{"id":152097,"date":"2024-11-01T20:05:20","date_gmt":"2024-11-01T12:05:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/152097\/"},"modified":"2024-11-01T20:05:21","modified_gmt":"2024-11-01T12:05:21","slug":"%e9%81%bf%e5%85%8d%e6%95%b8%e6%93%9a%e5%ba%ab%e7%a9%ba%e6%8c%87%e9%87%9d%e7%95%b0%e5%b8%b8%e7%9a%84%e6%96%b9%e6%b3%95-%e6%95%b8%e6%93%9a%e5%ba%ab%e7%a9%ba%e6%8c%87%e9%87%9d%e7%95%b0%e5%b8%b8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/152097\/","title":{"rendered":"\u907f\u514d\u6578\u64da\u5eab\u7a7a\u6307\u91dd\u7570\u5e38\u7684\u65b9\u6cd5 (\u6578\u64da\u5eab\u7a7a\u6307\u91dd\u7570\u5e38)"},"content":{"rendered":"<h1 id=\"%e9%81%bf%e5%85%8d%e6%95%b8%e6%93%9a%e5%ba%ab%e7%a9%ba%e6%8c%87%e9%87%9d%e7%95%b0%e5%b8%b8%e7%9a%84%e6%96%b9%e6%b3%95-%e6%95%b8%e6%93%9a%e5%ba%ab%e7%a9%ba%e6%8c%87%e9%87%9d%e7%95%b0%e5%b8%b8-HEtUtyeDqe\">\u907f\u514d\u6578\u64da\u5eab\u7a7a\u6307\u91dd\u7570\u5e38\u7684\u65b9\u6cd5 (\u6578\u64da\u5eab\u7a7a\u6307\u91dd\u7570\u5e38)<\/h1>\n<p>\u5728\u73fe\u4ee3\u7684\u61c9\u7528\u7a0b\u5f0f\u958b\u767c\u4e2d\uff0c\u6578\u64da\u5eab\u7684\u4f7f\u7528\u5df2\u7d93\u6210\u70ba\u4e0d\u53ef\u6216\u7f3a\u7684\u4e00\u90e8\u5206\u3002\u7136\u800c\uff0c\u958b\u767c\u8005\u5728\u8207\u6578\u64da\u5eab\u4ea4\u4e92\u6642\uff0c\u7d93\u5e38\u6703\u9047\u5230\u4e00\u500b\u5e38\u898b\u7684\u554f\u984c\u2014\u2014\u7a7a\u6307\u91dd\u7570\u5e38\uff08Null Pointer Exception\uff09\u3002\u9019\u7a2e\u7570\u5e38\u901a\u5e38\u767c\u751f\u5728\u5617\u8a66\u8a2a\u554f\u4e00\u500b\u672a\u521d\u59cb\u5316\u6216\u70ba\u7a7a\u7684\u5c0d\u8c61\u6642\uff0c\u5c0d\u65bc\u6578\u64da\u5eab\u64cd\u4f5c\u4f86\u8aaa\uff0c\u9019\u53ef\u80fd\u5c0e\u81f4\u61c9\u7528\u7a0b\u5f0f\u5d29\u6f70\u6216\u6578\u64da\u640d\u58de\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u907f\u514d\u6578\u64da\u5eab\u7a7a\u6307\u91dd\u7570\u5e38\u7684\u5e7e\u7a2e\u6709\u6548\u65b9\u6cd5\u3002<\/p>\n<h2 id=\"1-%e6%aa%a2%e6%9f%a5%e6%95%b8%e6%93%9a%e5%ba%ab%e9%80%a3%e6%8e%a5-HEtUtyeDqe\">1. \u6aa2\u67e5\u6578\u64da\u5eab\u9023\u63a5<\/h2>\n<p>\u5728\u9032\u884c\u4efb\u4f55\u6578\u64da\u5eab\u64cd\u4f5c\u4e4b\u524d\uff0c\u9996\u5148\u8981\u78ba\u4fdd\u6578\u64da\u5eab\u9023\u63a5\u662f\u6709\u6548\u7684\u3002\u958b\u767c\u8005\u61c9\u8a72\u5728\u57f7\u884c\u67e5\u8a62\u4e4b\u524d\u6aa2\u67e5\u9023\u63a5\u5c0d\u8c61\u662f\u5426\u70ba\u7a7a\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>if (connection != null) {\n    \/\/ \u57f7\u884c\u6578\u64da\u5eab\u64cd\u4f5c\n} else {\n    \/\/ \u8655\u7406\u9023\u63a5\u5931\u6557\u7684\u60c5\u6cc1\n}<\/code><\/pre>\n<h2 id=\"2-%e4%bd%bf%e7%94%a8%e9%a0%90%e5%82%99%e8%aa%9e%e5%8f%a5-HEtUtyeDqe\">2. \u4f7f\u7528\u9810\u5099\u8a9e\u53e5<\/h2>\n<p>\u4f7f\u7528\u9810\u5099\u8a9e\u53e5\uff08Prepared Statements\uff09\u4e0d\u50c5\u53ef\u4ee5\u63d0\u9ad8\u6027\u80fd\uff0c\u9084\u80fd\u6709\u6548\u9632\u6b62\u7a7a\u6307\u91dd\u7570\u5e38\u3002\u9810\u5099\u8a9e\u53e5\u80fd\u5920\u81ea\u52d5\u8655\u7406\u7a7a\u503c\uff0c\u4e26\u4e14\u5728\u57f7\u884c\u67e5\u8a62\u6642\u6703\u9032\u884c\u5fc5\u8981\u7684\u6aa2\u67e5\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528\u9810\u5099\u8a9e\u53e5\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>String sql = \"SELECT * FROM users WHERE id = ?\";\nPreparedStatement pstmt = connection.prepareStatement(sql);\npstmt.setInt(1, userId);\nResultSet rs = pstmt.executeQuery();<\/code><\/pre>\n<h2 id=\"3-%e8%99%95%e7%90%86%e6%9f%a5%e8%a9%a2%e7%b5%90%e6%9e%9c-HEtUtyeDqe\">3. \u8655\u7406\u67e5\u8a62\u7d50\u679c<\/h2>\n<p>\u5728\u57f7\u884c\u67e5\u8a62\u5f8c\uff0c\u958b\u767c\u8005\u61c9\u8a72\u6aa2\u67e5\u7d50\u679c\u96c6\uff08ResultSet\uff09\u662f\u5426\u70ba\u7a7a\u3002\u9019\u53ef\u4ee5\u901a\u904e\u8abf\u7528 <code>next()<\/code> \u65b9\u6cd5\u4f86\u5be6\u73fe\uff0c\u8a72\u65b9\u6cd5\u6703\u8fd4\u56de\u4e00\u500b\u5e03\u6797\u503c\uff0c\u6307\u793a\u662f\u5426\u6709\u6578\u64da\u53ef\u4f9b\u8a2a\u554f\uff1a<\/p>\n<pre><code>if (rs.next()) {\n    \/\/ \u8655\u7406\u7d50\u679c\n} else {\n    \/\/ \u8655\u7406\u6c92\u6709\u7d50\u679c\u7684\u60c5\u6cc1\n}<\/code><\/pre>\n<h2 id=\"4-%e4%bd%bf%e7%94%a8%e9%81%a9%e7%95%b6%e7%9a%84%e9%8c%af%e8%aa%a4%e8%99%95%e7%90%86%e6%a9%9f%e5%88%b6-HEtUtyeDqe\">4. \u4f7f\u7528\u9069\u7576\u7684\u932f\u8aa4\u8655\u7406\u6a5f\u5236<\/h2>\n<p>\u5728\u6578\u64da\u5eab\u64cd\u4f5c\u4e2d\uff0c\u932f\u8aa4\u8655\u7406\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u958b\u767c\u8005\u61c9\u8a72\u4f7f\u7528 <code>try-catch<\/code> \u584a\u4f86\u6355\u7372\u53ef\u80fd\u767c\u751f\u7684\u7570\u5e38\uff0c\u4e26\u9032\u884c\u9069\u7576\u7684\u8655\u7406\u3002\u9019\u6a23\u53ef\u4ee5\u9632\u6b62\u61c9\u7528\u7a0b\u5f0f\u56e0\u70ba\u672a\u8655\u7406\u7684\u7570\u5e38\u800c\u5d29\u6f70\uff1a<\/p>\n<pre><code>try {\n    \/\/ \u6578\u64da\u5eab\u64cd\u4f5c\n} catch (SQLException e) {\n    \/\/ \u8655\u7406SQL\u7570\u5e38\n} catch (NullPointerException e) {\n    \/\/ \u8655\u7406\u7a7a\u6307\u91dd\u7570\u5e38\n}<\/code><\/pre>\n<h2 id=\"5-%e4%bd%bf%e7%94%a8-orm-%e6%a1%86%e6%9e%b6-HEtUtyeDqe\">5. \u4f7f\u7528 ORM \u6846\u67b6<\/h2>\n<p>\u5c0d\u65bc\u8a31\u591a\u958b\u767c\u8005\u4f86\u8aaa\uff0c\u4f7f\u7528\u5c0d\u8c61\u95dc\u4fc2\u6620\u5c04\uff08ORM\uff09\u6846\u67b6\u53ef\u4ee5\u5927\u5927\u7c21\u5316\u6578\u64da\u5eab\u64cd\u4f5c\u3002ORM \u6846\u67b6\u5982 Hibernate \u6216 Entity Framework \u80fd\u5920\u81ea\u52d5\u8655\u7406\u8a31\u591a\u5e95\u5c64\u7684\u6578\u64da\u5eab\u4ea4\u4e92\uff0c\u4e26\u4e14\u901a\u5e38\u6703\u5167\u5efa\u7a7a\u503c\u6aa2\u67e5\u6a5f\u5236\uff0c\u5f9e\u800c\u6e1b\u5c11\u7a7a\u6307\u91dd\u7570\u5e38\u7684\u98a8\u96aa\u3002<\/p>\n<h2 id=\"6-%e5%96%84%e7%94%a8%e6%97%a5%e8%aa%8c%e8%a8%98%e9%8c%84-HEtUtyeDqe\">6. \u5584\u7528\u65e5\u8a8c\u8a18\u9304<\/h2>\n<p>\u5728\u958b\u767c\u904e\u7a0b\u4e2d\uff0c\u826f\u597d\u7684\u65e5\u8a8c\u8a18\u9304\u7fd2\u6163\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u5feb\u901f\u5b9a\u4f4d\u554f\u984c\u3002\u7576\u767c\u751f\u7a7a\u6307\u91dd\u7570\u5e38\u6642\uff0c\u8a18\u9304\u8a73\u7d30\u7684\u932f\u8aa4\u4fe1\u606f\u548c\u4e0a\u4e0b\u6587\uff0c\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u66f4\u5feb\u5730\u627e\u5230\u554f\u984c\u6240\u5728\uff0c\u4e26\u9032\u884c\u4fee\u5fa9\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-HEtUtyeDqe\">\u7e3d\u7d50<\/h2>\n<p>\u907f\u514d\u6578\u64da\u5eab\u7a7a\u6307\u91dd\u7570\u5e38\u662f\u78ba\u4fdd\u61c9\u7528\u7a0b\u5f0f\u7a69\u5b9a\u6027\u548c\u53ef\u9760\u6027\u7684\u95dc\u9375\u3002\u901a\u904e\u6aa2\u67e5\u6578\u64da\u5eab\u9023\u63a5\u3001\u4f7f\u7528\u9810\u5099\u8a9e\u53e5\u3001\u8655\u7406\u67e5\u8a62\u7d50\u679c\u3001\u5be6\u65bd\u932f\u8aa4\u8655\u7406\u3001\u5229\u7528 ORM \u6846\u67b6\u4ee5\u53ca\u826f\u597d\u7684\u65e5\u8a8c\u8a18\u9304\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u6709\u6548\u5730\u6e1b\u5c11\u9019\u985e\u7570\u5e38\u7684\u767c\u751f\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u80fd\u548c\u7a69\u5b9a\u6027\u7684\u61c9\u7528\u7a0b\u5f0f\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u6216 <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u4f86\u90e8\u7f72\u6578\u64da\u5eab\u4e5f\u662f\u4e00\u500b\u91cd\u8981\u7684\u8003\u91cf\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3\u907f\u514d\u6578\u64da\u5eab\u7a7a\u6307\u91dd\u7570\u5e38\u7684\u65b9\u6cd5\uff0c\u78ba\u4fdd\u6578\u64da\u5b8c\u6574\u6027\u8207\u61c9\u7528\u7a69\u5b9a\u6027\uff0c\u63d0\u5347\u7cfb\u7d71\u6548\u80fd\u8207\u7528\u6236\u9ad4\u9a57\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-152097","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/152097","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=152097"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/152097\/revisions"}],"predecessor-version":[{"id":152098,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/152097\/revisions\/152098"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=152097"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=152097"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=152097"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}