1o th\u01b0\u1eddng \u0111\u01b0\u1ee3c khuy\u1ebfn ngh\u1ecb l\u00e0 c\u00e1ch ti\u1ebfp c\u1eadn cho c\u00e1c singleton t\u0129nh.<\/p>\n

      \ud83d\udd04 C\u00e1c l\u1ef1a ch\u1ecdn thay th\u1ebf cho M\u1eabu Singleton<\/h2>\n

      X\u00e9t \u0111\u1ebfn nh\u1eefng r\u1ee7i ro c\u1ee7a tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c, nhi\u1ec1u ki\u1ebfn tr\u00fac s\u01b0 \u01b0u ti\u00ean c\u00e1c l\u1ef1a ch\u1ecdn thay th\u1ebf \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ee5c ti\u00eau t\u01b0\u01a1ng t\u1ef1 m\u00e0 kh\u00f4ng c\u00f3 nh\u01b0\u1ee3c \u0111i\u1ec3m. C\u00e1c m\u1eabu n\u00e0y th\u00fac \u0111\u1ea9y s\u1ef1 li\u00ean k\u1ebft l\u1ecfng l\u1ebbo v\u00e0 d\u1ec5 ki\u1ec3m th\u1eed h\u01a1n.<\/p>\n

      1. Ch\u00e8n ph\u1ee5 thu\u1ed9c (DI)<\/h3>\n

      Ch\u00e8n ph\u1ee5 thu\u1ed9c l\u00e0 l\u1ef1a ch\u1ecdn thay th\u1ebf ti\u00eau chu\u1ea9n. Thay v\u00ec m\u1ed9t l\u1edbp truy xu\u1ea5t tr\u1ef1c ti\u1ebfp m\u1ed9t Singleton, Singleton (ho\u1eb7c d\u1ecbch v\u1ee5 m\u00e0 n\u00f3 \u0111\u1ea1i di\u1ec7n) \u0111\u01b0\u1ee3c truy\u1ec1n v\u00e0o l\u1edbp, th\u01b0\u1eddng th\u00f4ng qua h\u00e0m t\u1ea1o. \u0110i\u1ec1u n\u00e0y l\u00e0m cho ph\u1ee5 thu\u1ed9c tr\u1edf n\u00ean r\u00f5 r\u00e0ng v\u00e0 cho ph\u00e9p ng\u01b0\u1eddi ti\u00eau d\u00f9ng nh\u1eadn \u0111\u01b0\u1ee3c m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng gi\u1ea3 ho\u1eb7c gi\u1ea3 l\u1eadp trong qu\u00e1 tr\u00ecnh ki\u1ec3m th\u1eed.<\/p>\n

      Logic v\u00ed d\u1ee5:<\/p>\n

        \n
      • X\u00e1c \u0111\u1ecbnh m\u1ed9t giao di\u1ec7n cho d\u1ecbch v\u1ee5.<\/li>\n
      • T\u1ea1o m\u1ed9t tri\u1ec3n khai c\u1ee5 th\u1ec3.<\/li>\n
      • \u0110\u0103ng k\u00fd tri\u1ec3n khai v\u1edbi m\u1ed9t b\u1ed9 ch\u1ee9a ho\u1eb7c truy\u1ec1n n\u00f3 th\u1ee7 c\u00f4ng.<\/li>\n
      • Ch\u00e8n giao di\u1ec7n v\u00e0o l\u1edbp c\u1ea7n s\u1eed d\u1ee5ng n\u00f3.<\/li>\n<\/ul>\n

        2. B\u1ed9 \u0111\u1ecbnh v\u1ecb d\u1ecbch v\u1ee5<\/h3>\n

        B\u1ed9 \u0111\u1ecbnh v\u1ecb d\u1ecbch v\u1ee5 l\u00e0 m\u1ed9t danh s\u00e1ch c\u00e1c d\u1ecbch v\u1ee5. M\u1ed9t l\u1edbp y\u00eau c\u1ea7u b\u1ed9 \u0111\u1ecbnh v\u1ecb cung c\u1ea5p d\u1ecbch v\u1ee5 thay v\u00ec t\u1ef1 t\u1ea1o ra n\u00f3. M\u1eb7c d\u00f9 \u0111i\u1ec1u n\u00e0y l\u00e0m gi\u1ea3m s\u1ef1 li\u00ean k\u1ebft so v\u1edbi truy c\u1eadp Singleton tr\u1ef1c ti\u1ebfp, nh\u01b0ng n\u00f3 v\u1eabn \u1ea9n c\u00e1c ph\u1ee5 thu\u1ed9c. Th\u01b0\u1eddng \u0111\u01b0\u1ee3c xem l\u00e0 m\u1ed9t bi\u1ebfn th\u1ec3 c\u1ee7a m\u1eabu ch\u1ed1ng \u0111\u1ecbnh v\u1ecb d\u1ecbch v\u1ee5.<\/p>\n

        3. M\u1eabu nh\u00e0 m\u00e1y<\/h3>\n

        M\u1ed9t nh\u00e0 m\u00e1y t\u1ea1o ra c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng. N\u1ebfu nh\u00e0 m\u00e1y \u0111\u1ea3m b\u1ea3o ch\u1ec9 c\u00f3 m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng \u0111\u01b0\u1ee3c t\u1ea1o ra v\u00e0 l\u01b0u tr\u1eef n\u00f3, n\u00f3 s\u1ebd m\u00f4 ph\u1ecfng h\u00e0nh vi c\u1ee7a Singleton. Tuy nhi\u00ean, ch\u00ednh nh\u00e0 m\u00e1y c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ch\u00e8n v\u00e0o, cho ph\u00e9p thay \u0111\u1ed5i ho\u1eb7c gi\u1ea3 l\u1eadp logic m\u00e0 kh\u00f4ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn m\u00e3 kh\u00e1ch h\u00e0ng.<\/p>\n

        \ud83d\udcca So s\u00e1nh c\u00e1c ph\u01b0\u01a1ng ph\u00e1p qu\u1ea3n l\u00fd tr\u1ea1ng th\u00e1i<\/h2>\n

        B\u1ea3ng sau t\u00f3m t\u1eaft c\u00e1c \u01b0u nh\u01b0\u1ee3c \u0111i\u1ec3m gi\u1eefa vi\u1ec7c qu\u1ea3n l\u00fd tr\u1ea1ng th\u00e1i th\u00f4ng qua Singleton, Ch\u00e8n ph\u1ee5 thu\u1ed9c v\u00e0 M\u1eabu nh\u00e0 m\u00e1y.<\/p>\n\n\n\n\n\n\n\n
        T\u00ednh n\u0103ng<\/th>\nSingleton<\/th>\nCh\u00e8n ph\u1ee5 thu\u1ed9c<\/th>\nNh\u00e0 m\u00e1y<\/th>\n<\/tr>\n
        Tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c<\/td>\nCao<\/td>\nTh\u1ea5p<\/td>\nTrung b\u00ecnh<\/td>\n<\/tr>\n
        Kh\u1ea3 n\u0103ng ki\u1ec3m th\u1eed<\/td>\nTh\u1ea5p<\/td>\nCao<\/td>\nTrung b\u00ecnh<\/td>\n<\/tr>\n
        An to\u00e0n lu\u1ed3ng<\/td>\nY\u00eau c\u1ea7u x\u1eed l\u00fd th\u1ee7 c\u00f4ng<\/td>\nQu\u1ea3n l\u00fd b\u1edfi container<\/td>\nQu\u1ea3n l\u00fd b\u1edfi tri\u1ec3n khai<\/td>\n<\/tr>\n
        Li\u00ean k\u1ebft<\/td>\nCh\u1eb7t ch\u1ebd<\/td>\nL\u1ecfng l\u1ebbo<\/td>\nL\u1ecfng l\u1ebbo<\/td>\n<\/tr>\n
        Hi\u1ec7u su\u1ea5t<\/td>\nNhanh (truy c\u1eadp tr\u1ef1c ti\u1ebfp)<\/td>\nThay \u0111\u1ed5i (chi ph\u00ed ch\u00e8n)<\/td>\nThay \u0111\u1ed5i (chi ph\u00ed nh\u00e0 m\u00e1y)<\/td>\n<\/tr>\n<\/table>\n

        \ud83d\udce6 Qu\u1ea3n l\u00fd tr\u1ea1ng th\u00e1i \u0111\u1ec3 kh\u1ea3 n\u0103ng ki\u1ec3m th\u1eed<\/h2>\n

        N\u1ebfu b\u1ea1n ph\u1ea3i s\u1eed d\u1ee5ng Singleton, b\u1ea1n ph\u1ea3i \u0111\u1ea3m b\u1ea3o n\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ki\u1ec3m th\u1eed. \u0110i\u1ec1u n\u00e0y \u0111\u00f2i h\u1ecfi ph\u1ea3i x\u1eed l\u00fd Singleton nh\u01b0 m\u1ed9t t\u00e0i nguy\u00ean c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111\u1eb7t l\u1ea1i ho\u1eb7c thay th\u1ebf.<\/p>\n

          \n
        • S\u1eed d\u1ee5ng giao di\u1ec7n:<\/strong>Lu\u00f4n ph\u1ee5 thu\u1ed9c v\u00e0o m\u1ed9t giao di\u1ec7n, ch\u1ee9 kh\u00f4ng ph\u1ea3i l\u1edbp Singleton c\u1ee5 th\u1ec3. \u0110i\u1ec1u n\u00e0y cho ph\u00e9p b\u1ea1n ch\u00e8n m\u1ed9t tri\u1ec3n khai gi\u1ea3.<\/li>\n
        • C\u01a1 ch\u1ebf \u0111\u1eb7t l\u1ea1i:<\/strong>Cung c\u1ea5p m\u1ed9t ph\u01b0\u01a1ng th\u1ee9c t\u0129nh \u0111\u1ec3 x\u00f3a b\u1ea3n th\u1ec3. \u0110i\u1ec1u n\u00e0y ch\u1ec9 n\u00ean \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong m\u00f4i tr\u01b0\u1eddng ki\u1ec3m th\u1eed \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o s\u1ef1 t\u00e1ch bi\u1ec7t tr\u1ea1ng th\u00e1i gi\u1eefa c\u00e1c tr\u01b0\u1eddng h\u1ee3p ki\u1ec3m th\u1eed.<\/li>\n
        • Qu\u1ea3n l\u00fd ph\u1ea1m vi:<\/strong>Trong c\u00e1c \u1ee9ng d\u1ee5ng web, qu\u1ea3n l\u00fd v\u00f2ng \u0111\u1eddi c\u1ee7a Singleton theo t\u1eebng y\u00eau c\u1ea7u ho\u1eb7c phi\u00ean n\u1ebfu n\u00f3 l\u01b0u tr\u1eef d\u1eef li\u1ec7u c\u1ee5 th\u1ec3 ng\u01b0\u1eddi d\u00f9ng. M\u1ed9t Singleton th\u1ef1c s\u1ef1 kh\u00f4ng n\u00ean l\u01b0u tr\u1eef d\u1eef li\u1ec7u ng\u01b0\u1eddi d\u00f9ng t\u1ea1m th\u1eddi.<\/li>\n<\/ul>\n

          H\u00e3y xem x\u00e9t t\u00ecnh hu\u1ed1ng m\u00e0 m\u1ed9t Singleton l\u01b0u tr\u1eef k\u1ebft n\u1ed1i c\u01a1 s\u1edf d\u1eef li\u1ec7u. N\u1ebfu b\u1ed9 ki\u1ec3m th\u1eed ch\u1ea1y nhi\u1ec1u ki\u1ec3m th\u1eed thay \u0111\u1ed5i c\u01a1 s\u1edf d\u1eef li\u1ec7u, tr\u1ea1ng th\u00e1i s\u1ebd v\u1eabn t\u1ed3n t\u1ea1i. S\u1eed d\u1ee5ng container DI cho ph\u00e9p b\u1ea1n cung c\u1ea5p m\u1ed9t k\u1ebft n\u1ed1i m\u1edbi cho m\u1ed7i ki\u1ec3m th\u1eed, \u0111\u1ea3m b\u1ea3o s\u1ef1 t\u00e1ch bi\u1ec7t.<\/p>\n

          \ud83d\udee0\ufe0f T\u00e1i c\u1ea5u tr\u00fac Singleton \u0111\u1ec3 tr\u00e1nh tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c<\/h2>\n

          T\u00e1i c\u1ea5u tr\u00fac m\u1ed9t h\u1ec7 th\u1ed1ng c\u0169 \u0111\u1ec3 lo\u1ea1i b\u1ecf tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c \u0111\u00f2i h\u1ecfi m\u1ed9t c\u00e1ch ti\u1ebfp c\u1eadn c\u00f3 h\u1ec7 th\u1ed1ng. B\u1ea1n kh\u00f4ng th\u1ec3 \u0111\u01a1n gi\u1ea3n x\u00f3a Singleton m\u00e0 kh\u00f4ng l\u00e0m h\u1ecfng \u1ee9ng d\u1ee5ng.<\/p>\n

            \n
          1. X\u00e1c \u0111\u1ecbnh ph\u1ee5 thu\u1ed9c:<\/strong>Li\u1ec7t k\u00ea t\u1ea5t c\u1ea3 c\u00e1c l\u1edbp g\u1ecdi tr\u1ef1c ti\u1ebfp \u0111\u1ebfn Singleton.<\/li>\n
          2. Gi\u1edbi thi\u1ec7u m\u1ed9t giao di\u1ec7n:<\/strong>T\u1ea1o m\u1ed9t giao di\u1ec7n \u0111\u1ecbnh ngh\u0129a c\u00e1c ph\u01b0\u01a1ng th\u1ee9c \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng b\u1edfi Singleton.<\/li>\n
          3. Tri\u1ec3n khai giao di\u1ec7n:<\/strong>\u0110\u1ea3m b\u1ea3o Singleton tri\u1ec3n khai giao di\u1ec7n n\u00e0y.<\/li>\n
          4. Ti\u00eam giao di\u1ec7n:<\/strong>S\u1eeda \u0111\u1ed5i c\u00e1c l\u1edbp ph\u1ee5 thu\u1ed9c \u0111\u1ec3 ch\u1ea5p nh\u1eadn giao di\u1ec7n th\u00f4ng qua ti\u00eam v\u00e0o constructor ho\u1eb7c ph\u01b0\u01a1ng th\u1ee9c thi\u1ebft l\u1eadp.<\/li>\n
          5. K\u1ebft n\u1ed1i th\u1ec3 hi\u1ec7n:<\/strong>T\u1ea1i \u0111i\u1ec3m v\u00e0o \u1ee9ng d\u1ee5ng, kh\u1edfi t\u1ea1o th\u1ec3 hi\u1ec7n Singleton v\u00e0 truy\u1ec1n n\u00f3 cho c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng g\u1ed1c.<\/li>\n
          6. X\u00e1c minh:<\/strong>Ch\u1ea1y b\u1ed9 ki\u1ec3m th\u1eed \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o h\u00e0nh vi v\u1eabn gi\u1eef \u0111\u01b0\u1ee3c t\u00ednh nh\u1ea5t qu\u00e1n.<\/li>\n<\/ol>\n

            Quy tr\u00ecnh n\u00e0y chuy\u1ec3n \u0111\u1ed5i m\u1ed9t ph\u1ee5 thu\u1ed9c \u1ea9n th\u00e0nh m\u1ed9t ph\u1ee5 thu\u1ed9c r\u00f5 r\u00e0ng. N\u00f3 t\u0103ng t\u00ednh r\u00f5 r\u00e0ng c\u1ee7a m\u00e3 ngu\u1ed3n v\u00e0 gi\u1ea3m nguy c\u01a1 t\u00e1c \u0111\u1ed9ng ph\u1ee5.<\/p>\n

            \u2696\ufe0f Khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng Singleton<\/h2>\n

            M\u1eb7c d\u00f9 ti\u1ec1m \u1ea9n r\u1ee7i ro, Singleton v\u1eabn ph\u00f9 h\u1ee3p trong m\u1ed9t s\u1ed1 t\u00ecnh hu\u1ed1ng c\u1ee5 th\u1ec3. \u0110i\u1ec1u quan tr\u1ecdng l\u00e0 gi\u1edbi h\u1ea1n ph\u1ea1m vi v\u00e0 c\u00e1ch s\u1eed d\u1ee5ng c\u1ee7a ch\u00fang.<\/p>\n

              \n
            • Tr\u00ecnh qu\u1ea3n l\u00fd c\u1ea5u h\u00ecnh:<\/strong>\u0110\u1ecdc c\u00e0i \u0111\u1eb7t khi kh\u1edfi \u0111\u1ed9ng l\u00e0 m\u1ed9t tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng ph\u1ed5 bi\u1ebfn. V\u00ec c\u1ea5u h\u00ecnh hi\u1ebfm khi thay \u0111\u1ed5i trong qu\u00e1 tr\u00ecnh ch\u1ea1y, vi\u1ec7c truy c\u1eadp to\u00e0n c\u1ee5c l\u00e0 ch\u1ea5p nh\u1eadn \u0111\u01b0\u1ee3c.<\/li>\n
            • H\u1ec7 th\u1ed1ng ghi nh\u1eadt k\u00fd:<\/strong>M\u1ed9t c\u01a1 ch\u1ebf ghi nh\u1eadt k\u00fd t\u1eadp trung th\u01b0\u1eddng \u0111\u01b0\u1ee3c l\u1ee3i t\u1eeb m\u1ed9t \u0111i\u1ec3m ki\u1ec3m so\u00e1t duy nh\u1ea5t \u0111\u1ec3 qu\u1ea3n l\u00fd lu\u1ed3ng \u0111\u1ea7u ra v\u00e0 \u0111\u1ecbnh d\u1ea1ng.<\/li>\n
            • C\u00e1c nh\u00f3m t\u00e0i nguy\u00ean:<\/strong>C\u00e1c nh\u00f3m k\u1ebft n\u1ed1i ho\u1eb7c nh\u00f3m lu\u1ed3ng c\u1ea7n qu\u1ea3n l\u00fd m\u1ed9t t\u1eadp h\u1ee3p t\u00e0i nguy\u00ean h\u1eefu h\u1ea1n. M\u1ed9t Singleton \u0111\u1ea3m b\u1ea3o nh\u00f3m n\u00e0y \u0111\u01b0\u1ee3c chia s\u1ebb hi\u1ec7u qu\u1ea3 tr\u00ean to\u00e0n \u1ee9ng d\u1ee5ng.<\/li>\n<\/ul>\n

              Trong c\u00e1c tr\u01b0\u1eddng h\u1ee3p n\u00e0y, tr\u1ea1ng th\u00e1i l\u00e0 t\u1ed1i thi\u1ec3u ho\u1eb7c b\u1ea5t bi\u1ebfn. Singleton qu\u1ea3n l\u00fd t\u00e0i nguy\u00ean, ch\u1ee9 kh\u00f4ng ph\u1ea3i logic kinh doanh. S\u1ef1 ph\u00e2n bi\u1ec7t n\u00e0y l\u00e0 r\u1ea5t quan tr\u1ecdng. M\u1ed9t Singleton ch\u1ee9a logic kinh doanh l\u00e0 d\u1ea5u hi\u1ec7u c\u1ee7a m\u00e3 ngu\u1ed3n k\u00e9m ch\u1ea5t l\u01b0\u1ee3ng.<\/p>\n

              \ud83d\udd12 C\u00e1c v\u1ea5n \u0111\u1ec1 b\u1ea3o m\u1eadt<\/h2>\n

              Tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c mang l\u1ea1i r\u1ee7i ro b\u1ea3o m\u1eadt. N\u1ebfu m\u1ed9t Singleton l\u01b0u tr\u1eef d\u1eef li\u1ec7u nh\u1ea1y c\u1ea3m nh\u01b0 kh\u00f3a m\u00e3 h\u00f3a ho\u1eb7c m\u00e3 x\u00e1c th\u1ef1c, n\u00f3 tr\u1edf th\u00e0nh m\u1ee5c ti\u00eau c\u00f3 gi\u00e1 tr\u1ecb cao. M\u1ecdi m\u00e3 trong h\u1ec7 th\u1ed1ng \u0111\u1ec1u c\u00f3 th\u1ec3 truy c\u1eadp v\u00e0o n\u00f3.<\/p>\n

                \n
              • Nguy\u00ean t\u1eafc \u00edt quy\u1ec1n h\u1ea1n nh\u1ea5t:<\/strong>\u0110\u1ea3m b\u1ea3o r\u1eb1ng ch\u1ec9 c\u00e1c th\u00e0nh ph\u1ea7n c\u1ea7n thi\u1ebft m\u1edbi c\u00f3 quy\u1ec1n truy c\u1eadp v\u00e0o Singleton.<\/li>\n
              • C\u00e1ch ly d\u1eef li\u1ec7u:<\/strong>Kh\u00f4ng l\u01b0u tr\u1eef d\u1eef li\u1ec7u c\u1ee5 th\u1ec3 ng\u01b0\u1eddi d\u00f9ng trong m\u1ed9t Singleton c\u1ea5p ti\u1ebfn tr\u00ecnh. Thay v\u00e0o \u0111\u00f3, h\u00e3y s\u1eed d\u1ee5ng b\u1ed9 nh\u1edb l\u01b0u tr\u1eef theo phi\u00ean thay th\u1ebf.<\/li>\n
              • M\u00e3 h\u00f3a:<\/strong>N\u1ebfu d\u1eef li\u1ec7u nh\u1ea1y c\u1ea3m ph\u1ea3i \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef, h\u00e3y \u0111\u1ea3m b\u1ea3o n\u00f3 \u0111\u01b0\u1ee3c m\u00e3 h\u00f3a khi l\u01b0u tr\u1eef v\u00e0 trong b\u1ed9 nh\u1edb.<\/li>\n<\/ul>\n

                \ud83d\udcc9 H\u1ec7 qu\u1ea3 v\u1ec1 hi\u1ec7u su\u1ea5t<\/h2>\n

                S\u1eed d\u1ee5ng Singleton c\u00f3 th\u1ec3 c\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t b\u1eb1ng c\u00e1ch gi\u1ea3m chi ph\u00ed ph\u00e1t sinh khi t\u1ea1o \u0111\u1ed1i t\u01b0\u1ee3ng. Tuy nhi\u00ean, l\u1ee3i \u00edch n\u00e0y th\u01b0\u1eddng kh\u00f4ng \u0111\u00e1ng k\u1ec3 trong m\u00f4i tr\u01b0\u1eddng hi\u1ec7n \u0111\u1ea1i n\u01a1i vi\u1ec7c c\u1ea5p ph\u00e1t \u0111\u1ed1i t\u01b0\u1ee3ng l\u00e0 r\u1ebb. Chi ph\u00ed kh\u00f3a \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o an to\u00e0n cho lu\u1ed3ng c\u00f3 th\u1ec3 v\u01b0\u1ee3t tr\u1ed9i h\u01a1n so v\u1edbi l\u1ee3i \u00edch c\u1ee7a vi\u1ec7c duy tr\u00ec m\u1ed9t th\u1ec3 hi\u1ec7n duy nh\u1ea5t.<\/p>\n

                H\u01a1n n\u1eefa, n\u1ebfu Singleton l\u01b0u tr\u1eef tr\u1ea1ng th\u00e1i th\u01b0\u1eddng xuy\u00ean b\u1ecb thay \u0111\u1ed5i, n\u00f3 c\u00f3 th\u1ec3 tr\u1edf th\u00e0nh \u0111i\u1ec3m ngh\u1ebdn. Nhi\u1ec1u lu\u1ed3ng truy c\u1eadp c\u00f9ng m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng c\u00f3 th\u1ec3 c\u1ea1nh tranh \u0111\u1ec3 gi\u00e0nh kh\u00f3a, l\u00e0m gi\u1ea3m b\u0103ng th\u00f4ng. Trong c\u00e1c h\u1ec7 th\u1ed1ng c\u00f3 \u0111\u1ed9 \u0111\u1ed3ng th\u1eddi cao, c\u00e1c d\u1ecbch v\u1ee5 kh\u00f4ng tr\u1ea1ng th\u00e1i th\u01b0\u1eddng \u0111\u01b0\u1ee3c \u01b0u ti\u00ean h\u01a1n l\u00e0 c\u00e1c Singleton c\u00f3 tr\u1ea1ng th\u00e1i.<\/p>\n

                \ud83e\udded C\u00e1c nguy\u00ean t\u1eafc ki\u1ebfn tr\u00fac<\/h2>\n

                \u0110\u1ec3 duy tr\u00ec ki\u1ebfn tr\u00fac s\u1ea1ch s\u1ebd, h\u00e3y tu\u00e2n theo c\u00e1c nguy\u00ean t\u1eafc sau khi l\u00e0m vi\u1ec7c v\u1edbi Singleton:<\/p>\n

                  \n
                • Gi\u1eef n\u00f3 kh\u00f4ng tr\u1ea1ng th\u00e1i:<\/strong> \u01afu ti\u00ean c\u00e1c Singleton ho\u1ea1t \u0111\u1ed9ng nh\u01b0 c\u00e1c qu\u1ea3n l\u00fd ho\u1eb7c \u0111i\u1ec1u ph\u1ed1i vi\u00ean thay v\u00ec c\u00e1c b\u1ed9 l\u01b0u tr\u1eef d\u1eef li\u1ec7u.<\/li>\n
                • Gi\u1edbi h\u1ea1n ph\u1ea1m vi:<\/strong> N\u1ebfu c\u00f3 th\u1ec3, h\u00e3y s\u1eed d\u1ee5ng ph\u1ea1m vi Request ho\u1eb7c Session thay v\u00ec ph\u1ea1m vi Application.<\/li>\n
                • T\u00e0i li\u1ec7u s\u1eed d\u1ee5ng:<\/strong> R\u00f5 r\u00e0ng t\u00e0i li\u1ec7u l\u00fd do t\u1ea1i sao s\u1eed d\u1ee5ng Singleton. N\u1ebfu l\u00fd do l\u00e0 \u201cgi\u00fap truy c\u1eadp d\u1ec5 d\u00e0ng h\u01a1n\u201d, th\u00ec \u0111\u00f3 kh\u00f4ng ph\u1ea3i l\u00e0 l\u00fd do h\u1ee3p l\u1ec7.<\/li>\n
                • Tr\u00e1nh c\u00e1c Singleton l\u1ed3ng nhau:<\/strong> Kh\u00f4ng t\u1ea1o c\u00e1c Singleton ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1c Singleton kh\u00e1c. \u0110i\u1ec1u n\u00e0y t\u1ea1o ra m\u1ed9t m\u1ea1ng l\u01b0\u1edbi c\u00e1c ph\u1ee5 thu\u1ed9c \u1ea9n.<\/li>\n<\/ul>\n

                  B\u1eb1ng c\u00e1ch tu\u00e2n theo c\u00e1c nguy\u00ean t\u1eafc n\u00e0y, b\u1ea1n c\u00f3 th\u1ec3 t\u1eadn d\u1ee5ng l\u1ee3i \u00edch c\u1ee7a m\u1eabu Singleton trong khi gi\u1ea3m thi\u1ec3u c\u00e1c r\u1ee7i ro li\u00ean quan \u0111\u1ebfn tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c. M\u1ee5c ti\u00eau kh\u00f4ng ph\u1ea3i l\u00e0 c\u1ea5m ho\u00e0n to\u00e0n m\u1eabu n\u00e0y, m\u00e0 l\u00e0 s\u1eed d\u1ee5ng n\u00f3 m\u1ed9t c\u00e1ch c\u00f3 ch\u1ee7 \u00fd v\u00e0 k\u1ef7 lu\u1eadt.<\/p>\n

                  \ud83d\udd0d Nh\u1eefng suy ngh\u0129 cu\u1ed1i c\u00f9ng v\u1ec1 tri\u1ec3n khai<\/h2>\n

                  Vi\u1ec7c quy\u1ebft \u0111\u1ecbnh s\u1eed d\u1ee5ng Singleton c\u1ea7n mang t\u00ednh ki\u1ebfn tr\u00fac, ch\u1ee9 kh\u00f4ng ph\u1ea3i ng\u1eabu nhi\u00ean. N\u00f3 \u0111\u00f2i h\u1ecfi s\u1ef1 hi\u1ec3u r\u00f5 v\u1ec1 v\u00f2ng \u0111\u1eddi c\u1ee7a d\u1eef li\u1ec7u m\u00e0 n\u00f3 qu\u1ea3n l\u00fd. Khi tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c l\u00e0 kh\u00f4ng th\u1ec3 tr\u00e1nh kh\u1ecfi, th\u00ec ph\u1ea3i qu\u1ea3n l\u00fd n\u00f3 v\u1edbi c\u00f9ng m\u1ee9c \u0111\u1ed9 nghi\u00eam ng\u1eb7t nh\u01b0 b\u1ea5t k\u1ef3 t\u00e0i nguy\u00ean chia s\u1ebb n\u00e0o kh\u00e1c. Vi\u1ec7c \u0111\u1ed3ng b\u1ed9 h\u00f3a, c\u00f4 l\u1eadp v\u00e0 kh\u1ea3 n\u0103ng ki\u1ec3m th\u1eed ph\u1ea3i \u0111\u01b0\u1ee3c t\u00edch h\u1ee3p v\u00e0o thi\u1ebft k\u1ebf t\u1eeb \u0111\u1ea7u.<\/p>\n

                  C\u00e1c khung c\u00f4ng t\u00e1c hi\u1ec7n \u0111\u1ea1i th\u01b0\u1eddng cung c\u1ea5p c\u00e1c c\u01a1 ch\u1ebf t\u00edch h\u1ee3p \u0111\u1ec3 qu\u1ea3n l\u00fd c\u00e1c th\u1ec3 hi\u1ec7n duy nh\u1ea5t th\u00f4ng qua c\u00e1c container ch\u00e8n ph\u1ee5 thu\u1ed9c. Nh\u1eefng c\u00f4ng c\u1ee5 n\u00e0y l\u00e0m m\u1edd \u0111i \u0111\u1ed9 ph\u1ee9c t\u1ea1p c\u1ee7a an to\u00e0n \u0111a lu\u1ed3ng v\u00e0 qu\u1ea3n l\u00fd v\u00f2ng \u0111\u1eddi, gi\u00fap c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n t\u1eadp trung v\u00e0o logic kinh doanh. Vi\u1ec7c t\u1eadn d\u1ee5ng c\u00e1c c\u00f4ng c\u1ee5 n\u00e0y th\u01b0\u1eddng an to\u00e0n h\u01a1n so v\u1edbi vi\u1ec7c tri\u1ec3n khai m\u1ed9t Singleton t\u00f9y ch\u1ec9nh.<\/p>\n

                  Cu\u1ed1i c\u00f9ng, s\u1ee9c kh\u1ecfe c\u1ee7a m\u1ed9t h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m ph\u1ee5 thu\u1ed9c v\u00e0o kh\u1ea3 n\u0103ng b\u1ea3o tr\u00ec c\u1ee7a n\u00f3. M\u00e3 ngu\u1ed3n ph\u1ee5 thu\u1ed9c nhi\u1ec1u v\u00e0o tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c s\u1ebd kh\u00f3 b\u1ea3o tr\u00ec, t\u00e1i c\u1ea5u tr\u00fac v\u00e0 m\u1edf r\u1ed9ng. B\u1eb1ng c\u00e1ch \u01b0u ti\u00ean c\u00e1c ph\u1ee5 thu\u1ed9c r\u00f5 r\u00e0ng v\u00e0 tr\u1ea1ng th\u00e1i \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t, b\u1ea1n x\u00e2y d\u1ef1ng \u0111\u01b0\u1ee3c c\u00e1c h\u1ec7 th\u1ed1ng b\u1ec1n b\u1ec9 v\u00e0 linh ho\u1ea1t tr\u01b0\u1edbc s\u1ef1 thay \u0111\u1ed5i.<\/p>\n","protected":false},"excerpt":{"rendered":"

                  C\u00e1c m\u1eabu thi\u1ebft k\u1ebf \u0111\u00f3ng vai tr\u00f2 n\u1ec1n t\u1ea3ng cho ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m v\u1eefng ch\u1eafc. Trong s\u1ed1 c\u00e1c m\u1eabu t\u1ea1o l\u1eadp, m\u1eabu Singleton th\u01b0\u1eddng \u0111\u01b0\u1ee3c th\u1ea3o lu\u1eadn nhi\u1ec1u, nh\u01b0ng…<\/p>\n","protected":false},"author":1,"featured_media":3627,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_yoast_wpseo_title":"H\u01b0\u1edbng d\u1eabn M\u1eabu Singleton Kh\u00f4ng G\u00e2y V\u1ea5n \u0110\u1ec1 Tr\u1ea1ng Th\u00e1i To\u00e0n C\u1ee5c \ud83d\udee1\ufe0f","_yoast_wpseo_metadesc":"H\u1ecdc c\u00e1ch tri\u1ec3n khai m\u1eabu Singleton m\u1ed9t c\u00e1ch an to\u00e0n. Tr\u00e1nh c\u00e1c b\u1eaby tr\u1ea1ng th\u00e1i to\u00e0n c\u1ee5c, qu\u1ea3n l\u00fd an to\u00e0n \u0111a lu\u1ed3ng v\u00e0 kh\u00e1m ph\u00e1 c\u00e1c gi\u1ea3i ph\u00e1p thay th\u1ebf ch\u00e8n ph\u1ee5 thu\u1ed9c. \u2699\ufe0f","fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[105],"tags":[103,104],"class_list":["post-3626","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-object-oriented-analysis-and-design","tag-academic","tag-object-oriented-analysis-and-design"],"yoast_head":"\nH\u01b0\u1edbng d\u1eabn M\u1eabu Singleton Kh\u00f4ng G\u00e2y V\u1ea5n \u0110\u1ec1 Tr\u1ea1ng Th\u00e1i To\u00e0n C\u1ee5c \ud83d\udee1\ufe0f<\/title>\n<meta name=\"description\" content=\"H\u1ecdc c\u00e1ch tri\u1ec3n khai m\u1eabu Singleton m\u1ed9t c\u00e1ch an to\u00e0n. 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