{"id":87,"date":"2015-03-30T11:45:51","date_gmt":"2015-03-30T03:45:51","guid":{"rendered":"https:\/\/ai.zhousir.top\/?p=87"},"modified":"2026-08-18T12:09:25","modified_gmt":"2026-08-18T04:09:25","slug":"java-instanceof-%e8%bf%90%e7%ae%97%e7%ac%a6","status":"publish","type":"post","link":"https:\/\/ai.zhousir.top\/?p=87","title":{"rendered":"Java instanceof \u8fd0\u7b97\u7b26"},"content":{"rendered":"
\n

\u591a\u6001\u5e26\u6765\u4e00\u4e2a\u5b9e\u9645\u95ee\u9898\uff1a\u53d8\u91cf\u58f0\u660e\u7c7b\u578b\u662f\u7236\u7c7b\uff0c\u600e\u4e48\u5224\u65ad\u5b83\u5b9e\u9645\u5f15\u7528<\/strong>\u7684\u5bf9\u8c61\u662f\u54ea\u4e00\u79cd\uff1fJava \u7528 instanceof<\/code> \u8fd0\u7b97\u7b26\u3002<\/p>\n

obj instanceof Type<\/code> \u770b\u7684\u662f\u5bf9\u8c61\u7684\u771f\u5b9e\u7c7b\u578b\uff0c\u4e0d\u662f\u53d8\u91cf\u7684\u58f0\u660e\u7c7b\u578b\u3002\u771f\u5b9e\u5bf9\u8c61\u662f Type \u672c\u8eab\uff0c\u6216 Type \u7684\u5b50\u7c7b\uff0c\u7ed3\u679c\u4e3a true\u3002<\/p>\n

\u4e00\u3001\u7ee7\u627f\u94fe<\/h2>\n
class People {\n}\nclass Teacher extends People {\n}\nclass President extends Teacher {\n}<\/code><\/pre>\n
\u94fe\u662f Object \u2192 People \u2192 Teacher \u2192 President\u3002\u8d8a\u5f80\u4e0b\u8d8a\u5177\u4f53\u3002<\/p>\n
\u4e8c\u3001\u540c\u4e00\u53d8\u91cf\uff0c\u4e24\u79cd\u5b9e\u9645\u5bf9\u8c61<\/h2>\n
public class Demo {\n    public static void main(String[] args) {\n        People obj = new People();\n        if (obj instanceof Object) {\n            System.out.println(\"\u6211\u662f\u4e00\u4e2a\u5bf9\u8c61\");\n        }\n        if (obj instanceof People) {\n            System.out.println(\"\u6211\u662f\u4eba\u7c7b\");\n        }\n        if (obj instanceof Teacher) {\n            System.out.println(\"\u6211\u662f\u4e00\u540d\u6559\u5e08\");\n        }\n        if (obj instanceof President) {\n            System.out.println(\"\u6211\u662f\u6821\u957f\");\n        }\n        System.out.println(\"-----------\");\n\n        obj = new Teacher();\n        if (obj instanceof Object) {\n            System.out.println(\"\u6211\u662f\u4e00\u4e2a\u5bf9\u8c61\");\n        }\n        if (obj instanceof People) {\n            System.out.println(\"\u6211\u662f\u4eba\u7c7b\");\n        }\n        if (obj instanceof Teacher) {\n            System.out.println(\"\u6211\u662f\u4e00\u540d\u6559\u5e08\");\n        }\n        if (obj instanceof President) {\n            System.out.println(\"\u6211\u662f\u6821\u957f\");\n        }\n    }\n}\n\/\/ \u8fd0\u884c\u7ed3\u679c\uff1a\n\/\/ \u6211\u662f\u4e00\u4e2a\u5bf9\u8c61\n\/\/ \u6211\u662f\u4eba\u7c7b\n\/\/ -----------\n\/\/ \u6211\u662f\u4e00\u4e2a\u5bf9\u8c61\n\/\/ \u6211\u662f\u4eba\u7c7b\n\/\/ \u6211\u662f\u4e00\u540d\u6559\u5e08<\/code><\/pre>\n\n\n\n\n\n\n
\u5b9e\u9645\u5bf9\u8c61<\/th>\ninstanceof Object \/ People<\/th>\ninstanceof Teacher \/ President<\/th>\n<\/tr>\n<\/thead>\n
new People()<\/td>\ntrue \/ true<\/td>\nfalse \/ false<\/td>\n<\/tr>\n
new Teacher()<\/td>\ntrue \/ true<\/td>\ntrue \/ false<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Teacher \u662f People \u7684\u5b50\u7c7b\uff0c\u6240\u4ee5 new Teacher() instanceof People<\/code> \u4e3a true\uff1bPeople \u4e0d\u662f Teacher\uff0c\u6240\u4ee5\u7b2c\u4e00\u6bb5\u4e0d\u4f1a\u6253\u5370\u300c\u6211\u662f\u4e00\u540d\u6559\u5e08\u300d\u3002\u5411\u4e0b\u95ee\u66f4\u5177\u4f53\u7684\u7c7b\u578b\uff0c\u53ea\u6709\u5b9e\u9645\u5bf9\u8c61\u591f\u300c\u5177\u4f53\u300d\u624d\u4e3a true\u3002<\/p>\n
\n
\u4e00\u53e5\u8bdd\u603b\u7ed3\uff1ainstanceof \u95ee\u7684\u662f\u5806\u4e0a\u90a3\u4e2a\u5bf9\u8c61\u662f\u4e0d\u662f\u67d0\u7c7b\u578b\u6216\u5176\u5b50\u7c7b\uff0c\u4e0d\u95ee\u53d8\u91cf\u5199\u6210\u4e86\u4ec0\u4e48\u7c7b\u578b\u3002<\/strong><\/p>\n<\/blockquote>\n<\/section>\n","protected":false},"excerpt":{"rendered":"
\u591a\u6001\u5e26\u6765\u4e00\u4e2a\u5b9e\u9645\u95ee\u9898\uff1a\u53d8\u91cf\u58f0\u660e\u7c7b\u578b\u662f\u7236\u7c7b\uff0c\u600e\u4e48\u5224\u65ad\u5b83\u5b9e\u9645\u5f15\u7528\u7684\u5bf9\u8c61\u662f\u54ea\u4e00\u79cd\uff1fJava \u7528 instanceof […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[16],"tags":[43,32],"_links":{"self":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/87"}],"collection":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=87"}],"version-history":[{"count":3,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/87\/revisions"}],"predecessor-version":[{"id":2081,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/87\/revisions\/2081"}],"wp:attachment":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=87"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=87"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=87"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}