{"id":671,"date":"2025-02-13T21:25:22","date_gmt":"2025-02-13T13:25:22","guid":{"rendered":"http:\/\/www.cmd137blog.top\/?p=671"},"modified":"2025-02-13T21:25:24","modified_gmt":"2025-02-13T13:25:24","slug":"java-%e6%b3%a8%e8%a7%a3-annotation","status":"publish","type":"post","link":"http:\/\/www.cmd137blog.top\/?p=671","title":{"rendered":"JAVA-\u6ce8\u89e3 Annotation"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">\u4e00\u3001Java \u6ce8\u89e3\u57fa\u7840<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e00\uff09\u4ec0\u4e48\u662f\u6ce8\u89e3<\/h3>\n\n\n\n<p>\u6ce8\u89e3\u662f\u4e00\u79cd\u7279\u6b8a\u7684\u6807\u8bb0\uff0c\u5b83\u53ef\u4ee5\u88ab\u6dfb\u52a0\u5230\u5305\u3001\u7c7b\u3001\u65b9\u6cd5\u3001\u5b57\u6bb5\u7b49\u7a0b\u5e8f\u5143\u7d20\u4e0a\uff0c\u7528\u4e8e\u4e3a\u8fd9\u4e9b\u5143\u7d20\u6dfb\u52a0\u989d\u5916\u7684\u4fe1\u606f\u3002\u8fd9\u4e9b\u4fe1\u606f\u53ef\u4ee5\u5728\u7f16\u8bd1\u671f\u3001\u8fd0\u884c\u671f\u88ab\u8bfb\u53d6\u548c\u5904\u7406\uff0c\u4ece\u800c\u5b9e\u73b0\u5404\u79cd\u529f\u80fd\uff0c\u6bd4\u5982\u4ee3\u7801\u751f\u6210\u3001\u914d\u7f6e\u7ba1\u7406\u3001\u6d4b\u8bd5\u6846\u67b6\u652f\u6301\u7b49\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e8c\uff09\u5185\u7f6e\u6ce8\u89e3<\/h3>\n\n\n\n<p>Java \u63d0\u4f9b\u4e86\u4e00\u4e9b\u5185\u7f6e\u6ce8\u89e3\uff0c\u5e38\u89c1\u7684\u6709\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>@Override\uff1a\u7528\u4e8e\u6807\u8bc6\u65b9\u6cd5\u662f\u91cd\u5199\u7236\u7c7b\u7684\u65b9\u6cd5\uff0c\u7f16\u8bd1\u5668\u4f1a\u8fdb\u884c\u68c0\u67e5\uff0c\u786e\u4fdd\u65b9\u6cd5\u7b7e\u540d\u6b63\u786e\u3002<\/li>\n\n\n\n<li>@Deprecated\uff1a\u8868\u793a\u8be5\u5143\u7d20\u5df2\u8fc7\u65f6\uff0c\u4f7f\u7528\u65f6\u7f16\u8bd1\u5668\u4f1a\u7ed9\u51fa\u8b66\u544a\u3002<\/li>\n\n\n\n<li>@SuppressWarnings\uff1a\u6291\u5236\u7f16\u8bd1\u5668\u8b66\u544a\uff0c\u4f8b\u5982@SuppressWarnings(&#8220;unchecked&#8221;)\u53ef\u4ee5\u6291\u5236\u7c7b\u578b\u8f6c\u6362\u65f6\u7684 unchecked \u8b66\u544a\u3002<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e8c\u3001\u5143\u6ce8\u89e3<\/h2>\n\n\n\n<p>\u5143\u6ce8\u89e3\u662f\u7528\u4e8e<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-purple-color\">\u4fee\u9970\u6ce8\u89e3\u7684\u6ce8\u89e3<\/mark><\/strong>\uff0c\u5b83\u4e3a\u6ce8\u89e3\u63d0\u4f9b\u4e86\u66f4\u591a\u7684\u5143\u6570\u636e\u4fe1\u606f\uff0c\u4ece\u800c\u63a7\u5236\u6ce8\u89e3\u7684\u884c\u4e3a\u548c\u4f7f\u7528\u65b9\u5f0f\u3002\u5728 Java \u4e2d\uff0c\u4e3b\u8981\u6709\u4ee5\u4e0b\u51e0\u79cd\u5143\u6ce8\u89e3\uff1a<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e00\uff09@Retention<\/h3>\n\n\n\n<p>@Retention \u5143\u6ce8\u89e3\u7528\u4e8e\u6307\u5b9a\u88ab\u4fee\u9970\u6ce8\u89e3\u7684\u4fdd\u7559\u7b56\u7565\uff0c\u5373\u8be5\u6ce8\u89e3\u5728\u4ec0\u4e48\u9636\u6bb5\u5b58\u5728\u3002RetentionPolicy \u6709\u4e09\u4e2a\u53d6\u503c\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>RetentionPolicy.SOURCE\uff1a\u6ce8\u89e3\u53ea\u5728\u6e90\u4ee3\u7801\u4e2d\u5b58\u5728\uff0c\u7f16\u8bd1\u65f6\u4f1a\u88ab\u4e22\u5f03\u3002<\/li>\n\n\n\n<li>RetentionPolicy.CLASS\uff1a\u6ce8\u89e3\u5728\u7f16\u8bd1\u540e\u7684\u5b57\u8282\u7801\u4e2d\u5b58\u5728\uff0c\u4f46\u8fd0\u884c\u65f6 JVM \u4e0d\u4f1a\u8bfb\u53d6\uff0c\u8fd9\u662f\u9ed8\u8ba4\u503c\u3002<\/li>\n\n\n\n<li>RetentionPolicy.RUNTIME\uff1a\u6ce8\u89e3\u5728\u8fd0\u884c\u65f6\u4ecd\u7136\u5b58\u5728\uff0cJVM \u53ef\u4ee5\u8bfb\u53d6\uff0c\u53ef\u4ee5\u901a\u8fc7\u53cd\u5c04\u83b7\u53d6\u6ce8\u89e3\u4fe1\u606f\u5e76\u8fdb\u884c\u5904\u7406\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4f8b\u5982\uff0c\u5b9a\u4e49\u4e00\u4e2a\u8fd0\u884c\u65f6\u4fdd\u7559\u7684\u6ce8\u89e3\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;@Retention(RetentionPolicy.RUNTIME)public @interface MyAnnotation {    String value() default \"\";}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e8c\uff09@Target<\/h3>\n\n\n\n<p>@Target \u5143\u6ce8\u89e3\u7528\u4e8e\u6307\u5b9a\u88ab\u4fee\u9970\u6ce8\u89e3\u53ef\u4ee5\u5e94\u7528\u5728\u54ea\u4e9b\u7a0b\u5e8f\u5143\u7d20\u4e0a\u3002ElementType \u6709\u591a\u4e2a\u53d6\u503c\uff0c\u5e38\u89c1\u7684\u6709\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>ElementType.TYPE\uff1a\u53ef\u4ee5\u5e94\u7528\u4e8e\u7c7b\u3001\u63a5\u53e3\u3001\u679a\u4e3e\u7b49\u7c7b\u578b\u3002<\/li>\n\n\n\n<li>ElementType.METHOD\uff1a\u53ef\u4ee5\u5e94\u7528\u4e8e\u65b9\u6cd5\u3002<\/li>\n\n\n\n<li>ElementType.FIELD\uff1a\u53ef\u4ee5\u5e94\u7528\u4e8e\u5b57\u6bb5\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4f8b\u5982\uff0c\u5c06\u6ce8\u89e3\u9650\u5236\u4e3a\u53ea\u80fd\u5e94\u7528\u4e8e\u65b9\u6cd5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>import java.lang.annotation.ElementType;import java.lang.annotation.Target;@Target(ElementType.METHOD)public @interface MyAnnotation {    String value() default \"\";}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e09\uff09@Documented<\/h3>\n\n\n\n<p>@Documented \u5143\u6ce8\u89e3\u8868\u793a\u88ab\u4fee\u9970\u7684\u6ce8\u89e3\u4f1a\u88ab Javadoc \u5de5\u5177\u8bb0\u5f55\u3002\u5982\u679c\u4e00\u4e2a\u6ce8\u89e3\u88ab @Documented \u4fee\u9970\uff0c\u90a3\u4e48\u5728\u751f\u6210 API \u6587\u6863\u65f6\uff0c\u8be5\u6ce8\u89e3\u4e5f\u4f1a\u88ab\u5305\u542b\u5728\u6587\u6863\u4e2d\uff0c\u65b9\u4fbf\u5176\u4ed6\u5f00\u53d1\u8005\u4e86\u89e3\u4f7f\u7528\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u56db\uff09@Inherited<\/h3>\n\n\n\n<p>@Inherited \u5143\u6ce8\u89e3\u8868\u793a\u88ab\u4fee\u9970\u7684\u6ce8\u89e3\u5177\u6709\u7ee7\u627f\u6027\u3002\u5982\u679c\u4e00\u4e2a\u7c7b\u4f7f\u7528\u4e86\u88ab @Inherited \u4fee\u9970\u7684\u6ce8\u89e3\uff0c\u90a3\u4e48\u5b83\u7684\u5b50\u7c7b\u4e5f\u4f1a\u81ea\u52a8\u7ee7\u627f\u8be5\u6ce8\u89e3\u3002\u4e0d\u8fc7\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u8fd9\u4e2a\u7ee7\u627f\u53ea\u9488\u5bf9\u7c7b\uff0c\u5bf9\u4e8e\u63a5\u53e3\u548c\u65b9\u6cd5\u7b49\u5e76\u4e0d\u9002\u7528\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e94\uff09@Repeatable<\/h3>\n\n\n\n<p>@Repeatable \u5143\u6ce8\u89e3\u5141\u8bb8\u540c\u4e00\u4e2a\u6ce8\u89e3\u5728\u540c\u4e00\u4e2a\u7a0b\u5e8f\u5143\u7d20\u4e0a\u88ab\u591a\u6b21\u4f7f\u7528\u3002\u5728 Java 8 \u4e4b\u524d\uff0c\u4e00\u4e2a\u7a0b\u5e8f\u5143\u7d20\u4e0a\u53ea\u80fd\u4f7f\u7528\u4e00\u6b21\u76f8\u540c\u7684\u6ce8\u89e3\u3002\u6709\u4e86 @Repeatable \u540e\uff0c\u5f00\u53d1\u8005\u53ef\u4ee5\u66f4\u7075\u6d3b\u5730\u4f7f\u7528\u6ce8\u89e3\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e09\u3001\u81ea\u5b9a\u4e49\u6ce8\u89e3<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e00\uff09\u5b9a\u4e49\u81ea\u5b9a\u4e49\u6ce8\u89e3<\/h3>\n\n\n\n<p>\u81ea\u5b9a\u4e49\u6ce8\u89e3\u901a\u8fc7@interface\u5173\u952e\u5b57\u6765\u5b9a\u4e49\u3002\u4f8b\u5982\uff0c\u5b9a\u4e49\u4e00\u4e2a\u7b80\u5355\u7684\u81ea\u5b9a\u4e49\u6ce8\u89e3@MyAnnotation\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public @interface MyAnnotation {    \/\/ \u6ce8\u89e3\u53ef\u4ee5\u5305\u542b\u6210\u5458\u53d8\u91cf\uff0c\u8fd9\u91cc\u5b9a\u4e49\u4e00\u4e2a\u5b57\u7b26\u4e32\u7c7b\u578b\u7684\u6210\u5458\u53d8\u91cf    String value() default \"\";}<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0cMyAnnotation\u6ce8\u89e3\u6709\u4e00\u4e2a\u6210\u5458\u53d8\u91cfvalue\uff0c\u5e76\u4e14\u8bbe\u7f6e\u4e86\u9ed8\u8ba4\u503c\u4e3a\u7a7a\u5b57\u7b26\u4e32\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e8c\uff09\u6ce8\u89e3\u7684\u53c2\u6570<\/h3>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>\u8bed\u6cd5<\/strong>\uff1a\u53c2\u6570\u7c7b\u578b + \u53c2\u6570\u540d\uff08\uff09;<\/li>\n\n\n\n<li><strong>\u7c7b\u578b\u9650\u5236<\/strong>\uff1a\u6ce8\u89e3\u7684\u6210\u5458\u53d8\u91cf\u7c7b\u578b\u53ea\u80fd\u662f\u57fa\u672c\u7c7b\u578b\uff08\u5982int\u3001double\u7b49\uff09\u3001String\u3001Class\u3001enum\u3001Annotation\u4ee5\u53ca\u8fd9\u4e9b\u7c7b\u578b\u7684\u6570\u7ec4\u3002<\/li>\n\n\n\n<li><strong>\u9ed8\u8ba4\u503c<\/strong>\uff1a\u53ef\u4ee5\u4e3a\u6210\u5458\u53d8\u91cf\u8bbe\u7f6e\u9ed8\u8ba4\u503c\uff0c\u5982\u4e0a\u9762\u7684value\u53d8\u91cf\u8bbe\u7f6e\u4e86\u9ed8\u8ba4\u503c&#8221;&#8221;\u3002\u5982\u679c\u4e0d\u8bbe\u7f6e\u9ed8\u8ba4\u503c\uff0c\u5728\u4f7f\u7528\u6ce8\u89e3\u65f6\u5fc5\u987b\u663e\u5f0f\u8d4b\u503c\u3002<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e09\uff09\u4f7f\u7528\u81ea\u5b9a\u4e49\u6ce8\u89e3<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>@MyAnnotation(value = \"Hello, Annotation!\")public class MyClass {    \/\/ \u7c7b\u7684\u5185\u5bb9}<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0cMyClass\u7c7b\u4e0a\u4f7f\u7528\u4e86MyAnnotation\u6ce8\u89e3\uff0c\u5e76\u4e3avalue\u6210\u5458\u53d8\u91cf\u8d4b\u503c\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u56db\uff09\u6ce8\u89e3\u7684\u4fdd\u7559\u7b56\u7565<\/h3>\n\n\n\n<p>\u6ce8\u89e3\u7684\u4fdd\u7559\u7b56\u7565\u51b3\u5b9a\u4e86\u6ce8\u89e3\u5728\u4ec0\u4e48\u65f6\u5019\u53ef\u7528\uff0c\u901a\u8fc7Retention\u5143\u6ce8\u89e3\u6765\u8bbe\u7f6e\u3002RetentionPolicy\u6709\u4e09\u4e2a\u53d6\u503c\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>RetentionPolicy.SOURCE\uff1a\u6ce8\u89e3\u53ea\u5728\u6e90\u4ee3\u7801\u4e2d\u5b58\u5728\uff0c\u7f16\u8bd1\u65f6\u4f1a\u88ab\u4e22\u5f03\u3002<\/li>\n\n\n\n<li>RetentionPolicy.CLASS\uff1a\u6ce8\u89e3\u5728\u7f16\u8bd1\u540e\u7684\u5b57\u8282\u7801\u4e2d\u5b58\u5728\uff0c\u4f46\u8fd0\u884c\u65f6 JVM \u4e0d\u4f1a\u8bfb\u53d6\uff0c\u8fd9\u662f\u9ed8\u8ba4\u503c\u3002<\/li>\n\n\n\n<li>RetentionPolicy.RUNTIME\uff1a\u6ce8\u89e3\u5728\u8fd0\u884c\u65f6\u4ecd\u7136\u5b58\u5728\uff0cJVM \u53ef\u4ee5\u8bfb\u53d6\uff0c\u53ef\u4ee5\u901a\u8fc7\u53cd\u5c04\u83b7\u53d6\u6ce8\u89e3\u4fe1\u606f\u5e76\u8fdb\u884c\u5904\u7406\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\uff08\u4e94\uff09\u6ce8\u89e3\u7684\u76ee\u6807<\/h3>\n\n\n\n<p>\u6ce8\u89e3\u7684\u76ee\u6807\u6307\u5b9a\u4e86\u6ce8\u89e3\u53ef\u4ee5\u5e94\u7528\u5728\u54ea\u4e9b\u7a0b\u5e8f\u5143\u7d20\u4e0a\uff0c\u901a\u8fc7Target\u5143\u6ce8\u89e3\u6765\u8bbe\u7f6e\u3002ElementType\u6709\u591a\u4e2a\u53d6\u503c\uff0c\u5e38\u89c1\u7684\u6709\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>ElementType.TYPE\uff1a\u53ef\u4ee5\u5e94\u7528\u4e8e\u7c7b\u3001\u63a5\u53e3\u3001\u679a\u4e3e\u7b49\u7c7b\u578b\u3002<\/li>\n\n\n\n<li>ElementType.METHOD\uff1a\u53ef\u4ee5\u5e94\u7528\u4e8e\u65b9\u6cd5\u3002<\/li>\n\n\n\n<li>ElementType.FIELD\uff1a\u53ef\u4ee5\u5e94\u7528\u4e8e\u5b57\u6bb5\u3002<\/li>\n\n\n\n<li><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">\u56db\u3001\u8fd0\u884c\u65f6\u8bfb\u53d6\u6ce8\u89e3<\/h2>\n\n\n\n<p>\u5f53\u6ce8\u89e3\u7684\u4fdd\u7559\u7b56\u7565\u4e3aRetentionPolicy.RUNTIME\u65f6\uff0c\u53ef\u4ee5\u901a\u8fc7\u53cd\u5c04\u5728\u8fd0\u884c\u65f6\u8bfb\u53d6\u6ce8\u89e3\u4fe1\u606f\u3002\u4f8b\u5982\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>import java.lang.reflect.Method;\n\npublic class AnnotationReader {\n    public static void main(String&#91;] args) {\n        try {\n            Class&lt;?> clazz = MyClass.class;\n            Method method = clazz.getMethod(\"myMethod\");\n            MyAnnotation annotation = method.getAnnotation(MyAnnotation.class);\n            if (annotation!= null) {\n                System.out.println(\"\u6ce8\u89e3\u7684\u503c\uff1a\" + annotation.value());\n            }\n        } catch (NoSuchMethodException e) {\n            e.printStackTrace();\n        }\n    }\n}\n\n@MyAnnotation(value = \"\u8fd0\u884c\u65f6\u8bfb\u53d6\")\nclass MyClass {\n    public void myMethod() {\n        \/\/ \u65b9\u6cd5\u5185\u5bb9\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u901a\u8fc7\u53cd\u5c04\u83b7\u53d6MyClass\u7c7b\u7684myMethod\u65b9\u6cd5\u4e0a\u7684MyAnnotation\u6ce8\u89e3\uff0c\u5e76\u8f93\u51fa\u6ce8\u89e3\u7684\u503c\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00\u3001Java \u6ce8\u89e3\u57fa\u7840 \uff08\u4e00\uff09\u4ec0\u4e48\u662f\u6ce8\u89e3 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