{"id":476236,"date":"2023-08-09T07:26:52","date_gmt":"2023-08-09T07:26:52","guid":{"rendered":""},"modified":"2023-09-05T11:12:18","modified_gmt":"2023-09-05T11:12:18","slug":"class","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/class\/","title":{"rendered":"L\u1edbp h\u1ecdc"},"content":{"rendered":"<p>L\u1edbp, trong l\u0129nh v\u1ef1c l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOP), l\u00e0 m\u1ed9t ph\u1ea7n kh\u00f4ng th\u1ec3 thi\u1ebfu trong vi\u1ec7c thi\u1ebft k\u1ebf v\u00e0 ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m. M\u1ed9t l\u1edbp ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t b\u1ea3n thi\u1ebft k\u1ebf chi ti\u1ebft \u0111\u1ec3 t\u1ea1o c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng (m\u1ed9t c\u1ea5u tr\u00fac d\u1eef li\u1ec7u c\u1ee5 th\u1ec3), cung c\u1ea5p c\u00e1c gi\u00e1 tr\u1ecb ban \u0111\u1ea7u cho tr\u1ea1ng th\u00e1i (c\u00e1c bi\u1ebfn ho\u1eb7c thu\u1ed9c t\u00ednh th\u00e0nh vi\u00ean) v\u00e0 tri\u1ec3n khai h\u00e0nh vi (c\u00e1c h\u00e0m ho\u1eb7c ph\u01b0\u01a1ng th\u1ee9c th\u00e0nh vi\u00ean).<\/p>\n<h2>Ngu\u1ed3n g\u1ed1c v\u00e0 l\u1ecbch s\u1eed c\u1ee7a l\u1edbp<\/h2>\n<p>Kh\u00e1i ni\u1ec7m l\u1edbp trong l\u1eadp tr\u00ecnh b\u1eaft ngu\u1ed3n t\u1eeb vi\u1ec7c gi\u1edbi thi\u1ec7u l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOP). \u00dd t\u01b0\u1edfng v\u1ec1 c\u00e1c l\u1edbp h\u1ecdc l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n trong Simula 67, m\u1ed9t ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf v\u00e0o kho\u1ea3ng n\u0103m 1965 b\u1edfi Ole-Johan Dahl v\u00e0 Kristen Nygaard. Kh\u00e1i ni\u1ec7m l\u1edbp n\u00e0y sau \u0111\u00f3 \u0111\u01b0\u1ee3c t\u00edch h\u1ee3p v\u00e0o c\u00e1c ng\u00f4n ng\u1eef c\u00f3 \u1ea3nh h\u01b0\u1edfng kh\u00e1c nh\u01b0 Smalltalk, C++ v\u00e0 Java, \u0111\u1ecbnh h\u00ecnh b\u1ed1i c\u1ea3nh c\u1ee7a c\u00e1c m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh hi\u1ec7n \u0111\u1ea1i.<\/p>\n<h2>M\u1ed9t c\u00e1i nh\u00ecn s\u00e2u h\u01a1n v\u1ec1 l\u1edbp h\u1ecdc<\/h2>\n<p>C\u00e1c l\u1edbp l\u00e0 n\u1ec1n t\u1ea3ng c\u1ee7a l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng. H\u1ecd g\u1ed9p c\u00e1c bi\u1ebfn v\u00e0 h\u00e0m th\u00e0nh m\u1ed9t th\u1ef1c th\u1ec3. M\u1ed9t l\u1edbp x\u00e1c \u0111\u1ecbnh c\u00e1c lo\u1ea1i d\u1eef li\u1ec7u v\u00e0 c\u00e1c thao t\u00e1c c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n tr\u00ean d\u1eef li\u1ec7u \u0111\u00f3. M\u1ed9t l\u1edbp \u0111\u00f3ng g\u00f3i d\u1eef li\u1ec7u cho \u0111\u1ed1i t\u01b0\u1ee3ng. B\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng c\u00e1c l\u1edbp, nh\u00e0 ph\u00e1t tri\u1ec3n c\u00f3 th\u1ec3 t\u1ea1o c\u00e1c ki\u1ec3u m\u1edbi ph\u00f9 h\u1ee3p h\u01a1n v\u1edbi c\u00e1c kh\u00e1i ni\u1ec7m m\u00e0 h\u1ecd \u0111ang m\u00f4 h\u00ecnh h\u00f3a ch\u1eb7t ch\u1ebd h\u01a1n.<\/p>\n<p>L\u00e0 m\u1ed9t kh\u1ed1i x\u00e2y d\u1ef1ng c\u01a1 b\u1ea3n c\u1ee7a c\u00e1c \u1ee9ng d\u1ee5ng ph\u1ea7n m\u1ec1m, m\u1ed9t l\u1edbp ch\u1ee9a hai th\u00e0nh ph\u1ea7n ch\u00ednh:<\/p>\n<ol>\n<li><strong>L\u0129nh v\u1ef1c<\/strong>: \u0110\u00e2y l\u00e0 c\u00e1c bi\u1ebfn gi\u1eef tr\u1ea1ng th\u00e1i c\u1ee7a \u0111\u1ed1i t\u01b0\u1ee3ng.<\/li>\n<li><strong>ph\u01b0\u01a1ng ph\u00e1p<\/strong>: \u0110\u00e2y l\u00e0 c\u00e1c h\u00e0m x\u00e1c \u0111\u1ecbnh nh\u1eefng g\u00ec \u0111\u1ed1i t\u01b0\u1ee3ng c\u00f3 th\u1ec3 l\u00e0m.<\/li>\n<\/ol>\n<p>Theo ngh\u0129a th\u1ef1c t\u1ebf, c\u00e1c l\u1edbp cho ph\u00e9p \u0111\u00f3ng g\u00f3i d\u1eef li\u1ec7u v\u00e0 ph\u01b0\u01a1ng th\u1ee9c, k\u1ebf th\u1eeba c\u00e1c \u0111\u1eb7c \u0111i\u1ec3m t\u1eeb c\u00e1c l\u1edbp kh\u00e1c v\u00e0 t\u1ea1o ra c\u00e1c th\u1ec3 hi\u1ec7n \u0111\u1ed1i t\u01b0\u1ee3ng, bi\u1ec3u hi\u1ec7n c\u1ee5 th\u1ec3 c\u1ee7a l\u1edbp.<\/p>\n<h2>C\u1ea5u tr\u00fac b\u00ean trong v\u00e0 ho\u1ea1t \u0111\u1ed9ng c\u1ee7a l\u1edbp<\/h2>\n<p>C\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a m\u1ed9t l\u1edbp th\u01b0\u1eddng ch\u1ee9a s\u1ef1 k\u1ebft h\u1ee3p c\u1ee7a c\u00e1c tr\u01b0\u1eddng (ph\u1ea7n t\u1eed d\u1eef li\u1ec7u) v\u00e0 c\u00e1c ph\u01b0\u01a1ng th\u1ee9c. C\u00e1c tr\u01b0\u1eddng gi\u1eef tr\u1ea1ng th\u00e1i c\u1ee7a m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng, trong khi c\u00e1c ph\u01b0\u01a1ng th\u1ee9c x\u00e1c \u0111\u1ecbnh s\u1ef1 t\u01b0\u01a1ng t\u00e1c c\u1ee7a n\u00f3 v\u1edbi th\u1ebf gi\u1edbi b\u00ean ngo\u00e0i. \u0110\u00e2y l\u00e0 c\u1ea5u tr\u00fac \u0111\u01a1n gi\u1ea3n c\u1ee7a m\u1ed9t l\u1edbp trong Java:<\/p>\n<pre><div class=\"bg-black rounded-md mb-4\"><div class=\"flex items-center relative text-gray-200 bg-gray-800 px-4 py-2 text-xs font-sans justify-between rounded-t-md\"><span>java<\/span><button class=\"flex ml-auto gap-2\"><svg stroke=\"currentColor\" fill=\"none\" stroke-width=\"2\" viewbox=\"0 0 24 24\" stroke-linecap=\"round\" stroke-linejoin=\"round\" class=\"h-4 w-4\" height=\"1em\" width=\"1em\" ><path d=\"M16 4h2a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2h2\"><\/path><rect x=\"8\" y=\"2\" width=\"8\" height=\"4\" rx=\"1\" ry=\"1\"><\/rect><\/svg>Sao ch\u00e9p m\u00e3<\/button><\/div><div class=\"p-4 overflow-y-auto\"><code class=\"!whitespace-pre hljs language-java\" data-no-translation=\"\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">MyClass<\/span> {\n   <span class=\"hljs-comment\">\/\/ field (class variable)<\/span>\n   <span class=\"hljs-type\">int<\/span> myVariable;\n\n   <span class=\"hljs-comment\">\/\/ method<\/span>\n   <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title function_\">myMethod<\/span><span class=\"hljs-params\">()<\/span> {\n      <span class=\"hljs-comment\">\/\/ code<\/span>\n   }\n}\n<\/code><\/div><\/div><\/pre>\n<p>Trong v\u00ed d\u1ee5 n\u00e0y, <code data-no-translation=\"\">myVariable<\/code> l\u00e0 m\u1ed9t tr\u01b0\u1eddng c\u00f3 th\u1ec3 ch\u1ee9a d\u1eef li\u1ec7u v\u00e0 <code data-no-translation=\"\">myMethod()<\/code> l\u00e0 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p th\u1ef1c hi\u1ec7n m\u1ed9t ho\u1ea1t \u0111\u1ed9ng nh\u1ea5t \u0111\u1ecbnh. L\u1edbp <code data-no-translation=\"\">MyClass<\/code> c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c kh\u1edfi t\u1ea1o d\u01b0\u1edbi d\u1ea1ng c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng, m\u1ed7i \u0111\u1ed1i t\u01b0\u1ee3ng s\u1ebd c\u00f3 c\u00e1i ri\u00eang c\u1ee7a n\u00f3 <code data-no-translation=\"\">myVariable<\/code> c\u00e1nh \u0111\u1ed3ng.<\/p>\n<h2>C\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a l\u1edbp<\/h2>\n<p>C\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a c\u00e1c l\u1edbp trong l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng l\u00e0:<\/p>\n<ol>\n<li><strong>\u0110\u00f3ng g\u00f3i<\/strong>: Vi\u1ec7c tri\u1ec3n khai c\u1ee7a l\u1edbp \u0111\u01b0\u1ee3c \u0111\u00f3ng g\u00f3i v\u00e0 \u1ea9n kh\u1ecfi c\u00e1c l\u1edbp kh\u00e1c. N\u00f3 ch\u1ec9 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c truy c\u1eadp th\u00f4ng qua c\u00e1c ph\u01b0\u01a1ng th\u1ee9c.<\/li>\n<li><strong>Tr\u1eebu t\u01b0\u1ee3ng<\/strong>: M\u1ed9t l\u1edbp \u0111\u00f3ng g\u00f3i c\u00e1c d\u1eef li\u1ec7u v\u00e0 ph\u01b0\u01a1ng th\u1ee9c li\u00ean quan c\u1ea7n thi\u1ebft cho c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng c\u1ee7a n\u00f3, cung c\u1ea5p m\u1ed9t giao di\u1ec7n \u0111\u01a1n gi\u1ea3n v\u00e0 \u1ea9n c\u00e1c chi ti\u1ebft tri\u1ec3n khai.<\/li>\n<li><strong>Di s\u1ea3n<\/strong>: C\u00e1c l\u1edbp c\u00f3 th\u1ec3 k\u1ebf th\u1eeba c\u00e1c \u0111\u1eb7c \u0111i\u1ec3m (tr\u01b0\u1eddng v\u00e0 ph\u01b0\u01a1ng th\u1ee9c) t\u1eeb c\u00e1c l\u1edbp kh\u00e1c.<\/li>\n<li><strong>\u0110a h\u00ecnh<\/strong>: C\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng c\u1ee7a m\u1ed9t l\u1edbp c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c x\u1eed l\u00fd gi\u1ed1ng nh\u01b0 c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng c\u1ee7a si\u00eau l\u1edbp c\u1ee7a ch\u00fang, cho ph\u00e9p t\u00ednh linh ho\u1ea1t trong m\u00e3 h\u00f3a.<\/li>\n<\/ol>\n<h2>C\u00e1c lo\u1ea1i l\u1edbp h\u1ecdc<\/h2>\n<p>C\u00e1c l\u1edbp h\u1ecdc c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i th\u00e0nh c\u00e1c lo\u1ea1i kh\u00e1c nhau d\u1ef1a tr\u00ean \u0111\u1eb7c \u0111i\u1ec3m v\u00e0 h\u00e0nh vi c\u1ee7a ch\u00fang. \u0110\u00e2y l\u00e0 b\u1ea3ng t\u00f3m t\u1eaft c\u00e1c lo\u1ea1i n\u00e0y:<\/p>\n<table>\n<thead>\n<tr>\n<th>Lo\u1ea1i l\u1edbp h\u1ecdc<\/th>\n<th>S\u1ef1 mi\u00eau t\u1ea3<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>L\u1edbp b\u00ea t\u00f4ng<\/td>\n<td>Lo\u1ea1i l\u1edbp m\u1eb7c \u0111\u1ecbnh, c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c kh\u1edfi t\u1ea1o<\/td>\n<\/tr>\n<tr>\n<td>L\u1edbp tr\u1eebu t\u01b0\u1ee3ng<\/td>\n<td>Kh\u00f4ng th\u1ec3 kh\u1edfi t\u1ea1o \u0111\u01b0\u1ee3c, th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng l\u00e0m l\u1edbp c\u01a1 s\u1edf<\/td>\n<\/tr>\n<tr>\n<td>L\u1edbp l\u1ed3ng nhau<\/td>\n<td>M\u1ed9t l\u1edbp \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a trong m\u1ed9t l\u1edbp kh\u00e1c<\/td>\n<\/tr>\n<tr>\n<td>L\u1edbp \u1ea9n danh<\/td>\n<td>M\u1ed9t l\u1edbp kh\u00f4ng c\u00f3 t\u00ean, th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong x\u1eed l\u00fd s\u1ef1 ki\u1ec7n GUI<\/td>\n<\/tr>\n<tr>\n<td>L\u1edbp cu\u1ed1i c\u00f9ng<\/td>\n<td>M\u1ed9t l\u1edbp kh\u00f4ng th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n l\u1edbp<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>S\u1eed d\u1ee5ng l\u1edbp: V\u1ea5n \u0111\u1ec1 v\u00e0 gi\u1ea3i ph\u00e1p<\/h2>\n<p>M\u1ed9t v\u1ea5n \u0111\u1ec1 th\u01b0\u1eddng g\u1eb7p khi s\u1eed d\u1ee5ng c\u00e1c l\u1edbp l\u00e0 thi\u1ebft k\u1ebf kh\u00f4ng ph\u00f9 h\u1ee3p, d\u1eabn \u0111\u1ebfn c\u00e1c v\u1ea5n \u0111\u1ec1 nh\u01b0 kh\u00f3 b\u1ea3o tr\u00ec v\u00e0 s\u1eeda \u0111\u1ed5i m\u00e3. Gi\u1ea3i ph\u00e1p l\u00e0 tu\u00e2n theo c\u00e1c nguy\u00ean t\u1eafc thi\u1ebft k\u1ebf nh\u01b0 SOLID (Tr\u00e1ch nhi\u1ec7m duy nh\u1ea5t, \u0110\u00f3ng m\u1edf, Thay th\u1ebf Liskov, Ph\u00e2n chia giao di\u1ec7n, \u0110\u1ea3o ng\u01b0\u1ee3c ph\u1ee5 thu\u1ed9c).<\/p>\n<p>M\u1ed9t v\u1ea5n \u0111\u1ec1 kh\u00e1c n\u1ea3y sinh khi c\u00e1c l\u1edbp qu\u00e1 l\u1edbn ho\u1eb7c ph\u1ee9c t\u1ea1p, \u0111i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 l\u00e0m cho ch\u01b0\u01a1ng tr\u00ecnh kh\u00f3 hi\u1ec3u ho\u1eb7c kh\u00f3 g\u1ee1 l\u1ed7i. Gi\u1ea3i ph\u00e1p cho v\u1ea5n \u0111\u1ec1 n\u00e0y l\u00e0 t\u00e1i c\u1ea5u tr\u00fac, bao g\u1ed3m vi\u1ec7c chia l\u1edbp th\u00e0nh c\u00e1c th\u00e0nh ph\u1ea7n nh\u1ecf h\u01a1n, d\u1ec5 qu\u1ea3n l\u00fd h\u01a1n.<\/p>\n<h2>So s\u00e1nh v\u1edbi c\u00e1c \u0111i\u1ec1u kho\u1ea3n t\u01b0\u01a1ng t\u1ef1<\/h2>\n<p>M\u1ed9t l\u1edbp \u0111\u00f4i khi b\u1ecb nh\u1ea7m l\u1eabn v\u1edbi c\u00e1c thu\u1eadt ng\u1eef kh\u00e1c nh\u01b0 \u0111\u1ed1i t\u01b0\u1ee3ng, c\u1ea5u tr\u00fac v\u00e0 ki\u1ec3u. \u0110\u00e2y l\u00e0 m\u1ed9t so s\u00e1nh ng\u1eafn g\u1ecdn:<\/p>\n<table>\n<thead>\n<tr>\n<th>Thu\u1eadt ng\u1eef<\/th>\n<th>S\u1ef1 mi\u00eau t\u1ea3<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>S\u1ef1 v\u1eadt<\/td>\n<td>M\u1ed9t th\u1ec3 hi\u1ec7n c\u1ee7a m\u1ed9t l\u1edbp. N\u1ebfu m\u1ed9t l\u1edbp gi\u1ed1ng nh\u01b0 m\u1ed9t b\u1ea3n thi\u1ebft k\u1ebf th\u00ec m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng gi\u1ed1ng nh\u01b0 m\u1ed9t ng\u00f4i nh\u00e0 \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng t\u1eeb b\u1ea3n thi\u1ebft k\u1ebf \u0111\u00f3<\/td>\n<\/tr>\n<tr>\n<td>K\u1ebft c\u1ea5u<\/td>\n<td>T\u01b0\u01a1ng t\u1ef1 nh\u01b0 m\u1ed9t l\u1edbp, nh\u01b0ng th\u01b0\u1eddng thi\u1ebfu m\u1ed9t s\u1ed1 t\u00ednh n\u0103ng OOP nh\u01b0 ph\u01b0\u01a1ng th\u1ee9c (t\u00f9y theo ng\u00f4n ng\u1eef). \u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng ch\u1ee7 y\u1ebfu trong l\u1eadp tr\u00ecnh th\u1ee7 t\u1ee5c<\/td>\n<\/tr>\n<tr>\n<td>Ki\u1ec3u<\/td>\n<td>M\u1ed9t kh\u00e1i ni\u1ec7m r\u1ed9ng h\u01a1n bao g\u1ed3m c\u00e1c l\u1edbp, nguy\u00ean th\u1ee7y, m\u1ea3ng v\u00e0 giao di\u1ec7n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Quan \u0111i\u1ec3m t\u01b0\u01a1ng lai v\u00e0 c\u00f4ng ngh\u1ec7 li\u00ean quan \u0111\u1ebfn l\u1edbp h\u1ecdc<\/h2>\n<p>L\u00e0 n\u1ec1n t\u1ea3ng c\u1ee7a l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng, kh\u00e1i ni\u1ec7m v\u1ec1 l\u1edbp s\u1ebd ti\u1ebfp t\u1ee5c ph\u00e1t tri\u1ec3n c\u00f9ng v\u1edbi s\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a c\u00e1c ph\u01b0\u01a1ng ph\u00e1p ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m. C\u00e1c kh\u00e1i ni\u1ec7m nh\u01b0 metaclasses (m\u1ed9t l\u1edbp c\u1ee7a m\u1ed9t l\u1edbp), generics (c\u00e1c l\u1edbp \u0111\u01b0\u1ee3c tham s\u1ed1 h\u00f3a) v\u00e0 c\u00e1c th\u00e0nh ph\u1ea7n ph\u1ea7n m\u1ec1m (nh\u00f3m c\u00e1c l\u1edbp) \u0111ang \u0111\u01b0\u1ee3c nghi\u00ean c\u1ee9u v\u00e0 ph\u00e1t tri\u1ec3n th\u00eam.<\/p>\n<h2>M\u00e1y ch\u1ee7 proxy v\u00e0 l\u1edbp<\/h2>\n<p>Trong b\u1ed1i c\u1ea3nh m\u00e1y ch\u1ee7 proxy, gi\u1ed1ng nh\u01b0 c\u00e1c m\u00e1y ch\u1ee7 proxy \u0111\u01b0\u1ee3c cung c\u1ea5p b\u1edfi OneProxy, c\u00e1c l\u1edbp c\u00f3 th\u1ec3 \u0111\u00f3ng m\u1ed9t vai tr\u00f2 quan tr\u1ecdng trong vi\u1ec7c ph\u00e1t tri\u1ec3n v\u00e0 qu\u1ea3n l\u00fd c\u00e1c h\u1ec7 th\u1ed1ng n\u00e0y. V\u00ed d\u1ee5: l\u1edbp &#039;ProxyServer&#039; c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1c ph\u01b0\u01a1ng th\u1ee9c x\u1eed l\u00fd y\u00eau c\u1ea7u c\u1ee7a m\u00e1y kh\u00e1ch, chuy\u1ec3n ti\u1ebfp y\u00eau c\u1ea7u v\u00e0 n\u1ed9i dung b\u1ed9 nh\u1edb \u0111\u1ec7m. Vi\u1ec7c hi\u1ec3u v\u00e0 tri\u1ec3n khai \u0111\u00fang c\u00e1c l\u1edbp c\u00f3 th\u1ec3 gi\u00fap c\u1ea3i thi\u1ec7n hi\u1ec7u qu\u1ea3, kh\u1ea3 n\u0103ng b\u1ea3o tr\u00ec v\u00e0 kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng c\u1ee7a h\u1ec7 th\u1ed1ng m\u00e1y ch\u1ee7 proxy.<\/p>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<ol>\n<li><a href=\"https:\/\/docs.oracle.com\/javase\/tutorial\/java\/concepts\/class.html\" target=\"_new\" rel=\"noopener nofollow\">T\u00e0i li\u1ec7u Oracle Java \u2013 L\u1edbp<\/a><\/li>\n<li><a href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Web\/JavaScript\/Reference\/Classes\" target=\"_new\" rel=\"noopener nofollow\">M\u1ea1ng l\u01b0\u1edbi nh\u00e0 ph\u00e1t tri\u1ec3n Mozilla \u2013 C\u00e1c l\u1edbp h\u1ecdc<\/a><\/li>\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Class_(computer_programming)\" target=\"_new\" rel=\"noopener nofollow\">Wikipedia \u2013 L\u1edbp h\u1ecdc (l\u1eadp tr\u00ecnh m\u00e1y t\u00ednh)<\/a><\/li>\n<\/ol>","protected":false},"featured_media":0,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-476236","wiki","type-wiki","status-publish","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Class in Computer Science and Proxy Servers<\/mark>","faq_items":[{"question":"What is a class in computer science?","answer":"<p>In the field of object-oriented programming (OOP), a class is a blueprint for creating objects. It provides initial values for state (member variables or attributes) and implementations of behavior (member functions or methods).<\/p>"},{"question":"What is the origin and history of the class concept in programming?","answer":"<p>The concept of a class in programming originated with the introduction of object-oriented programming (OOP). The idea of classes was first developed in Simula 67, a programming language designed around 1965 by Ole-Johan Dahl and Kristen Nygaard. This class concept was later integrated into other influential languages like Smalltalk, C++, and Java.<\/p>"},{"question":"How does a class work in programming?","answer":"<p>A class generally contains a combination of fields (data elements) and methods. The fields hold the state of an object, while the methods define its interaction with the outside world.<\/p>"},{"question":"What are the key features of classes in programming?","answer":"<p>The key features of classes in object-oriented programming are encapsulation, abstraction, inheritance, and polymorphism.<\/p>"},{"question":"What types of classes exist in programming?","answer":"<p>Classes can be categorized into different types based on their characteristics and behaviors. Some types of classes include Concrete Class, Abstract Class, Nested Class, Anonymous Class, and Final Class.<\/p>"},{"question":"What problems might arise when using classes and how can they be solved?","answer":"<p>One common problem when using classes is improper design, leading to issues such as difficulty in code maintenance and modification. This can be solved by following design principles like SOLID. Another problem arises when classes are excessively large or complex, which can be solved by refactoring, breaking the class down into smaller, more manageable components.<\/p>"},{"question":"How can classes be used in the context of proxy servers?","answer":"<p>In the context of proxy servers, like those provided by OneProxy, classes can play a critical role in developing and managing these systems. A 'ProxyServer' class could define methods for handling client requests, forwarding requests, and caching content.<\/p>"},{"question":"What are some future perspectives and technologies related to classes?","answer":"<p>As a cornerstone of object-oriented programming, the concept of a class will continue to evolve with the progression of software development methodologies. Concepts like metaclasses (a class of a class), generics (parameterized classes), and software components (group of classes) are being researched and developed further.<\/p>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/476236","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki"}],"about":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/types\/wiki"}],"version-history":[{"count":0,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/476236\/revisions"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=476236"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}