Driver:com.mysql.jdbc.Driver@2b7374f8 为 URL 返回 null答案

【问题标题】：Driver:com.mysql.jdbc.Driver@2b7374f8 returned null for URLDriver:com.mysql.jdbc.Driver@2b7374f8 为 URL 返回 null
【发布时间】：2017-12-13 06:07:27
【问题描述】：

我是 JAVA 的初学者。我正在尝试将远程 mySQL 数据库连接到我的 Java 代码。

我收到以下错误：

    2017-07-09 17:29:04.283 ERROR 38768 --- [lication.main()] org.hibernate.tool.hbm2ddl.SchemaUpdate  : HHH000319: Could not get database metadata

java.sql.SQLException: Driver:com.mysql.jdbc.Driver@2b7374f8 returned null for URL:jdbc:mysql:sg2plcpnl9557.produc.sin1.secure.net:3312/abc
    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:326)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:200)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:699)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:126)
    at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:139)
    at org.hibernate.tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.prepare(SuppliedConnectionProviderConnectionHelper.java:51)
    at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:219)
    at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:203)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:522)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1859)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:857)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:850)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:425)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:849)
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60)
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:343)
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1633)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:956)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:747)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:686)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:320)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:957)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:946)
    at com.home.Application.main(Application.java:10)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.springframework.boot.maven.RunMojo$LaunchRunner.run(RunMojo.java:418)
    at java.lang.Thread.run(Thread.java:745)

2017-07-09 17:29:04.284 ERROR 38768 --- [lication.main()] org.hibernate.tool.hbm2ddl.SchemaUpdate  : HHH000299: Could not complete schema update

java.sql.SQLException: Driver:com.mysql.jdbc.Driver@2b7374f8 returned null for URL:jdbc:mysql:sg2plcpnl9557.produc.sin1.secure.net:3312/abc
    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:326)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:200)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:699)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:126)
    at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:139)
    at org.hibernate.tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.prepare(SuppliedConnectionProviderConnectionHelper.java:51)
    at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:219)
    at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:203)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:522)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1859)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:857)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:850)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:425)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:849)
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60)
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:343)
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1633)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:956)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:747)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:686)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:320)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:957)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:946)
    at com.home.Application.main(Application.java:10)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.springframework.boot.maven.RunMojo$LaunchRunner.run(RunMojo.java:418)
    at java.lang.Thread.run(Thread.java:745)

这是我的属性文件：

    server.port=8090
#Basic Spring Boot Config for Oracle
spring.datasource.url= jdbc:mysql:sg2plcpnl9557.produc.sin1.secure.net:3312/abc
spring.datasource.username=abc
spring.datasource.password=12345
spring.datasource.driverClassName=com.mysql.jdbc.Driver
#spring.datasource.driver-class-name=oracle.jdbc.OracleDriver
#spring.datasource.driver-class-name=com.mysql.jdbc.Driver

#hibernate config
#spring.jpa.database-platform=org.hibernate.dialect.Oracle10gDialect
spring.jpa.database-platform=org.hibernate.dialect.MySQLDialect
spring.jpa.show-sql=true 
spring.jpa.hibernate.ddl-auto=update

我在 pom.xml 中的依赖是：

<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
</dependency>

【问题讨论】：

标签： java mysql maven jdbc spring-boot

【解决方案1】：

您的 JDBC url 不是 MySQL 连接器/J 驱动程序识别的格式，因此通过返回 null 来拒绝它，如java.sql.Driver.connect 中所述：

尝试与给定 URL 建立数据库连接。司机如果它意识到它是错误类型的驱动程序，则应返回“null” 连接到给定的 URL。这很常见，就像 JDBC 驱动程序一样 manager 被要求连接到给定的 URL，它将 URL 传递给每个依次加载驱动程序。

如MySQL Connector/J documentation 中所述，MySQL 连接器/J 驱动程序的 URL 格式为：

jdbc:mysql://[host1][:port1][,[host2][:port2]]...[/[database]] »
[?propertyName1=propertyValue1[&propertyName2=propertyValue2]...]

您的网址至少应为：

jdbc:mysql://sg2plcpnl9557.produc.sin1.secure.net:3312/abc

【讨论】：

谢谢马克！！这对我有用。但现在问题是这个数据库在 godaddy.com 上，为了访问这个数据库，我总是必须允许我的 IP 地址。有什么方法可以让我在不授予特定权限的情况下连接到我的数据库
@Girjesh 那是你需要问godaddy的事情。一般来说，不允许互联网上的任何随机 IP 地址连接到数据库是一种很好的安全措施。因此，需要将您的 IP 地址列入白名单是正常的（从安全角度来看：必需）。不过，也许 godaddy 有其他选择。

【解决方案2】：

您的数据源 URL 错误。应该是这样的：

spring.datasource.url=jdbc:mysql://sg2plcpnl9557.produc.sin1.secure.net:3312/abc

您可以阅读有关“使用 MySQL 访问数据”here 的更多信息。

【讨论】：

【解决方案3】：

先修复你的连接：

正确的是：

spring.datasource.url=jdbc:mysql://sg2plcpnl9557.produc.sin1.secure.net:3312/abc

【讨论】：

【解决方案4】：

对于遇到此问题的开发人员来说，还有一件非常重要的事情要注意。请确保您的数据库名称没有任何特殊字符。避免使用诸如“abc-xyz”之类的名称。如果有人使用这样的名称并获得空指针，则将其替换为“abc_xyz”。您将节省大量时间和精力。

【讨论】：

【解决方案5】：

在我的例子中，旧网址是：URL:jdbc:wm:sqlserver://uABC1.database.windows.net:1433;databaseName=xyz01-wm14532ds

我从 jdbc:wm:sqlserver 中删除了 WM，连接测试成功。

【讨论】：