{"id":2746,"date":"2018-05-01T11:16:11","date_gmt":"2018-05-01T03:16:11","guid":{"rendered":"http:\/\/www.xttblog.com\/?p=2746"},"modified":"2018-05-01T11:16:11","modified_gmt":"2018-05-01T03:16:11","slug":"%e8%af%a6%e8%a7%a3-java-%e4%b8%ad%e7%9a%84-iterable%e3%80%81itetator%e3%80%81enumeration","status":"publish","type":"post","link":"https:\/\/www.xttblog.com\/?p=2746","title":{"rendered":"\u8be6\u89e3 Java \u4e2d\u7684 Iterable\u3001Itetator\u3001Enumeration"},"content":{"rendered":"

\n\tJava \u4e2d\u5bf9\u4e00\u4e9b\u96c6\u5408\u5faa\u73af\u904d\u5386\u505a\u4e86\u4e00\u4e9b\u7279\u6b8a\u7684\u5c01\u88c5\u3002\u4e00\u4e9b\u662f\u65b9\u4fbf\u6211\u4eec\u7684\u64cd\u4f5c\uff0c\u4e00\u4e9b\u662f\u5b58\u5728\u5b58\u50a8\u6027\u80fd\u7b49\u65b9\u9762\u8bbe\u8ba1\u7684\u3002\u5173\u4e8e Iterable\u3001Itetator\u3001Enumeration\uff0c\u6211\u4eec\u4e00\u8d77\u6765\u5b66\u4e60\u5b83\u4eec\u3002\n<\/p>\n

\n\tIterable
\n<\/h2>\n

\n\tIterable\u63a5\u53e3\u5b9e\u73b0\u540e\u7684\u529f\u80fd\u662f“\u8fd4\u56de”\u4e00\u4e2a\u8fed\u4ee3\u5668,\u6211\u4eec\u5e38\u7528\u7684\u5b9e\u73b0\u4e86\u8be5\u63a5\u53e3\u7684\u5b50\u63a5\u53e3\u6709: Collection, Deque, List, Queue, Set \u7b49.\u8be5\u63a5\u53e3\u7684iterator()\u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2a\u6807\u51c6\u7684Iterator\u5b9e\u73b0\u3002\u5b9e\u73b0\u8fd9\u4e2a\u63a5\u53e3\u5141\u8bb8\u5bf9\u8c61\u6210\u4e3a For each \u8bed\u53e5\u7684\u76ee\u6807\u3002\u5c31\u53ef\u4ee5\u901a\u8fc7For each\u8bed\u6cd5\u904d\u5386\u5e95\u5c42\u5e8f\u5217\u3002\n<\/p>\n

\n\t\u91c7\u7528ArrayList\u5bf9\u968f\u673a\u8bbf\u95ee\u6bd4\u8f83\u5feb\uff0c\u800cfor\u5faa\u73af\u4e2d\u7684get()\u65b9\u6cd5\uff0c\u91c7\u7528\u7684\u5373\u662f\u968f\u673a\u8bbf\u95ee\u7684\u65b9\u6cd5\uff0c\u56e0\u6b64\u5728ArrayList\u91cc\uff0cfor\u5faa\u73af\u8f83\u5feb\u3002\n<\/p>\n

\n\t\u91c7\u7528LinkedList\u5219\u662f\u987a\u5e8f\u8bbf\u95ee\u6bd4\u8f83\u5feb\uff0citerator\u4e2d\u7684next()\u65b9\u6cd5\uff0c\u91c7\u7528\u7684\u5373\u662f\u987a\u5e8f\u8bbf\u95ee\u7684\u65b9\u6cd5\uff0c\u56e0\u6b64\u5728LinkedList\u91cc\uff0c\u4f7f\u7528iterator\u8f83\u5feb\u3002\n<\/p>\n

\n\tIterator
\n<\/h2>\n

\n\t\u5728Java\u96c6\u5408\u6846\u67b6\u4e2dIterator\u7528\u6765\u66ff\u4ee3Enumeration\uff0cIterator\u5141\u8bb8\u8c03\u7528\u8005\u5728\u8fed\u4ee3\u4e2d\u4ece\u5e95\u5c42\u96c6\u5408\u4e2d\u5220\u9664\u5143\u7d20\u3002\n<\/p>\n

\n\t\u63a5\u53e3\u65b9\u6cd5\u5982\u4e0b\uff1a\n<\/p>\n

\r\nboolean hasNext();\/\/\u5982\u679c\u8fed\u4ee3\u4e2d\u8fd8\u6709\u5143\u7d20\u8fd4\u56detrue\u3002\r\nObject\t next();\/\/\u8fd4\u56de\u8fed\u4ee3\u4e2d\u7684\u4e0b\u4e00\u4e2a\u5143\u7d20\u3002\r\nvoid\t remove();\/\/\u8fed\u4ee3\u5668\u4ece\u5e95\u5c42\u96c6\u5408\u4e2d\u5220\u9664\u521a\u8fd4\u56de\u7684\u5143\u7d20\u3002\u8be5\u65b9\u6cd5\u53ea\u80fd\u5728\u6bcf\u6b21\u8c03\u7528next\u540e\u8c03\u7528\u4e00\u6b21\u3002<\/pre>\n
\n\t\u5177\u4f53\u7528\u6cd5\u5982\u4e0b\uff1a\n<\/p>\n
\r\npublic class TestIterator { \r\n    public  static void main(String[] args) {\r\n        List list=new ArrayList();\r\n        Map map=new HashMap();\r\n        \/\/\u521d\u59cb\u5316list\u548cmap\u7684\u6570\u636e\r\n        for(int i=0;i<10;i++){\r\n            list.add(new String("list"+i) );\r\n            map.put(i, new String("map"+i));\r\n        } \r\n        Iterator iterList= list.iterator();\/\/List\u63a5\u53e3\u5b9e\u73b0\u4e86Iterable\u63a5\u53e3\r\n        \/\/\u5faa\u73aflist \r\n        while(iterList.hasNext()){\r\n             System.out.println((String)iterList.next());  \r\n        } \r\n        \/\/for each\u662fjdk5.0\u65b0\u589e\u52a0\u7684\u4e00\u4e2a\u5faa\u73af\u7ed3\u6784\uff0c\u53ef\u4ee5\u7528\u6765\u5904\u7406\u96c6\u5408\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u800c\u4e0d\u7528\u8003\u8651\u96c6\u5408\u5b9a\u4e0b\u6807\u3002\r\n        \/\/\u5982\u9700\u5220\u9664\u96c6\u5408\u5143\u7d20\uff0c\u614e\u7528\uff01\uff01\uff01\r\n        for(String str : list){\r\n            System.out.println(str);\r\n        }\r\n        Iterator iterMap=map.entrySet().iterator();\r\n        \/\/\u5faa\u73afmap\r\n        while(iterMap.hasNext()){\r\n            System.out.println((Map.Entry)iterMap.next().getValue());  \r\n        } \r\n    } \r\n}<\/pre>\n
\n\tEnumeration
\n<\/h2>\n
\n\t\u679a\u4e3e\u63a5\u53e3,\u5176\u4f5c\u7528\u548cIterator\u7c7b\u4f3c\u3002\u53ea\u63d0\u4f9b\u4e86\u904d\u5386Vector\u548cHashTable\u7c7b\u578b\u96c6\u5408\u5143\u7d20\u7684\u529f\u80fd\uff0c\u4e0d\u652f\u6301\u5143\u7d20\u7684\u79fb\u9664\u64cd\u4f5c\u3002\n<\/p>\n
\r\n\/\/\u662f\u5426\u8fd8\u6709\u5143\u7d20\uff0c\u5982\u679c\u6709\u8fd4\u56detrue\uff0c\u5426\u5219\u8868\u793a\u81f3\u5c11\u542b\u6709\u4e00\u4e2a\u5143\u7d20\r\nboolean hasMoreElements();\r\n\/\/\u5982\u679cEnumeration\u679a\u4e3e\u5bf9\u8c61\u8fd8\u6709\u5143\u7d20\uff0c\u8fd4\u56de\u5bf9\u8c61\u53ea\u80fd\u7684\u4e0b\u4e00\u4e2a\u5143\u7d20\uff0c\u5426\u5219\u629b\u51faNoSuchElementException\u5f02\u5e38\u3002\r\nE nextElement();<\/pre>\n
\n\t\u4f7f\u7528\u6559\u7a0b\u5982\u4e0b\uff1a\n<\/p>\n
\r\npublic class TestEnumeration{\r\n\tpublic static void main(String[] args){\r\n        \/\/\u521d\u59cb\u5316\u521b\u5efaVector\r\n        Vector v = new Vector();\r\n        v.addElement("Lisa");\r\n        v.addElement("Billy");\r\n        v.addElement("Mr Brown");\r\n        Enumeration e = v.elements();\/\/\u8fd4\u56deEnumeration\u5bf9\u8c61\r\n        while(e.hasMoreElements()){\r\n            String value = (String)e.nextElement();\/\/\u8c03\u7528nextElement\u65b9\u6cd5\u83b7\u5f97\u5143\u7d20\r\n            System.out.print(value);\r\n        }\r\n        \/\/\u521d\u59cb\u5316\u521b\u5efahashtable\r\n        Hashtable<String, String> ht = new Hashtable<String, String>();\r\n        for (int i = 0; i < 10000; i++) {\r\n            ht.put("Key=" + i, "Val=" + i);\r\n        }\r\n        \/\/1.Enumeration\r\n        Enumeration<String> en = ht.keys();\/\/\u4f7f\u7528\u679a\u4e3e\u83b7\u53d6key\r\n        \/\/\u4e0b\u9762\u7684\u4e5f\u53ef\u4ee5\u54e6\r\n        \/\/Enumeration<String> en = ht.elements();\/\/\u4f7f\u7528\u679a\u4e3e\u83b7\u53d6\u8fd9\u4e2akey-value\u5bf9\r\n        while (en.hasMoreElements()) {\r\n            System.out.print((String) en.nextElement());\r\n        }\r\n        \/\/2.Iterator \u8fed\u4ee3\u5668\r\n        \/\/\u4f7f\u7528\u8fed\u4ee3\u5668\u83b7\u53d6\u8fd9\u4e2akey-value\u5bf9\r\n        Iterator<Entry<String, String>> it1 = ht.entrySet().iterator();\r\n        \/\/\u4f7f\u7528\u8fed\u4ee3\u5668\u83b7\u53d6\u8fd9\u4e2akey\r\n        \/\/Iterator<String> it2 = ht.keySet().iterator();\r\n        while (it.hasNext()) {\r\n            \/\/System.out.print((Entry<String, String>) it1.next().getKey());\r\n            \/\/System.out.print((String) it2.next());\r\n        }\r\n    }\r\n}\r\n<\/pre>\n
\"\u4e1a\u4f59\u8349\u516c\u4f17\u53f7\"\/<\/p>
\u6700\u540e\uff0c\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u4e2a\u4eba\u5fae\u4fe1\u516c\u4f17\u53f7\uff1a\u4e1a\u4f59\u8349\uff08yyucao\uff09\uff01\u53ef\u52a0\u4f5c\u8005\u5fae\u4fe1\u53f7\uff1axttblog2<\/font>\u3002\u5907\u6ce8\uff1a\u201c1\u201d\uff0c\u6dfb\u52a0\u535a\u4e3b\u5fae\u4fe1\u62c9\u4f60\u8fdb\u5fae\u4fe1\u7fa4\u3002\u5907\u6ce8\u9519\u8bef\u4e0d\u4f1a\u540c\u610f\u597d\u53cb\u7533\u8bf7\u3002<\/b>\u518d\u6b21\u611f\u8c22\u60a8\u7684\u5173\u6ce8\uff01\u540e\u7eed\u6709\u7cbe\u5f69\u5185\u5bb9\u4f1a\u7b2c\u4e00\u65f6\u95f4\u53d1\u7ed9\u60a8\uff01\u539f\u521b\u6587\u7ae0\u6295\u7a3f\u8bf7\u53d1\u9001\u81f3532009913@qq.com\u90ae\u7bb1\u3002\u5546\u52a1\u5408\u4f5c\u4e5f\u53ef\u6dfb\u52a0\u4f5c\u8005\u5fae\u4fe1\u8fdb\u884c\u8054\u7cfb\uff01<\/p>
\u672c\u6587\u539f\u6587\u51fa\u5904\uff1a\u4e1a\u4f59\u8349<\/a>\uff1a » \u8be6\u89e3 Java \u4e2d\u7684 Iterable\u3001Itetator\u3001Enumeration<\/a><\/p>","protected":false},"excerpt":{"rendered":"
Java \u4e2d\u5bf9\u4e00\u4e9b\u96c6\u5408\u5faa\u73af\u904d\u5386\u505a\u4e86\u4e00\u4e9b\u7279\u6b8a\u7684\u5c01\u88c5\u3002\u4e00\u4e9b\u662f\u65b9\u4fbf\u6211\u4eec\u7684\u64cd\u4f5c\uff0c\u4e00\u4e9b\u662f\u5b58\u5728\u5b58\u50a8\u6027\u80fd\u7b49\u65b9\u9762\u8bbe\u8ba1\u7684\u3002\u5173\u4e8e  […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[462,978,1161,69,1163],"class_list":["post-2746","post","type-post","status-publish","format-standard","hentry","category-java","tag-hashcodebuilder","tag-hashedcredentialsmatcher","tag-hashmap","tag-java","tag-linkedhashmap"],"_links":{"self":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/2746","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2746"}],"version-history":[{"count":1,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/2746\/revisions"}],"predecessor-version":[{"id":2747,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/2746\/revisions\/2747"}],"wp:attachment":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2746"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2746"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2746"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}