{"provider_name":"Hatena Blog","author_url":"https://blog.hatena.ne.jp/waritohutsu/","url":"https://normalian.hatenablog.com/entry/20080520","height":"190","image_url":null,"html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fnormalian.hatenablog.com%2Fentry%2F20080520\" title=\"\u6c38\u7d9a\u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u95a2\u9023\u306b\u3064\u3044\u3066 - normalian blog\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","blog_title":"normalian blog","categories":[],"version":"1.0","published":"2008-05-20 00:00:00","blog_url":"https://normalian.hatenablog.com/","author_name":"waritohutsu","provider_url":"https://hatena.blog","title":"\u6c38\u7d9a\u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u95a2\u9023\u306b\u3064\u3044\u3066","width":"100%","type":"rich","description":"JPA \u3092\u5229\u7528\u3059\u308b\u5834\u5408\u3001\u6c38\u7d9a\u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u3068\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u63a5\u7d9a\u60c5\u5831\u306f persistence.xml\u306b\u8a18\u8ff0\u3059\u308b\u3002 persistence.xml\u4e0a\u3067\u3001\u6c38\u7d9a\u30e6\u30cb\u30c3\u30c8\u3068\u3044\u3046\u5358\u4f4d\u3067\u7ba1\u7406\u3055\u308c\u3066\u3044\u308b EntityManager\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u3092\u7528\u3044\u3066\u6c38\u7d9a\u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u306b\u30a2\u30af\u30bb\u30b9\u30fb\u7ba1\u7406\u3059\u308b EntityManager.find\u2026\u4e3b\u30ad\u30fc\u306b\u3088\u3063\u3066\u30a8\u30f3\u30c6\u30a3\u30c6\u30a3\u3092\u691c\u7d22\u3059\u308b\u3002\u898b\u3064\u304b\u3089\u306a\u304b\u3063\u305f\u3089null\u3092\u8fd4\u3059 \u4f8b\uff09User user = em.find( .class, ); EntityManager.createQuery\u2026\u691c\u7d22\u306e\u70ba\u306eQuery\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u751f\u6210\u3059\u308b"}