{"id":2238,"date":"2025-03-02T11:14:06","date_gmt":"2025-03-02T03:14:06","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2238"},"modified":"2025-03-02T11:14:06","modified_gmt":"2025-03-02T03:14:06","slug":"java-%e6%9e%9a%e4%b8%be-enum","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/02\/java-%e6%9e%9a%e4%b8%be-enum\/","title":{"rendered":"Java \u679a\u4e3e (Enum)"},"content":{"rendered":"\n

Java \u679a\u4e3e\uff08enum<\/code>\uff09\u662f\u4e00\u79cd\u7279\u6b8a\u7684\u7c7b\uff0c\u7528\u4e8e\u8868\u793a\u4e00\u7ec4\u56fa\u5b9a\u7684\u5e38\u91cf\u3002enum<\/code> \u5728 Java \u4e2d\u662f\u4e00\u4e2a\u5f15\u7528\u6570\u636e\u7c7b\u578b\uff0c\u53ef\u4ee5\u7528\u4e8e\u8868\u793a\u4e00\u7ec4\u9884\u5b9a\u4e49\u7684\u5e38\u91cf\uff0c\u4f8b\u5982\u4e00\u5468\u7684\u4e03\u5929\u3001\u5b63\u8282\u3001\u72b6\u6001\u7801\u7b49\u3002<\/p>\n\n\n\n

Java \u679a\u4e3e\u662f java.lang.Enum<\/code> \u7c7b\u7684\u4e00\u4e2a\u5b50\u7c7b\uff0c\u5177\u5907\u4e86\u5f88\u591a\u7279\u6b8a\u529f\u80fd\uff0c\u5141\u8bb8\u4f60\u5b9a\u4e49\u6709\u9650\u4e2a\u6570\u7684\u5e38\u91cf\uff0c\u5e76\u63d0\u4f9b\u4e86\u5f3a\u5927\u7684\u529f\u80fd\uff0c\u5982 switch<\/code> \u5224\u65ad\u3001\u904d\u5386\u3001\u4e0e\u5176\u4ed6\u5bf9\u8c61\u6bd4\u8f83\u7b49\u3002<\/p>\n\n\n\n

1. \u679a\u4e3e\u7684\u57fa\u672c\u8bed\u6cd5<\/strong><\/h3>\n\n\n\n

\u679a\u4e3e\u7684\u58f0\u660e\u4f7f\u7528 enum<\/code> \u5173\u952e\u5b57\uff0c\u679a\u4e3e\u7684\u6bcf\u4e2a\u5e38\u91cf\u901a\u5e38\u4ee5\u5927\u5199\u5b57\u6bcd\u8868\u793a\u3002<\/p>\n\n\n\n

enum Day {\n    MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY\n}<\/code><\/pre>\n\n\n\n
2. \u4f7f\u7528\u679a\u4e3e<\/strong><\/h3>\n\n\n\n
\u4e00\u65e6\u5b9a\u4e49\u4e86\u679a\u4e3e\u7c7b\u578b\uff0c\u5c31\u53ef\u4ee5\u901a\u8fc7\u679a\u4e3e\u5e38\u91cf\u6765\u5f15\u7528\u5b83\u4eec\u3002<\/p>\n\n\n\n
public class EnumExample {\n    public static void main(String[] args) {\n        Day today = Day.MONDAY;\n\n        switch (today) {\n            case MONDAY:\n                System.out.println(\"Start of the workweek\");\n                break;\n            case FRIDAY:\n                System.out.println(\"Almost the weekend\");\n                break;\n            case SUNDAY:\n                System.out.println(\"Weekend is over\");\n                break;\n            default:\n                System.out.println(\"Midweek days\");\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
Start of the workweek<\/code><\/pre>\n\n\n\n
3. \u679a\u4e3e\u7684\u5b57\u6bb5\u3001\u6784\u9020\u65b9\u6cd5\u548c\u65b9\u6cd5<\/strong><\/h3>\n\n\n\n
\u679a\u4e3e\u4e0d\u4ec5\u4ec5\u662f\u4e00\u4e9b\u5e38\u91cf\uff0c\u5b83\u53ef\u4ee5\u6709\u5b57\u6bb5\u3001\u6784\u9020\u65b9\u6cd5\u548c\u65b9\u6cd5\u3002\u6bcf\u4e2a\u679a\u4e3e\u5e38\u91cf\u90fd\u53ef\u4ee5\u4e0e\u6570\u636e\u548c\u884c\u4e3a\u5173\u8054\u3002<\/p>\n\n\n\n
3.1 \u679a\u4e3e\u7684\u5b57\u6bb5\u548c\u6784\u9020\u65b9\u6cd5<\/strong><\/h4>\n\n\n\n
\u53ef\u4ee5\u4e3a\u679a\u4e3e\u5b9a\u4e49\u5b57\u6bb5\uff08\u4f8b\u5982\uff0c\u5b58\u50a8\u679a\u4e3e\u5e38\u91cf\u76f8\u5173\u7684\u503c\uff09\u548c\u6784\u9020\u65b9\u6cd5\u3002\u6784\u9020\u65b9\u6cd5\u5728\u679a\u4e3e\u5e38\u91cf\u521b\u5efa\u65f6\u4f1a\u8c03\u7528\u3002<\/p>\n\n\n\n
enum Day {\n    MONDAY(\"Work day\"), TUESDAY(\"Work day\"), WEDNESDAY(\"Work day\"),\n    THURSDAY(\"Work day\"), FRIDAY(\"Work day\"), SATURDAY(\"Weekend\"),\n    SUNDAY(\"Weekend\");\n\n    private String type;\n\n    \/\/ \u6784\u9020\u65b9\u6cd5\n    Day(String type) {\n        this.type = type;\n    }\n\n    \/\/ \u65b9\u6cd5\n    public String getType() {\n        return this.type;\n    }\n}\n\npublic class EnumExample {\n    public static void main(String[] args) {\n        Day today = Day.MONDAY;\n        System.out.println(today + \": \" + today.getType()); \/\/ \u8f93\u51fa \"MONDAY: Work day\"\n    }\n}<\/code><\/pre>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
MONDAY: Work day<\/code><\/pre>\n\n\n\n
3.2 \u679a\u4e3e\u7684\u65b9\u6cd5<\/strong><\/h4>\n\n\n\n
\u4f60\u53ef\u4ee5\u5728\u679a\u4e3e\u4e2d\u5b9a\u4e49\u65b9\u6cd5\u6765\u5904\u7406\u4e0e\u5e38\u91cf\u76f8\u5173\u7684\u903b\u8f91\u3002\u6bd4\u5982\uff1a<\/p>\n\n\n\n
enum Day {\n    MONDAY(\"Work day\", 1), TUESDAY(\"Work day\", 2), WEDNESDAY(\"Work day\", 3),\n    THURSDAY(\"Work day\", 4), FRIDAY(\"Work day\", 5), SATURDAY(\"Weekend\", 6),\n    SUNDAY(\"Weekend\", 7);\n\n    private String type;\n    private int dayNumber;\n\n    Day(String type, int dayNumber) {\n        this.type = type;\n        this.dayNumber = dayNumber;\n    }\n\n    public String getType() {\n        return this.type;\n    }\n\n    public int getDayNumber() {\n        return this.dayNumber;\n    }\n}\n\npublic class EnumExample {\n    public static void main(String[] args) {\n        for (Day day : Day.values()) {\n            System.out.println(day + \": \" + day.getType() + \", Day number: \" + day.getDayNumber());\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
MONDAY: Work day, Day number: 1\nTUESDAY: Work day, Day number: 2\nWEDNESDAY: Work day, Day number: 3\nTHURSDAY: Work day, Day number: 4\nFRIDAY: Work day, Day number: 5\nSATURDAY: Weekend, Day number: 6\nSUNDAY: Weekend, Day number: 7<\/code><\/pre>\n\n\n\n
4. \u679a\u4e3e\u7684\u5185\u7f6e\u65b9\u6cd5<\/strong><\/h3>\n\n\n\n
\u679a\u4e3e\u7c7b\u9ed8\u8ba4\u7ee7\u627f java.lang.Enum<\/code> \u7c7b\uff0c\u56e0\u6b64\u5b83\u6709\u4e00\u4e9b\u5185\u7f6e\u7684\u65b9\u6cd5\u3002\u5e38\u7528\u7684\u5185\u7f6e\u65b9\u6cd5\u5305\u62ec\uff1a<\/p>\n\n\n\n
4.1 values()<\/code><\/strong><\/h4>\n\n\n\n
\u8fd4\u56de\u4e00\u4e2a\u5305\u542b\u6240\u6709\u679a\u4e3e\u5e38\u91cf\u7684\u6570\u7ec4\uff0c\u6309\u5b83\u4eec\u5728\u679a\u4e3e\u5b9a\u4e49\u4e2d\u7684\u58f0\u660e\u987a\u5e8f\u8fd4\u56de\u3002<\/p>\n\n\n\n
public class EnumExample {\n    public static void main(String[] args) {\n        \/\/ \u83b7\u53d6\u6240\u6709\u679a\u4e3e\u5e38\u91cf\n        Day[] days = Day.values();\n        for (Day day : days) {\n            System.out.println(day);\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
MONDAY\nTUESDAY\nWEDNESDAY\nTHURSDAY\nFRIDAY\nSATURDAY\nSUNDAY<\/code><\/pre>\n\n\n\n
4.2 valueOf(String name)<\/code><\/strong><\/h4>\n\n\n\n
\u5c06\u4e00\u4e2a\u5b57\u7b26\u4e32\u4e0e\u679a\u4e3e\u5e38\u91cf\u7684\u540d\u79f0\u8fdb\u884c\u5339\u914d\uff0c\u5e76\u8fd4\u56de\u5bf9\u5e94\u7684\u679a\u4e3e\u5e38\u91cf\u3002<\/p>\n\n\n\n
public class EnumExample {\n    public static void main(String[] args) {\n        Day day = Day.valueOf(\"MONDAY\");\n        System.out.println(\"The selected day is: \" + day);\n    }\n}<\/code><\/pre>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
The selected day is: MONDAY<\/code><\/pre>\n\n\n\n
\u5982\u679c\u4f20\u5165\u7684\u5b57\u7b26\u4e32\u4e0d\u5728\u679a\u4e3e\u5e38\u91cf\u4e2d\uff0c\u4f1a\u629b\u51fa IllegalArgumentException<\/code>\u3002<\/p>\n\n\n\n
4.3 ordinal()<\/code><\/strong><\/h4>\n\n\n\n
\u8fd4\u56de\u679a\u4e3e\u5e38\u91cf\u7684\u5e8f\u53f7\uff08\u4ece 0 \u5f00\u59cb\uff09\u3002<\/p>\n\n\n\n
public class EnumExample {\n    public static void main(String[] args) {\n        Day day = Day.MONDAY;\n        System.out.println(day + \" ordinal is: \" + day.ordinal());\n    }\n}<\/code><\/pre>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
MONDAY ordinal is: 0<\/code><\/pre>\n\n\n\n
4.4 compareTo()<\/code><\/strong><\/h4>\n\n\n\n
\u4e0e ordinal()<\/code> \u7c7b\u4f3c\uff0ccompareTo()<\/code> \u65b9\u6cd5\u6bd4\u8f83\u5f53\u524d\u679a\u4e3e\u5e38\u91cf\u548c\u6307\u5b9a\u679a\u4e3e\u5e38\u91cf\u7684\u4f4d\u7f6e\uff0c\u8fd4\u56de\u4e00\u4e2a\u6574\u6570\u503c\uff0c\u8868\u793a\u5b83\u4eec\u5728\u679a\u4e3e\u4e2d\u4f4d\u7f6e\u7684\u76f8\u5bf9\u987a\u5e8f\u3002<\/p>\n\n\n\n
public class EnumExample {\n    public static void main(String[] args) {\n        Day day1 = Day.MONDAY;\n        Day day2 = Day.FRIDAY;\n        System.out.println(day1.compareTo(day2));  \/\/ \u8f93\u51fa -4\uff0c\u56e0\u4e3a MONDAY \u5728 FRIDAY \u524d\n    }\n}<\/code><\/pre>\n\n\n\n
5. \u679a\u4e3e\u7684\u5b9e\u9645\u5e94\u7528<\/strong><\/h3>\n\n\n\n
5.1 \u679a\u4e3e\u4e0e switch<\/code> \u8bed\u53e5<\/strong><\/h4>\n\n\n\n
\u7531\u4e8e\u679a\u4e3e\u503c\u662f\u5e38\u91cf\uff0c\u56e0\u6b64\u53ef\u4ee5\u76f4\u63a5\u7528\u4e8e switch<\/code> \u8bed\u53e5\u4e2d\uff0c\u8fd9\u6837\u53ef\u4ee5\u8ba9\u4ee3\u7801\u66f4\u52a0\u6e05\u6670\u548c\u5b89\u5168\u3002<\/p>\n\n\n\n
public class EnumExample {\n    public static void main(String[] args) {\n        Day today = Day.WEDNESDAY;\n\n        switch (today) {\n            case MONDAY:\n                System.out.println(\"Start of the work week\");\n                break;\n            case FRIDAY:\n                System.out.println(\"Almost the weekend\");\n                break;\n            case SATURDAY:\n            case SUNDAY:\n                System.out.println(\"Weekend!\");\n                break;\n            default:\n                System.out.println(\"Midweek day\");\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
5.2 \u679a\u4e3e\u7528\u4e8e\u72b6\u6001\u673a\u6a21\u5f0f<\/strong><\/h4>\n\n\n\n
\u53ef\u4ee5\u4f7f\u7528\u679a\u4e3e\u6765\u5b9a\u4e49\u72b6\u6001\u673a\u7684\u4e0d\u540c\u72b6\u6001\uff0c\u5e76\u7ed3\u5408\u65b9\u6cd5\u6765\u6539\u53d8\u72b6\u6001\u7684\u884c\u4e3a\u3002<\/p>\n\n\n\n
enum OrderStatus {\n    NEW {\n        @Override\n        public void handle() {\n            System.out.println(\"Order is new. Handle it.\");\n        }\n    },\n    SHIPPED {\n        @Override\n        public void handle() {\n            System.out.println(\"Order is shipped. Handle shipping.\");\n        }\n    },\n    DELIVERED {\n        @Override\n        public void handle() {\n            System.out.println(\"Order is delivered. Finalize the order.\");\n        }\n    };\n\n    public abstract void handle(); \/\/ \u62bd\u8c61\u65b9\u6cd5\n}\n\npublic class EnumExample {\n    public static void main(String[] args) {\n        OrderStatus status = OrderStatus.NEW;\n        status.handle(); \/\/ \u8f93\u51fa \"Order is new. Handle it.\"\n    }\n}<\/code><\/pre>\n\n\n\n
6. \u603b\u7ed3<\/strong><\/h3>\n\n\n\n
    \n
  • \u5b9a\u4e49\u679a\u4e3e<\/strong>\uff1a\u901a\u8fc7 enum<\/code> \u5173\u952e\u5b57\uff0c\u5b9a\u4e49\u4e00\u7ec4\u6709\u9650\u7684\u5e38\u91cf\u3002<\/li>\n\n\n\n
  • \u679a\u4e3e\u5e38\u91cf<\/strong>\uff1a\u53ef\u4ee5\u5305\u542b\u5b57\u6bb5\u3001\u6784\u9020\u65b9\u6cd5\u3001\u65b9\u6cd5\u548c\u679a\u4e3e\u5e38\u91cf\u3002<\/li>\n\n\n\n
  • \u5185\u7f6e\u65b9\u6cd5<\/strong>\uff1avalues()<\/code>, valueOf()<\/code>, ordinal()<\/code>, compareTo()<\/code> \u7b49\u65b9\u6cd5\u4f7f\u5f97\u679a\u4e3e\u66f4\u5177\u529f\u80fd\u3002<\/li>\n\n\n\n
  • \u5e94\u7528\u573a\u666f<\/strong>\uff1a\u5e38\u7528\u4e8e\u8868\u793a\u6709\u9650\u7684\u72b6\u6001\u96c6\u5408\u3001\u7b56\u7565\u6a21\u5f0f\u3001\u4e8b\u4ef6\u5904\u7406\u3001\u72b6\u6001\u673a\u7b49\u3002<\/li>\n<\/ul>\n\n\n\n
    \u901a\u8fc7\u679a\u4e3e\uff0c\u53ef\u4ee5\u4f7f\u4ee3\u7801\u66f4\u52a0\u6e05\u6670\u3001\u7c7b\u578b\u5b89\u5168\uff0c\u5e76\u6709\u6548\u907f\u514d\u786c\u7f16\u7801\u3002\u4f60\u53ef\u4ee5\u5c06\u679a\u4e3e\u5e94\u7528\u5230\u5f88\u591a\u573a\u666f\u4e2d\uff0c\u5c24\u5176\u662f\u90a3\u4e9b\u9700\u8981\u5b9a\u4e49\u56fa\u5b9a\u5e38\u91cf\u7684\u5730\u65b9\u3002\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
    Java \u679a\u4e3e\uff08enum\uff09\u662f\u4e00\u79cd\u7279\u6b8a\u7684\u7c7b\uff0c\u7528\u4e8e\u8868\u793a\u4e00\u7ec4\u56fa\u5b9a\u7684\u5e38\u91cf\u3002enum \u5728 Java \u4e2d\u662f\u4e00\u4e2a\u5f15\u7528\u6570\u636e\u7c7b\u578b […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[68],"tags":[],"class_list":["post-2238","post","type-post","status-publish","format-standard","hentry","category-java"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2238","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=2238"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2238\/revisions"}],"predecessor-version":[{"id":2239,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2238\/revisions\/2239"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2238"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2238"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2238"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}