{"id":612,"date":"2015-05-03T22:09:08","date_gmt":"2015-05-03T14:09:08","guid":{"rendered":"https:\/\/ai.zhousir.top\/?p=612"},"modified":"2016-03-09T14:48:25","modified_gmt":"2016-03-09T06:48:25","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":"<p>Part I<br \/>\nJDK1.2\u540e\uff0cJava\u63d0\u4f9b\u4e86\u5bf9\u89c2\u5bdf\u8005\u6a21\u5f0f\u7684\u652f\u6301\u63a5\u53e3\u548c\u5b9e\u73b0\u7c7b\u3002<br \/>\n\u5176\u4e2d\u63a5\u53e3 java.util.Observer \u7528\u6765\u6307\u5b9a\u89c2\u5bdf\u8005\uff0c\u89c2\u5bdf\u8005\u5fc5\u987b\u5b9e\u73b0 void update(Observable o, Object arg) \u65b9\u6cd5\u3002<br \/>\n\u800c java.util.Observable \u7528\u6765\u6307\u5b9a\u89c2\u5bdf\u7269\uff08\u88ab\u89c2\u5bdf\u8005\u3001\u53ef\u88ab\u89c2\u5bdf\u7684\uff09\uff0c\u5e76\u4e14\u63d0\u4f9b\u4e86\u4e00\u7cfb\u5217\u7684\u65b9\u6cd5\u3002\u8bfb\u8005\u53ef\u4ee5\u5f88\u8f7b\u6613\u7684\u4f7f\u7528\u8fd9\u4e2a\u63a5\u53e3\u548c\u5b9e\u73b0\u7c7b\u6765\u5b9e\u73b0\u89c2\u5bdf\u8005\u6a21\u5f0f\u3002<br \/>\n<!--more--><\/p>\n<p>Part II<br \/>\njava.util.Observer \u53ea\u6709\u4e00\u4e2a\u7b80\u5355\u7684\u65b9\u6cd5 void update(Observable o, Object arg)<br \/>\n\u5176\u4e2d\uff0c\u53c2\u6570 Observable o \u7528\u4e8e\u6307\u5b9a\u89e6\u53d1 update \u65b9\u6cd5\u7684\u5bf9\u8c61\uff0c Object arg \u7528\u4e8e\u6307\u5b9a\u89e6\u53d1 update \u65b9\u6cd5\u65f6\u5019\u7684\u9644\u52a0\u53c2\u6570\u3002<br \/>\n\u5982\u679c\u6709\u684c\u9762\u5e94\u7528\u5f00\u53d1\u7684\u8bfb\u8005\u5e94\u8be5\u5f88\u4e86\u89e3\uff0c\u8fd9\u8ddf\u4e8b\u4ef6\u5904\u7406\u673a\u5236\u662f\u5b8c\u5168\u4e00\u6837\u7684\uff0c\u5176\u4e2d Observable o \u53ef\u88ab\u770b\u4f5c\u4e8b\u4ef6\u6e90\u3002 Object arg \u53ef\u88ab\u770b\u4f5c\u6d88\u606f\u3002<\/p>\n<p>Part III<br \/>\n\u8bf4\u4e86\u90a3\u4e48\u591a\uff0c\u6211\u4eec\u8fd8\u662f\u52a8\u624b\u5199\u4e2a\u4f8b\u5b50\u5427\u3002\u8fd9\u91cc\u6211\u4eec\u4ee5\u8bfb\u8005\u8ba2\u9605\u6742\u5fd7\u4e3a\u4f8b\u5b50\u3002<\/p>\n<p>[java]package com.observer.observable;<\/p>\n<p>import java.util.Observable;<\/p>\n<p>public class Publisher extends Observable {<\/p>\n<p>    private String magazineName;<\/p>\n<p>    public String getMagazineName() {<br \/>\n        return magazineName;<br \/>\n    }<\/p>\n<p>    public void publish(String magazineName) {<br \/>\n        this.magazineName = magazineName;<br \/>\n        setChanged();<br \/>\n        notifyObservers(this);<br \/>\n    }<\/p>\n<p>}<\/p>\n<p>package com.observer.observer;<\/p>\n<p>import java.util.Observable;<br \/>\nimport java.util.Observer;<\/p>\n<p>import com.observer.observable.Publisher;<\/p>\n<p>public class Reader implements Observer {<\/p>\n<p>    @Override<br \/>\n    public void update(Observable o, Object arg) {<br \/>\n        Publisher p = (Publisher) o;<br \/>\n        System.out.println(&quot;\u6211\u8981\u8ba2\u9605&quot; + p.getMagazineName());<br \/>\n    }<\/p>\n<p>}<\/p>\n<p>package com.observer.test;<\/p>\n<p>import org.junit.Test;<\/p>\n<p>import com.observer.observable.Publisher;<\/p>\n<p>public class TestCase {<\/p>\n<p>    @Test<br \/>\n    public void register() {<\/p>\n<p>        Publisher publisher = new Publisher();<br \/>\n        publisher.publish(&quot;\u6781\u5ba2\u4e4b\u5bb6&quot;);<\/p>\n<p>    }<\/p>\n<p>}<br \/>\n[\/java]<\/p>\n<p>\u8fd9\u91cc\u5f88\u6e05\u695a\u7684\u770b\u5230\uff0c\u5f53\u51fa\u7248\u793e\u51fa\u7248\u6742\u5fd7\u7684\u65f6\u5019\uff0c\u4f1a\u4e3b\u52a8\u7684\u544a\u77e5\u8bfb\u8005\uff0c\u8bfb\u8005\u5c31\u4f1a\u8ba2\u9605\u6742\u5fd7\uff0c\u8fd9\u4e5f\u662f\u4e00\u79cd\u4e3b\u52a8\u63a8\u9001\u7684\u6a21\u5f0f\u3002<br \/>\nPart IV<\/p>\n<p>\u8fd9\u91cc\u5927\u5bb6\u4f1a\u53d1\u73b0\uff0c\u8c03\u7528 notifyObservers() \u7684\u65f6\u5019\uff0c\u4e3a\u4ec0\u4e48\u4f20\u8fdb\u5f53\u524d\u5bf9\u8c61 this \u5462\uff1f\u800c\u8fd9\u4e2a this\uff0c \u6211\u4eec\u5728\u8bfb\u8005\u90a3\u4e5f\u6ca1\u7528\u5230\u554a\u3002\u8fd9\u4e2a\u95ee\u9898\u66fe\u7ecf\u4e5f\u8ba9\u6211\u89c9\u5f97\u5f88\u82e6\u607c\uff0c\u4e4b\u524d\u6211\u4e5f\u4e0d\u6e05\u695a\u4e3a\u4ec0\u4e48\u89c2\u5bdf\u8005\u8981\u62ff\u5230\u88ab\u89c2\u5bdf\u5bf9\u8c61\u7684\u5f15\u7528\uff0c\u4f46\u662f\uff0c\u6211\u4eec\u770b\u770b\u4e0b\u9762\u8fd9\u4e2a\u4f8b\u5b50\u3002<br \/>\n\u9996\u5148\u6211\u4eec\u5f15\u7528\u4e00\u4e2a\u65b0\u7684\u7c7b\uff1a<\/p>\n<p>[java]package com.observer.observable;<\/p>\n<p>import java.util.Observable;<\/p>\n<p>public class TVStation extends Observable {<\/p>\n<p>    private String programmeName;<\/p>\n<p>    public void play(String programmeName) {<br \/>\n        this.programmeName = programmeName;<br \/>\n        setChanged();<br \/>\n        notifyObservers(this);<br \/>\n    }<\/p>\n<p>    public String getProgrammeName() {<br \/>\n        return programmeName;<br \/>\n    }<\/p>\n<p>}<br \/>\n[\/java]<\/p>\n<p>\u7136\u540e\u4fee\u6539Reader\u548cTestCase\uff1a<\/p>\n<p>[java]package com.observer.observer;<\/p>\n<p>import java.util.Observable;<br \/>\nimport java.util.Observer;<\/p>\n<p>import com.observer.observable.Publisher;<br \/>\nimport com.observer.observable.TVStation;<\/p>\n<p>public class Reader implements Observer {<\/p>\n<p>    @Override<br \/>\n    public void update(Observable o, Object arg) {<br \/>\n        if (o instanceof Publisher) {<br \/>\n            Publisher p = (Publisher) o;<br \/>\n            System.out.println(&quot;\u6211\u8981\u8ba2\u9605&quot; + p.getMagazineName());<br \/>\n        }<br \/>\n        if (o instanceof TVStation) {<br \/>\n            TVStation t = (TVStation) o;<br \/>\n            System.out.println(&quot;\u6211\u8981\u6536\u770b&quot; + t.getProgrammeName());<br \/>\n        }<br \/>\n    }<\/p>\n<p>}<\/p>\n<p>package com.observer.test;<\/p>\n<p>import org.junit.Test;<\/p>\n<p>import com.observer.observable.Publisher;<br \/>\nimport com.observer.observable.TVStation;<br \/>\nimport com.observer.observer.Reader;<\/p>\n<p>public class TestCase {<\/p>\n<p>    @Test<br \/>\n    public void register() {<\/p>\n<p>        Reader reader = new Reader();<\/p>\n<p>        Publisher publisher = new Publisher();<br \/>\n        publisher.addObserver(reader);<\/p>\n<p>        TVStation tvStation = new TVStation();<br \/>\n        tvStation.addObserver(reader);<\/p>\n<p>        publisher.publish(&quot;\u6781\u5ba2\u4e4b\u5bb6&quot;);<br \/>\n        tvStation.play(&quot;\u8272\u6212&quot;);<\/p>\n<p>    }<\/p>\n<p>}<br \/>\n[\/java]<\/p>\n<p>\u6700\u540e\u6211\u4eec\u53ef\u4ee5\u770b\u5230\uff0c<strong>\u540c\u4e00\u4e2a\u89c2\u5bdf\u8005\u5176\u5b9e\u662f\u53ef\u4ee5\u6ce8\u518c\u5230\u4e0d\u540c\u7684\u88ab\u89c2\u5bdf\u8005\u4e0a\u9762\u7684\uff0c\u800c\u4f20\u8fc7\u6765\u7684 Oberverable o \u5176\u5b9e\u53ef\u4ee5\u7528\u6765\u68c0\u9a8c\u5230\u5e95\u662f\u8c01\u53d1\u8fc7\u6765\u7684\u6d88\u606f\u3002<\/strong><br \/>\n\u9664\u6b64\u4ee5\u5916\uff0c\u6211\u4eec\u8fd8\u53ef\u4ee5\u5728\u63a5\u53d7\u5230\u6d88\u606f\u4e4b\u540e\uff0c\u8fdb\u884c\u64a4\u9500\u89c2\u5bdf\u7684\u5de5\u4f5c\u3002<\/p>\n<p>[java]package com.observer.observer;<\/p>\n<p>import java.util.Observable;<br \/>\nimport java.util.Observer;<\/p>\n<p>import com.observer.observable.Publisher;<br \/>\nimport com.observer.observable.TVStation;<\/p>\n<p>public class Reader implements Observer {<\/p>\n<p>    @Override<br \/>\n    public void update(Observable o, Object arg) {<br \/>\n        if (o instanceof Publisher) {<br \/>\n            Publisher p = (Publisher) o;<br \/>\n            p.deleteObserver(this);<br \/>\n            System.out.println(&quot;\u6211\u8981\u8ba2\u9605&quot; + p.getMagazineName());<br \/>\n        }<br \/>\n        if (o instanceof TVStation) {<br \/>\n            TVStation t = (TVStation) o;<br \/>\n            System.out.println(&quot;\u6211\u8981\u6536\u770b&quot; + t.getProgrammeName());<br \/>\n        }<br \/>\n    }<\/p>\n<p>}[\/java]<\/p>\n<p>\u901a\u8fc7 deleteObserver() \u65b9\u6cd5\u5c31\u53ef\u4ee5\u64a4\u9500\u89c2\u5bdf\u51fa\u7248\u793e\u5bf9\u8c61\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Part I JDK1.2\u540e\uff0cJava\u63d0\u4f9b\u4e86\u5bf9\u89c2\u5bdf\u8005\u6a21\u5f0f\u7684\u652f\u6301\u63a5\u53e3\u548c\u5b9e\u73b0\u7c7b\u3002 \u5176\u4e2d\u63a5\u53e3 java.util.O [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[58],"tags":[],"_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":4,"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}]}}