{"id":612,"date":"2015-05-03T22:09:08","date_gmt":"2015-05-03T14:09:08","guid":{"rendered":"https:\/\/ai.zhousir.top\/?p=612"},"modified":"2026-08-18T12:09:32","modified_gmt":"2026-08-18T04:09:32","slug":"java%e8%a7%82%e5%af%9f%e8%80%85%e6%a8%a1%e5%bc%8fobservable%e4%b8%8eobserver-%e7%9a%84%e7%90%86%e8%a7%a3","status":"publish","type":"post","link":"https:\/\/ai.zhousir.top\/?p=612","title":{"rendered":"Java\u89c2\u5bdf\u8005\u6a21\u5f0fObservable\u4e0eObserver \u7684\u7406\u89e3"},"content":{"rendered":"
\n

JDK 1.2 \u4e4b\u540e\uff0cJava \u5728 java.util<\/code> \u91cc\u63d0\u4f9b\u4e86\u89c2\u5bdf\u8005\u6a21\u5f0f\u7684\u63a5\u53e3\u548c\u5b9e\u73b0\u7c7b\uff1a\u89c2\u5bdf\u8005\u5b9e\u73b0 Observer<\/code>\uff0c\u88ab\u89c2\u5bdf\u8005\u7ee7\u627f Observable<\/code>\u3002<\/p>\n

\u89c2\u5bdf\u8005\u5fc5\u987b\u5b9e\u73b0 void update(Observable o, Object arg)<\/code>\u3002\u8bfb\u8005\u53ef\u4ee5\u5f88\u8f7b\u6613\u5730\u7528\u8fd9\u4e00\u5bf9\u7c7b\u578b\u628a\u63a8\u9001\u5173\u7cfb\u642d\u8d77\u6765\u3002<\/p>\n

<\/p>\n

\u4e00\u3001Observer \u4e0e Observable<\/h2>\n

update<\/code> \u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f\u89e6\u53d1\u8fd9\u6b21\u901a\u77e5\u7684\u5bf9\u8c61\uff0c\u7b2c\u4e8c\u4e2a\u662f\u9644\u52a0\u53c2\u6570\u3002\u505a\u8fc7\u684c\u9762\u4e8b\u4ef6\u7684\u4f1a\u89c9\u5f97\u773c\u719f\uff1a\u524d\u8005\u50cf\u4e8b\u4ef6\u6e90\uff0c\u540e\u8005\u50cf\u6d88\u606f\u3002<\/p>\n\n\n\n\n\n\n
\u7c7b\u578b<\/th>\n\u89d2\u8272<\/th>\n\u5173\u952e\u65b9\u6cd5<\/th>\n<\/tr>\n<\/thead>\n
Observer<\/code><\/td>\n\u89c2\u5bdf\u8005<\/td>\nupdate(Observable o, Object arg)<\/code><\/td>\n<\/tr>\n
Observable<\/code><\/td>\n\u88ab\u89c2\u5bdf\u8005<\/td>\naddObserver<\/code> \/ setChanged<\/code> \/ notifyObservers<\/code> \/ deleteObserver<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u4e8c\u3001\u8bfb\u8005\u8ba2\u9605\u6742\u5fd7<\/h2>\n

\u51fa\u7248\u793e\u51fa\u6742\u5fd7\u65f6\u4e3b\u52a8\u544a\u77e5\u8bfb\u8005\u3002\u5148\u5199\u88ab\u89c2\u5bdf\u8005 Publisher<\/code>\uff08\u901a\u77e5\u524d\u8981 setChanged()<\/code>\uff09\uff1a<\/p>\n

package com.observer.observable;\n\nimport java.util.Observable;\n\npublic class Publisher extends Observable {\n\n    private String magazineName;\n\n    public String getMagazineName() {\n        return magazineName;\n    }\n\n    public void publish(String magazineName) {\n        this.magazineName = magazineName;\n        setChanged();\n        notifyObservers(this);\n    }\n}<\/code><\/pre>\n
\u8bfb\u8005\u5b9e\u73b0 Observer<\/code>\uff1a<\/p>\n
package com.observer.observer;\n\nimport java.util.Observable;\nimport java.util.Observer;\nimport com.observer.observable.Publisher;\n\npublic class Reader implements Observer {\n\n    @Override\n    public void update(Observable o, Object arg) {\n        Publisher p = (Publisher) o;\n        System.out.println(\"\u6211\u8981\u8ba2\u9605\" + p.getMagazineName());\n    }\n}<\/code><\/pre>\n
\u539f\u6587\u7b2c\u4e00\u6bb5\u6d4b\u8bd5\u53ea\u8c03\u7528\u4e86 publish<\/code>\uff0c\u6ca1\u6709 addObserver<\/code>\uff0c\u8bfb\u8005\u6536\u4e0d\u5230\u6d88\u606f\u3002\u5b8c\u6574\u6ce8\u518c\u5982\u4e0b\uff1a<\/p>\n
Publisher publisher = new Publisher();\nReader reader = new Reader();\npublisher.addObserver(reader);\npublisher.publish(\"\u6781\u5ba2\u4e4b\u5bb6\");<\/code><\/pre>\n
\u8fd9\u662f\u4e00\u79cd\u4e3b\u52a8\u63a8\u9001\uff1a\u51fa\u7248\u65f6\u901a\u77e5\u5df2\u6ce8\u518c\u7684\u8bfb\u8005\u3002<\/p>\n
\u4e09\u3001\u4e3a\u4ec0\u4e48 notifyObservers(this)\uff1f<\/h2>\n
\u540c\u4e00\u4e2a\u89c2\u5bdf\u8005\u53ef\u4ee5\u6302\u5230\u4e0d\u540c\u88ab\u89c2\u5bdf\u8005\u4e0a\uff0c\u4f20\u6765\u7684 Observable o<\/code> \u7528\u6765\u5206\u8fa8\u6d88\u606f\u662f\u8c01\u53d1\u7684\u3002\u518d\u5f15\u5165\u7535\u89c6\u53f0\uff1a<\/p>\n
package com.observer.observable;\n\nimport java.util.Observable;\n\npublic class TVStation extends Observable {\n\n    private String programmeName;\n\n    public void play(String programmeName) {\n        this.programmeName = programmeName;\n        setChanged();\n        notifyObservers(this);\n    }\n\n    public String getProgrammeName() {\n        return programmeName;\n    }\n}<\/code><\/pre>\n
package com.observer.observer;\n\nimport java.util.Observable;\nimport java.util.Observer;\nimport com.observer.observable.Publisher;\nimport com.observer.observable.TVStation;\n\npublic class Reader implements Observer {\n\n    @Override\n    public void update(Observable o, Object arg) {\n        if (o instanceof Publisher) {\n            Publisher p = (Publisher) o;\n            System.out.println(\"\u6211\u8981\u8ba2\u9605\" + p.getMagazineName());\n        }\n        if (o instanceof TVStation) {\n            TVStation t = (TVStation) o;\n            System.out.println(\"\u6211\u8981\u6536\u770b\" + t.getProgrammeName());\n        }\n    }\n}<\/code><\/pre>\n
package com.observer.test;\n\nimport org.junit.Test;\nimport com.observer.observable.Publisher;\nimport com.observer.observable.TVStation;\nimport com.observer.observer.Reader;\n\npublic class TestCase {\n\n    @Test\n    public void register() {\n        Reader reader = new Reader();\n\n        Publisher publisher = new Publisher();\n        publisher.addObserver(reader);\n\n        TVStation tvStation = new TVStation();\n        tvStation.addObserver(reader);\n\n        publisher.publish(\"\u6781\u5ba2\u4e4b\u5bb6\");\n        tvStation.play(\"\u8272\u6212\");\n    }\n}<\/code><\/pre>\n
\u56db\u3001\u6536\u5b8c\u6d88\u606f\u53ef\u4ee5\u53d6\u6d88\u8ba2\u9605<\/h2>\n
\u5728 update<\/code> \u91cc\u8c03\u7528 deleteObserver(this)<\/code> \u5373\u53ef\u64a4\u9500\u5bf9\u51fa\u7248\u793e\u7684\u89c2\u5bdf\uff1a<\/p>\n
@Override\npublic void update(Observable o, Object arg) {\n    if (o instanceof Publisher) {\n        Publisher p = (Publisher) o;\n        p.deleteObserver(this);\n        System.out.println(\"\u6211\u8981\u8ba2\u9605\" + p.getMagazineName());\n    }\n    if (o instanceof TVStation) {\n        TVStation t = (TVStation) o;\n        System.out.println(\"\u6211\u8981\u6536\u770b\" + t.getProgrammeName());\n    }\n}<\/code><\/pre>\n
\n
\u4e00\u53e5\u8bdd\u603b\u7ed3\uff1a\u5148 addObserver\uff0c\u518d setChanged + notifyObservers\uff1b\u4f20\u6765\u7684 Observable \u7528\u6765\u5206\u8fa8\u662f\u8c01\u5728\u63a8\uff0c\u4e0d\u770b\u4e86\u5c31 deleteObserver\u3002<\/strong><\/p>\n<\/blockquote>\n<\/section>\n","protected":false},"excerpt":{"rendered":"
JDK 1.2 \u4e4b\u540e\uff0cJava \u5728 java.util \u91cc\u63d0\u4f9b\u4e86\u89c2\u5bdf\u8005\u6a21\u5f0f\u7684\u63a5\u53e3\u548c\u5b9e\u73b0\u7c7b\uff1a\u89c2\u5bdf\u8005\u5b9e\u73b0 Obse […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[58],"tags":[43,179],"_links":{"self":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/612"}],"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=612"}],"version-history":[{"count":3,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/612\/revisions"}],"predecessor-version":[{"id":1461,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/612\/revisions\/1461"}],"wp:attachment":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=612"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=612"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=612"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}