{"id":2556,"date":"2013-12-12T13:37:04","date_gmt":"2013-12-12T04:37:04","guid":{"rendered":"https:\/\/www.united-bears.co.jp\/blog\/?p=2556"},"modified":"2013-12-12T13:37:04","modified_gmt":"2013-12-12T04:37:04","slug":"java-%e3%81%a7%e3%83%aa%e3%82%b9%e3%83%88%e3%82%92%e3%83%9e%e3%83%83%e3%83%97%e3%81%ab%e5%a4%89%e6%8f%9b%e3%81%99%e3%82%8b","status":"publish","type":"post","link":"https:\/\/www.united-bears.co.jp\/blog\/archives\/2556","title":{"rendered":"Java \u3067\u30ea\u30b9\u30c8\u3092\u30de\u30c3\u30d7\u306b\u5909\u63db\u3059\u308b"},"content":{"rendered":"<p>\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u304b\u3089\u53d6\u5f97\u3057\u305f\u30c7\u30fc\u30bf\u306f\u3001\u72ec\u81ea\u30af\u30e9\u30b9\u304b java.util.Map \u306e\u30ea\u30b9\u30c8\u306e\u5f62\u306b\u306a\u3063\u3066\u3044\u308b\u5834\u5408\u304c\u591a\u3044\u3002User \u3068\u3044\u3046\u30af\u30e9\u30b9\u3092\u5b9a\u7fa9\u3057\u3066\u304a\u304d\u3001\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u304b\u3089\u53d6\u5f97\u3057\u305f\u30c7\u30fc\u30bf\u3092 User \u30af\u30e9\u30b9\u306e\u30d5\u30a3\u30fc\u30eb\u30c9\u306e\u5024\u3068\u3057\u3066\u30bb\u30c3\u30c8\u3059\u308b\u5834\u5408\u3092\u4f8b\u306b\u8003\u3048\u3066\u307f\u308b\u3002<\/p>\n<pre>\r\npublic class User implements Serializable {\r\n       private long userId;\r\n       private String firstName;\r\n       private String lastName;\r\n...\r\n}\r\n<\/pre>\n<pre>\r\nList&lt;User&gt; users = dao.list();\r\n<\/pre>\n<p>\u53d6\u5f97\u3057\u305f\u30c7\u30fc\u30bf\u306f\u3001java.util.List \u306b\u8907\u6570\u306e User \u3092\u683c\u7d0d\u3057\u305f\u5f62\u306b\u306a\u308b\u304c\u3001userId \u3092\u30ad\u30fc\u306b\u3057\u305f java.util.Map \u306b\u5909\u63db\u3059\u308b\u3053\u3068\u304c\u591a\u3044\u3002java.util.Map \u30a4\u30f3\u30bf\u30d5\u30a7\u30fc\u30b9\u3092\u5b9f\u88c5\u3057\u305f\u30af\u30e9\u30b9\u306e\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u751f\u6210\u3057\u3066\u3001java.util.List \u3092\u30eb\u30fc\u30d7\u3067\u56de\u3057\u3066\u30bb\u30c3\u30c8\u3057\u3066\u3082\u3088\u3044\u306e\u3060\u304c\u3001\u540c\u3058\u3088\u3046\u306a\u30b3\u30fc\u30c9\u3092\u4f55\u5ea6\u3082\u66f8\u304f\u306e\u306f\u9762\u5012\u306a\u306e\u3067\u3001Generics  \u3068 java.beans.PropertyDescriptor \u3092\u4f7f\u3063\u305f\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\u3092\u4f5c\u6210\u3057\u3066\u307f\u305f\u3002<\/p>\n<pre>\r\npublic static &lt;K, V&gt; Map&lt;K, V&gt; toMap(Collection&lt;V&gt; c, String field)\r\n        throws IntrospectionException, IllegalAccessException,\r\n        IllegalArgumentException, InvocationTargetException {\r\n\r\n    Map&lt;K, V&gt; m = new LinkedHashMap&lt;K, V&gt;();\r\n    for (V v : c) {\r\n        PropertyDescriptor pd = new PropertyDescriptor(field, v.getClass());\r\n        K k = (K) pd.getReadMethod().invoke(v, (Object[]) null);\r\n        m.put(k, v);\r\n    }\r\n    return m;\r\n\r\n}\r\n<\/pre>\n<p>\u4f7f\u3044\u65b9\u306f\u7c21\u5358\u3067\u3001\u5909\u63db\u3057\u305f\u3044\u30ea\u30b9\u30c8(java.util.Collection \u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u3092\u5b9f\u88c5\u3057\u3066\u3044\u308c\u3070\u3088\u3044)\u3068\u3001\u30ad\u30fc\u306b\u3059\u308b\u30d5\u30a3\u30fc\u30eb\u30c9\u540d(java.lang.String)\u3092\u5f15\u6570\u3068\u3057\u3066\u4e0e\u3048\u308c\u3070\u3088\u3044\u3002<\/p>\n<pre>\r\nList<User> users = dao.list();\r\nMap<Long, User> map = Utils.<Long, User> toMap(user, \"sectionGroupId\");\r\n<\/pre>\n<p>Generics \u3092\u5229\u7528\u3057\u305f\u3053\u3068\u306b\u3088\u308a\u3001\u751f\u6210\u3059\u308b Map \u3067\u5229\u7528\u3059\u308b\u30ad\u30fc\u3068\u5024\u3092\u6307\u5b9a\u3067\u304d\u3066\u7d50\u69cb\u4fbf\u5229\u3060\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u304b\u3089\u53d6\u5f97\u3057\u305f\u30c7\u30fc\u30bf\u306f\u3001\u72ec\u81ea\u30af\u30e9\u30b9\u304b java.util.Map \u306e\u30ea\u30b9\u30c8\u306e\u5f62\u306b\u306a\u3063\u3066\u3044\u308b\u5834\u5408\u304c\u591a\u3044\u3002User \u3068\u3044\u3046\u30af\u30e9\u30b9\u3092\u5b9a\u7fa9\u3057\u3066\u304a\u304d\u3001\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u304b\u3089\u53d6\u5f97\u3057\u305f\u30c7\u30fc\u30bf\u3092 User \u30af\u30e9\u30b9\u306e\u30d5\u30a3\u30fc\u30eb\u30c9\u306e\u5024\u3068\u3057 [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[41,40],"tags":[],"class_list":["post-2556","post","type-post","status-publish","format-standard","hentry","category-java-","category-40"],"_links":{"self":[{"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/posts\/2556","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/comments?post=2556"}],"version-history":[{"count":6,"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/posts\/2556\/revisions"}],"predecessor-version":[{"id":2562,"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/posts\/2556\/revisions\/2562"}],"wp:attachment":[{"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/media?parent=2556"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/categories?post=2556"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.united-bears.co.jp\/blog\/wp-json\/wp\/v2\/tags?post=2556"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}