{"id":1257,"date":"2022-10-28T22:58:39","date_gmt":"2022-10-28T14:58:39","guid":{"rendered":"https:\/\/qaqaq.top\/?p=1257"},"modified":"2022-11-27T12:39:47","modified_gmt":"2022-11-27T04:39:47","slug":"%e6%b3%9b%e5%9e%8b%e4%b8%8efile-%e4%b8%ba%e4%bb%80%e4%b9%88%e8%a6%81%e4%bd%bf%e7%94%a8%e6%b3%9b%e5%9e%8b%e3%80%81%e6%b3%9b%e5%9e%8b%e4%b8%8efile%e4%b8%ad%e4%bd%bf%e7%94%a8%e6%b3%9b%e5%9e%8b%e4%b8%be","status":"publish","type":"post","link":"https:\/\/qaqaq.top\/?p=1257","title":{"rendered":"\u6cdb\u578b\u4e0eFile-\u4e3a\u4ec0\u4e48\u8981\u4f7f\u7528\u6cdb\u578b\u3001\u6cdb\u578b\u4e0eFile\u4e2d\u4f7f\u7528\u6cdb\u578b\u4e3e\u4f8b"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code>package top.qaqaq.java.P565;\r\n\r\nimport org.junit.jupiter.api.Test;\r\n\r\nimport java.util.*;\r\n\/\/import java.util.Map.*;\r\n\r\n\/**\r\n * \u6cdb\u578b\u7684\u4f7f\u7528\r\n * 1. jdk 5.0\u65b0\u589e\u7684\u7279\u6027\r\n *\r\n * 2. \u5728\u96c6\u5408\u4e2d\u4f7f\u7528\u6cdb\u578b\uff1a\r\n *  \u603b\u7ed3\uff1a\r\n *  \u2460 \u96c6\u5408\u63a5\u53e3\u6216\u96c6\u5408\u7c7b\u5728jdk5.0\u65f6\u90fd\u4fee\u6539\u4e3a\u5e26\u6cdb\u578b\u7684\u7ed3\u6784\u3002\r\n *  \u2461 \u5728\u5b9e\u4f8b\u5316\u96c6\u5408\u7c7b\u65f6\uff0c\u53ef\u4ee5\u6307\u660e\u5177\u4f53\u7684\u6cdb\u578b\u7c7b\u578b\r\n *  \u2462 \u6307\u660e\u5b8c\u4ee5\u540e\uff0c\u5728\u96c6\u5408\u7c7b\u6216\u63a5\u53e3\u4e2d\u51e1\u662f\u5b9a\u4e49\u7c7b\u6216\u63a5\u53e3\u65f6\uff0c\u5185\u90e8\u7ed3\u6784\uff08\u6bd4\u5982\uff1a\u65b9\u6cd5\u3001\u6784\u9020\u5668\u3001\u5c5e\u6027\u7b49\uff09\u4f7f\u7528\u5230\u7c7b\u7684\u6cdb\u578b\u7684\u4f4d\u7f6e\uff0c\u90fd\u6307\u5b9a\u4e3a\u5b9e\u4f8b\u5316\u7684\u6cdb\u578b\u7c7b\u578b\u3002\r\n *      \u6bd4\u5982\uff1aadd(E e) --->\u5b9e\u4f8b\u5316\u4ee5\u540e\uff1aadd(Integer e)\r\n *  \u2463 \u6ce8\u610f\u70b9\uff1a\u6cdb\u578b\u7684\u7c7b\u578b\u5fc5\u987b\u662f\u7c7b\uff0c\u4e0d\u80fd\u662f\u57fa\u672c\u6570\u636e\u7c7b\u578b\u3002\u9700\u8981\u7528\u5230\u57fa\u672c\u6570\u636e\u7c7b\u578b\u7684\u4f4d\u7f6e\uff0c\u62ff\u5305\u88c5\u7c7b\u66ff\u6362\r\n *  \u2464 \u5982\u679c\u5b9e\u4f8b\u5316\u65f6\uff0c\u6ca1\u6709\u6307\u660e\u6cdb\u578b\u7684\u7c7b\u578b\u3002\u9ed8\u8ba4\u7c7b\u578b\u4e3ajava.lang.Object\u7c7b\u578b\u3002\r\n *\r\n * 3. \u5982\u4f55\u81ea\u5b9a\u4e49\u6cdb\u578b\u7ed3\u6784\uff1a\u6cdb\u578b\u7c7b\u3001\u6cdb\u578b\u63a5\u53e3\uff1a\u6cdb\u578b\u65b9\u6cd5\u3002\u89c1 GenericTest1.java\r\n *\r\n * @author RichieZhang\r\n * @create 2022-10-28 \u4e0b\u5348 3:03\r\n *\/\r\npublic class GenericTest {\r\n\r\n    \/\/\u5728\u96c6\u5408\u4e2d\u4f7f\u7528\u6cdb\u578b\u4e4b\u524d\u7684\u60c5\u51b5\r\n    @Test\r\n    public void test1(){\r\n        ArrayList list = new ArrayList();\r\n        \/\/\u9700\u6c42\uff1a\u5b58\u653e\u5b66\u751f\u7684\u6210\u7ee9\r\n        list.add(78);\r\n        list.add(76);\r\n        list.add(89);\r\n        list.add(88);\r\n        \/\/\u95ee\u9898\u4e00\uff1a\u7c7b\u578b\u4e0d\u5b89\u5168\r\n\/\/        list.add(\"Tom\");\r\n\r\n        for (Object score : list) {\r\n            \/\/\u95ee\u9898\u4e8c\uff1a\u5f3a\u8f6c\u65f6\uff0c\u53ef\u80fd\u51fa\u73b0ClassCastException\r\n            int stuScore = (Integer) score;\r\n\r\n            System.out.println(stuScore);\r\n        }\r\n\r\n    }\r\n\r\n    \/\/\u5728\u96c6\u5408\u4e2d\u4f7f\u7528\u6cdb\u578b\u7684\u60c5\u51b5\uff1a\u4ee5ArrayList\r\n    @Test\r\n    public void test2(){\r\n        ArrayList&lt;Integer> list = new ArrayList&lt;Integer>();\r\n\r\n        list.add(78);\r\n        list.add(87);\r\n        list.add(99);\r\n        list.add(65);\r\n        \/\/\u7f16\u8bd1\u65f6\uff0c\u5c31\u4f1a\u8fdb\u884c\u7c7b\u578b\u68c0\u67e5\uff0c\u4fdd\u8bc1\u6570\u636e\u7684\u5b89\u5168\r\n\/\/        list.add(\"Tom\");\r\n\r\n        \/\/\u65b9\u5f0f\u4e00\uff1a\r\n\/\/        for (Integer score : list){\r\n\/\/            \/\/\u907f\u514d\u4e86\u5f3a\u8f6c\u64cd\u4f5c\r\n\/\/            int stuScore = score;\r\n\/\/\r\n\/\/            System.out.println(stuScore);\r\n\/\/        }\r\n\r\n       \/\/\u65b9\u5f0f\u4e8c\uff1a\r\n        Iterator&lt;Integer> iterator = list.iterator();\r\n        while (iterator.hasNext()){\r\n            int stuScore = iterator.next();\r\n            System.out.println(stuScore);\r\n        }\r\n    }\r\n\r\n    \/\/\u5728\u96c6\u5408\u4e2d\u4f7f\u7528\u6cdb\u578b\u7684\u60c5\u51b5\uff1a\u4ee5HashMap\u4e3a\u4f8b\r\n    @Test\r\n    public void test3(){\r\n\/\/        Map&lt;String,Integer> map = new HashMap&lt;String,Integer>();\r\n        \/\/jdk7\u65b0\u7279\u6027\uff1a\u7c7b\u578b\u63a8\u65ad\r\n        Map&lt;String,Integer> map = new HashMap&lt;>();\r\n\r\n        map.put(\"Tom\",87);\r\n        map.put(\"Jerry\",87);\r\n        map.put(\"Jack\",67);\r\n\r\n\/\/        map.put(123,\"ABC\");\r\n        \/\/\u6cdb\u578b\u7684\u5d4c\u5957\r\n        Set&lt;Map.Entry&lt;String,Integer>> entry =  map.entrySet();\r\n        Iterator&lt;Map.Entry&lt;String, Integer>> iterator = entry.iterator();\r\n\r\n        while (iterator.hasNext()){\r\n            Map.Entry&lt;String, Integer> e = iterator.next();\r\n            String key = e.getKey();\r\n            Integer value = e.getValue();\r\n            System.out.println(key + \"----\" + value);\r\n\r\n        }\r\n\r\n    }\r\n\r\n}\r\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[46],"class_list":["post-1257","post","type-post","status-publish","format-standard","hentry","category-java-code","tag-java"],"_links":{"self":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1257"}],"collection":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1257"}],"version-history":[{"count":1,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1257\/revisions"}],"predecessor-version":[{"id":1258,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1257\/revisions\/1258"}],"wp:attachment":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1257"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1257"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1257"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}