{"id":62023,"date":"2024-10-13T15:34:18","date_gmt":"2024-10-13T07:34:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/62023\/"},"modified":"2024-10-13T15:34:18","modified_gmt":"2024-10-13T07:34:18","slug":"java%e5%af%a6%e7%8f%be%e9%ab%98%e6%95%88%e5%a4%9a%e8%a1%a8%e6%9f%a5%e8%a9%a2%ef%bc%9a%e9%80%a3%e6%8e%a5%e6%95%b8%e6%93%9a%e5%ba%ab%e6%8a%80%e5%b7%a7-java%e9%80%a3%e6%8e%a5%e6%95%b8%e6%93%9a%e5%ba%ab","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/62023\/","title":{"rendered":"Java\u5be6\u73fe\u9ad8\u6548\u591a\u8868\u67e5\u8a62\uff1a\u9023\u63a5\u6578\u64da\u5eab\u6280\u5de7 (java\u9023\u63a5\u6578\u64da\u5eab\u591a\u8868\u67e5\u8a62)"},"content":{"rendered":"<h1 id=\"java%e5%af%a6%e7%8f%be%e9%ab%98%e6%95%88%e5%a4%9a%e8%a1%a8%e6%9f%a5%e8%a9%a2%ef%bc%9a%e9%80%a3%e6%8e%a5%e6%95%b8%e6%93%9a%e5%ba%ab%e6%8a%80%e5%b7%a7-FnZvtSkoTG\">Java\u5be6\u73fe\u9ad8\u6548\u591a\u8868\u67e5\u8a62\uff1a\u9023\u63a5\u6578\u64da\u5eab\u6280\u5de7<\/h1>\n<p>\u5728\u7576\u4eca\u7684\u61c9\u7528\u958b\u767c\u4e2d\uff0c\u6578\u64da\u5eab\u7684\u4f7f\u7528\u5df2\u6210\u70ba\u4e0d\u53ef\u6216\u7f3a\u7684\u4e00\u90e8\u5206\u3002\u5c24\u5176\u662f\u5728Java\u958b\u767c\u4e2d\uff0c\u5982\u4f55\u9ad8\u6548\u5730\u9032\u884c\u591a\u8868\u67e5\u8a62\u662f\u6bcf\u4f4d\u958b\u767c\u8005\u5fc5\u9808\u638c\u63e1\u7684\u6280\u80fd\u3002\u672c\u6587\u5c07\u63a2\u8a0eJava\u9023\u63a5\u6578\u64da\u5eab\u9032\u884c\u591a\u8868\u67e5\u8a62\u7684\u6280\u5de7\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u63d0\u5347\u67e5\u8a62\u6548\u7387\u3002<\/p>\n<h2 id=\"%e5%a4%9a%e8%a1%a8%e6%9f%a5%e8%a9%a2%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-FnZvtSkoTG\">\u591a\u8868\u67e5\u8a62\u7684\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>\u591a\u8868\u67e5\u8a62\u662f\u6307\u5728\u4e00\u500bSQL\u67e5\u8a62\u4e2d\u540c\u6642\u5f9e\u591a\u500b\u8868\u4e2d\u6aa2\u7d22\u6578\u64da\u3002\u9019\u901a\u5e38\u6d89\u53ca\u5230\u4f7f\u7528JOIN\u8a9e\u53e5\u4f86\u9023\u63a5\u4e0d\u540c\u7684\u8868\u3002\u6839\u64da\u9700\u6c42\u7684\u4e0d\u540c\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u9078\u64c7\u4e0d\u540c\u985e\u578b\u7684JOIN\uff0c\u5982INNER JOIN\u3001LEFT JOIN\u3001RIGHT JOIN\u7b49\u3002<\/p>\n<h3 id=\"join%e7%9a%84%e9%a1%9e%e5%9e%8b-FnZvtSkoTG\">JOIN\u7684\u985e\u578b<\/h3>\n<ul>\n<li><strong>INNER JOIN<\/strong>: \u53ea\u8fd4\u56de\u5169\u500b\u8868\u4e2d\u5339\u914d\u7684\u884c\u3002<\/li>\n<li><strong>LEFT JOIN<\/strong>: \u8fd4\u56de\u5de6\u8868\u7684\u6240\u6709\u884c\uff0c\u5373\u4f7f\u53f3\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\u3002<\/li>\n<li><strong>RIGHT JOIN<\/strong>: \u8fd4\u56de\u53f3\u8868\u7684\u6240\u6709\u884c\uff0c\u5373\u4f7f\u5de6\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\u3002<\/li>\n<li><strong>FULL OUTER JOIN<\/strong>: \u8fd4\u56de\u5169\u500b\u8868\u4e2d\u6240\u6709\u7684\u884c\uff0c\u7121\u8ad6\u662f\u5426\u6709\u5339\u914d\u3002<\/li>\n<\/ul>\n<h2 id=\"java%e9%80%a3%e6%8e%a5%e6%95%b8%e6%93%9a%e5%ba%ab%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%ad%a5%e9%a9%9f-FnZvtSkoTG\">Java\u9023\u63a5\u6578\u64da\u5eab\u7684\u57fa\u672c\u6b65\u9a5f<\/h2>\n<p>\u5728Java\u4e2d\u9023\u63a5\u6578\u64da\u5eab\u7684\u904e\u7a0b\u901a\u5e38\u5305\u62ec\u4ee5\u4e0b\u5e7e\u500b\u6b65\u9a5f\uff1a<\/p>\n<ol>\n<li>\u52a0\u8f09JDBC\u9a45\u52d5\u7a0b\u5e8f\u3002<\/li>\n<li>\u5efa\u7acb\u6578\u64da\u5eab\u9023\u63a5\u3002<\/li>\n<li>\u5275\u5efaStatement\u6216PreparedStatement\u5c0d\u8c61\u3002<\/li>\n<li>\u57f7\u884cSQL\u67e5\u8a62\u3002<\/li>\n<li>\u8655\u7406\u7d50\u679c\u96c6\u3002<\/li>\n<li>\u95dc\u9589\u9023\u63a5\u3002<\/li>\n<\/ol>\n<h3 id=\"%e7%a4%ba%e4%be%8b%e4%bb%a3%e7%a2%bc-FnZvtSkoTG\">\u793a\u4f8b\u4ee3\u78bc<\/h3>\n<pre><code>import java.sql.Connection;\nimport java.sql.DriverManager;\nimport java.sql.ResultSet;\nimport java.sql.Statement;\n\npublic class MultiTableQuery {\n    public static void main(String[] args) {\n        Connection conn = null;\n        Statement stmt = null;\n        ResultSet rs = null;\n\n        try {\n            \/\/ \u52a0\u8f09JDBC\u9a45\u52d5\u7a0b\u5e8f\n            Class.forName(\"com.mysql.cj.jdbc.Driver\");\n            \/\/ \u5efa\u7acb\u6578\u64da\u5eab\u9023\u63a5\n            conn = DriverManager.getConnection(\"jdbc:mysql:\/\/localhost:3306\/yourdatabase\", \"username\", \"password\");\n            \/\/ \u5275\u5efaStatement\u5c0d\u8c61\n            stmt = conn.createStatement();\n            \/\/ \u57f7\u884c\u591a\u8868\u67e5\u8a62\n            String sql = \"SELECT a.column1, b.column2 FROM tableA a INNER JOIN tableB b ON a.id = b.a_id\";\n            rs = stmt.executeQuery(sql);\n            \/\/ \u8655\u7406\u7d50\u679c\u96c6\n            while (rs.next()) {\n                System.out.println(\"Column1: \" + rs.getString(\"column1\") + \", Column2: \" + rs.getString(\"column2\"));\n            }\n        } catch (Exception e) {\n            e.printStackTrace();\n        } finally {\n            \/\/ \u95dc\u9589\u9023\u63a5\n            try { if (rs != null) rs.close(); } catch (Exception e) { e.printStackTrace(); }\n            try { if (stmt != null) stmt.close(); } catch (Exception e) { e.printStackTrace(); }\n            try { if (conn != null) conn.close(); } catch (Exception e) { e.printStackTrace(); }\n        }\n    }\n}\n<\/code><\/pre>\n<h2 id=\"%e6%8f%90%e9%ab%98%e6%9f%a5%e8%a9%a2%e6%95%88%e7%8e%87%e7%9a%84%e6%8a%80%e5%b7%a7-FnZvtSkoTG\">\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u7684\u6280\u5de7<\/h2>\n<p>\u5728\u9032\u884c\u591a\u8868\u67e5\u8a62\u6642\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u63a1\u53d6\u4ee5\u4e0b\u5e7e\u7a2e\u65b9\u6cd5\u4f86\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\uff1a<\/p>\n<ul>\n<li><strong>\u4f7f\u7528\u7d22\u5f15<\/strong>: \u70ba\u7d93\u5e38\u67e5\u8a62\u7684\u5217\u5275\u5efa\u7d22\u5f15\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u901f\u5ea6\u3002<\/li>\n<li><strong>\u907f\u514dSELECT *<\/strong>: \u53ea\u9078\u64c7\u9700\u8981\u7684\u5217\uff0c\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u91cf\u3002<\/li>\n<li><strong>\u4f7f\u7528PreparedStatement<\/strong>: \u9019\u4e0d\u50c5\u53ef\u4ee5\u63d0\u9ad8\u6027\u80fd\uff0c\u9084\u80fd\u9632\u6b62SQL\u6ce8\u5165\u653b\u64ca\u3002<\/li>\n<li><strong>\u5408\u7406\u8a2d\u8a08\u6578\u64da\u5eab\u7d50\u69cb<\/strong>: \u78ba\u4fdd\u6578\u64da\u5eab\u7684\u6b63\u898f\u5316\uff0c\u6e1b\u5c11\u5197\u9918\u6578\u64da\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-FnZvtSkoTG\">\u7e3d\u7d50<\/h2>\n<p>\u5728Java\u4e2d\u5be6\u73fe\u9ad8\u6548\u7684\u591a\u8868\u67e5\u8a62\u9700\u8981\u638c\u63e1\u57fa\u672c\u7684SQL\u8a9e\u6cd5\u548c\u6578\u64da\u5eab\u9023\u63a5\u6280\u5de7\u3002\u901a\u904e\u5408\u7406\u4f7f\u7528JOIN\u8a9e\u53e5\u3001\u7d22\u5f15\u4ee5\u53caPreparedStatement\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u5eab\u548c\u670d\u52d9\u5668\u74b0\u5883\u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u4e86\u89e3\u66f4\u591a\u95dc\u65bc<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u548c<a href=\"https:\/\/server.hk\">\u96f2\u670d\u52d9\u5668<\/a>\u7684\u8cc7\u8a0a\uff0c\u5c07\u6709\u52a9\u65bc\u63d0\u5347\u60a8\u7684\u61c9\u7528\u6027\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22Java\u4e2d\u9ad8\u6548\u591a\u8868\u67e5\u8a62\u7684\u6280\u5de7\uff0c\u638c\u63e1\u9023\u63a5\u6578\u64da\u5eab\u7684\u6700\u4f73\u5be6\u8e10\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u6027\u80fd\u8207\u6548\u7387\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-62023","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/62023","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=62023"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/62023\/revisions"}],"predecessor-version":[{"id":62024,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/62023\/revisions\/62024"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=62023"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=62023"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=62023"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}