{"id":585,"date":"2021-02-05T17:31:06","date_gmt":"2021-02-05T09:31:06","guid":{"rendered":"https:\/\/www.52dixiaowo.com\/java\/?p=585"},"modified":"2021-02-05T20:13:18","modified_gmt":"2021-02-05T12:13:18","slug":"map-%e6%8e%a5%e5%8f%a3","status":"publish","type":"post","link":"https:\/\/www.52dixiaowo.com\/java\/post-585.html","title":{"rendered":"Map \u63a5\u53e3"},"content":{"rendered":"\n<p>Map \u96c6\u5408\u662f\u4e00\u4e2a\u53cc\u5217\u96c6\u5408\uff0c\u5305\u542b1\u4e2a key, 1\u4e2a value<\/p>\n\n\n\n<p>Map \u96c6\u5408\u4e2d\u7684\u5143\u7d20, key, value \u53ef\u4ee5\u662f\u76f8\u540c\uff0c\u6216\u4e0d\u540c\u7c7b\u578b\u7684<\/p>\n\n\n\n<p>key \u662f\u4e0d\u5141\u8bb8\u91cd\u590d\u7684, value \u5141\u8bb8\u91cd\u590d<\/p>\n\n\n\n<p>key \u4e0e value \u662f\u4e00\u4e00\u5bf9\u5e94\u5173\u7cfb<\/p>\n\n\n\n<h5>1.\u5bfc\u5305<\/h5>\n\n\n\n<pre class=\"wp-block-code\"><code>java.util.Map;<\/code><\/pre>\n\n\n\n<h5>2.\u6784\u9020\u65b9\u6cd5<\/h5>\n\n\n\n<p>\u4f7f\u7528\u591a\u6001\u521b\u5efa\u5b50\u7c7b\u5b9e\u73b0\u7c7b<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Map&lt;String,String&gt; map = new HashMap&lt;&gt;();<\/code><\/pre>\n\n\n\n<h5>3.\u65b9\u6cd5<\/h5>\n\n\n\n<p>1.\u6dfb\u52a0\u5143\u7d20<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/1.\u6dfb\u52a0\u5143\u7d20\nString m1 = map.put(\"\u6c34\u6d52\u4f20\",\"\u65bd\u8010\u5eb5\");\nmap.put(\"\u4e09\u56fd\u6f14\u4e49\",\"\u7f57\u8d2f\u4e2d\");\nmap.put(\"\u4e09\u56fd\u6f14\u4e492\",\"\u7f57\u8d2f\u4e2d\");\nString m3 = map.put(\"\u6c34\u6d52\u4f20\",\"\u65bd\u8010\u5eb52\");\/\/ key \u91cd\u590d\u65f6\uff0c\u4f1a\u81ea\u52a8\u8986\u76d6\n\/\/\u6dfb\u52a0\u7684 key \u4e3a\u7a7a\u65f6,\u8fd4\u56denull\uff0c\u5426\u5219\u8fd4\u56de value\nSystem.out.println(\"m1\uff1a\"+m1+\",m3\uff1a\"+m3);\nSystem.out.println(map);<\/code><\/pre>\n\n\n\n<p>2.\u5220\u9664\u5143\u7d20<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/2.\u5220\u9664\u5143\u7d20\nString s4 = map.remove(\"\u897f\u6e38\u8bb0\"); \/\/\u6ca1\u6709\u6b64 key \uff0c\u8fd4\u56de null\nString s5 = map.remove(\"\u6c34\u6d52\u4f20\"); \/\/\u5220\u9664\u6c34\u6d52\u4f20\uff0c\u8fd4\u56de\u88ab\u5220\u9664\u7684\u503c\nSystem.out.println(\"s4\uff1a\"+s4+\",s5\uff1a\"+s5);\nSystem.out.println(map);<\/code><\/pre>\n\n\n\n<p>3.\u83b7\u53d6 value<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/3.\u83b7\u53d6\u5143\u7d20\nString s6 = map.get(\"\u6c34\u6d52\u4f20\");  \/\/\u6ca1\u6709\u6b64 key\uff0c\u8fd4\u56de null\nString s7 = map.get(\"\u4e09\u56fd\u6f14\u4e49\");   \/\/\u5b58\u5728\u6b64 key\uff0c\u8fd4\u56de value\nSystem.out.println(\"s6\uff1a\"+s6+\",s7\uff1a\"+s7);<\/code><\/pre>\n\n\n\n<p>4.\u67e5\u8be2\u662f\u5426\u5305\u542b\u5143\u7d20<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/4.\u67e5\u8be2\u662f\u5426\u5305\u542b\u5143\u7d20\nboolean b1 = map.containsKey(\"\u7ea2\u697c\u68a6\"); \/\/\u6ca1\u6709\u6b64 key\uff0c\u8fd4\u56de null\nboolean b2 = map.containsKey(\"\u4e09\u56fd\u6f14\u4e49\"); \/\/\u5b58\u5728\u6b64 key\uff0c\u8fd4\u56de value\nSystem.out.println(\"b1\uff1a\"+b1+\",b2\uff1a\"+b2);<\/code><\/pre>\n\n\n\n<p>5.\u904d\u5386 map \u96c6\u5408<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/5.1 -&gt; keySet \u904d\u5386\nSet&lt;String&gt; set = map.keySet();  \/\/1.\u5f97\u5230\u6240\u6709\u7684 key\nfor(String key : set){  \/\/2.\u4f7f\u7528\u589e\u5f3a for \u904d\u5386 key\n  String value = map.get(key);  \/\/3.\u4f7f\u7528 get \u65b9\u6cd5\u83b7\u53d6 value\n  System.out.println(key+\"=\"+value);\n}\n\/\/5.2 -&gt; entrySet \u904d\u5386\nSet&lt;Map.Entry&lt;String,String&gt;&gt; set2 = map.entrySet(); \/\/1.\u83b7\u53d6\u6240\u6709\u7684 entry \u5bf9\u8c61\nfor(Map.Entry&lt;String,String&gt; entry : set2){ \/\/2.\u4f7f\u7528\u589e\u5f3a for \u904d\u5386 entry\n  String key = entry.getKey();  \/\/3.\u53d6\u5f97 key\n  String value = entry.getValue(); \/\/4.\u53d6\u5f97 value\n  System.out.println(key+\"=\"+value);\n}<\/code><\/pre>\n\n\n\n<h5>4.\u6ce8\u610f\u4e8b\u9879<\/h5>\n\n\n\n<p>Map \u63a5\u53e3\u7684\u552f\u4e00\u76f4\u63a5\u5b50\u7c7b AbstractMap<\/p>\n\n\n\n<p>\u8be5\u62bd\u8c61\u7c7b\u4e2d\u63d0\u4f9b\u4e86\u5f88\u591a\u5171\u6027\u65b9\u6cd5\uff0c\u5e76\u91cd\u5199\u4e86 toString()\u65b9\u6cd5<\/p>\n\n\n\n<p>\u76f4\u63a5\u6253\u5370 Map \u53ca\u5176\u5b50\u7c7b\u7684\u96c6\u5408\u65f6\uff0c\u4ee5 key=value \u663e\u793a\uff0c\u4e3a\u7a7a\u65f6\u663e\u793a {}<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Map \u96c6\u5408\u662f\u4e00\u4e2a\u53cc\u5217\u96c6\u5408\uff0c\u5305\u542b1\u4e2a key, 1\u4e2a value Map \u96c6\u5408\u4e2d\u7684\u5143\u7d20, key, value&hellip; <a href=\"https:\/\/www.52dixiaowo.com\/java\/post-585.html\" class=\"more-link\">\u7ee7\u7eed\u9605\u8bfb <span class=\"screen-reader-text\">Map \u63a5\u53e3<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[14],"tags":[],"_links":{"self":[{"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/posts\/585"}],"collection":[{"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/comments?post=585"}],"version-history":[{"count":0,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/posts\/585\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/media?parent=585"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/categories?post=585"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/tags?post=585"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}