{"id":85803,"date":"2020-05-11T20:26:26","date_gmt":"2020-05-11T12:26:26","guid":{"rendered":"http:\/\/4563.org\/?p=85803"},"modified":"2020-05-11T20:26:26","modified_gmt":"2020-05-11T12:26:26","slug":"java-%e5%85%b3%e4%ba%8e-class-fornamecom-mysql-jdbc-driver-%e6%9c%aa%e9%81%b5%e5%ae%88%e4%ba%86%e5%8f%8c%e4%ba%b2%e5%a7%94%e6%b4%be%e6%a8%a1%e5%9e%8b%e8%bf%99%e4%bb%b6%e4%ba%8b%e6%9c%89%e4%bb%80","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=85803","title":{"rendered":"Java \u5173\u4e8e Class.forName(com.mysql.jdbc.Driver) \u672a\u9075\u5b88\u4e86\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\u8fd9\u4ef6\u4e8b\u6709\u4ec0\u4e48\u6bd4\u8f83\u597d\u8d44\u6599\u4e48?"},"content":{"rendered":"
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Java \u5173\u4e8e Class.forName(com.mysql.jdbc.Driver) \u672a\u9075\u5b88\u4e86\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\u8fd9\u4ef6\u4e8b\u6709\u4ec0\u4e48\u6bd4\u8f83\u597d\u8d44\u6599\u4e48? <\/h1>\n

<\/p>\n

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\u8cc7\u6df1\u5927\u4f6c : Newyorkcity <\/span> <\/i> 4<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
\u4e3a\u4ec0\u4e48\u5fc5\u987b\u8981\u7834\u574f\uff1f<\/p>\n

\u5982\u4f55\u7834\u574f\u7684\uff1f<\/p>\n

\u8c22\u8c22 <\/p><\/div>\n

\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (2<\/span>) <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n
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  • \n
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    \u8cc7\u6df1\u5927\u4f6c : sawyera <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u5148\u8bf4\u7ed3\u8bba\uff1aClass.forName \u9075\u5faa\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236<\/p>\n

    \u53c2\u8003\uff1a
    Class.forName \u65b9\u6cd5\uff1a
    @CallerSensitive
    public static Class<?> forName(String className)
    throws ClassNotFoundException {
    Class<?> caller = Reflection.getCallerClass();
    return forName0(className, true, ClassLoader.getClassLoader(caller), caller);
    }<\/p>\n

    \u53ef\u4ee5\u770b\u51fa\u662f\u4f7f\u7528 ClassLoader.getClassLoader(caller) \u7c7b\u52a0\u8f7d\u5668\u8fdb\u884c\u52a0\u8f7d\u7684\uff0c\u9ed8\u8ba4\u662f\u4f7f\u7528\u7684\u7528\u6237\u7c7b\u52a0\u8f7d\u5668\uff0c\u8fd8\u662f\u7b26\u5408\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\u7684\u3002<\/p>\n

    \u5982\u6709\u9519\u8bef\uff0c\u8bf7\u6307\u51fa <\/p><\/div>\n<\/p><\/div>\n<\/li>\n

  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : isir1234 <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u4e3a\u4ec0\u4e48\u5fc5\u987b\u8981\u7834\u574f?::
    DriverManager::getConnection \u65b9\u6cd5\u9700\u8981\u6839\u636e\u53c2\u6570\u4f20\u8fdb\u6765\u7684 url \u4ece\u6240\u6709\u5df2\u7ecf\u52a0\u8f7d\u8fc7\u7684 Drivers \u91cc\u627e\u5230\u4e00\u4e2a\u5408\u9002\u7684 Driver \u5b9e\u73b0\u7c7b\u53bb\u8fde\u63a5\u6570\u636e\u5e93.
    Driver \u5b9e\u73b0\u7c7b\u5728\u7b2c\u4e09\u65b9 jar \u91cc, \u8981\u7528 AppClassLoader \u52a0\u8f7d. \u800c DriverManager \u662f rt.jar \u91cc\u7684\u7c7b, \u88ab BootstrapClassLoader \u52a0\u8f7d, DriverManager \u6ca1\u6cd5\u7528 BootstrapClassLoader \u53bb\u52a0\u8f7d Driver \u5b9e\u73b0\u7c7b, \u6240\u4ee5\u53ea\u80fd\u7834\u574f\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b, \u7528\u5b83\u4e0b\u7ea7\u7684 AppClassLoader \u53bb\u52a0\u8f7d Driver.<\/p>\n

    \u5982\u4f55\u7834\u574f\u7684?::
    > SPI \u673a\u5236
    Driver \u5177\u4f53\u7684\u5b9e\u73b0\u7c7b jar \u5305\u5728 META-INF\/services\/java.sql.Driver \u6587\u4ef6\u91cc\u5199\u4e0a\u81ea\u5df1 Driver \u5b9e\u73b0\u7c7b\u7684\u5168\u9650\u5b9a\u540d, \u6bd4\u5982 `org.postgresql.Driver` , JDK8 \u7684 DriverManager \u5728 static \u4ee3\u7801\u5757\u91cc(JDK14 \u662f\u5728\u7b2c\u4e00\u6b21 getConnection \u65f6)\u4f1a\u7528 ServiceLoader \u83b7\u53d6\u6240\u6709\u7684 Driver \u5e76\u4f7f\u7528 Thread.currentThread().getContextClassLoader() \u83b7\u53d6\u5230\u7684 AppClassLoader \u52a0\u8f7d\u8be5\u7c7b, Driver \u5b9e\u73b0\u7c7b\u7684 static \u4ee3\u7801\u5757\u4f1a\u53bb\u8c03\u7528 DriverManager::registerDriver \u5c06\u81ea\u5df1\u6ce8\u518c\u5230 DriverManager \u91cc.<\/p>\n

    \u4e2a\u4eba\u7406\u89e3… <\/p><\/div>\n<\/p><\/div>\n<\/li>\n

  • \n","protected":false},"excerpt":{"rendered":"

    Java \u5173\u4e8e Class.for…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/85803"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=85803"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/85803\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=85803"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=85803"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=85803"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}