java - mysql主从复制问题: Cannot create PoolableConnectionFactory

Question

我花了很多时间还是想不通。我知道，如果我使用 BasicDataSource，则需要在 openjpa.ConnectionProperties 属性中传递配置。 openjpa.ConnectionProperties 是逗号 (,) 分隔的属性，它映射到 DataSource实例。现在MySQL还需要逗号 (,) 分隔格式的主机。所以无法弄清楚，如何使用 MySQL 复制创建 DataSource？*

我正在尝试使用 openjpa 设置主/从数据库，但在从 EntityManagerFactory 创建 createEntityManager() 时失败并出现以下异常。

代码如下:

String driver ="com.mysql.jdbc.ReplicationDriver";
String url = "jdbc:mysql:replication://master:3306,slave:3306/db";
String user = "abc";
String password = "123";
String connProps = "DriverClassName={0},Url={1},Username={2},Password={3}";

public void method() {
    connProps = MessageFormat.format(connProps, driver, url, user, password);
    Properties props = new Properties();
    props.setProperty("openjpa.ConnectionProperties", connProps);
    props.setProperty("openjpa.ConnectionDriverName", "org.apache.commons.dbcp.BasicDataSource");
    EntityManagerFactory factory = Persistence.createEntityManagerFactory("mysql", props);
    EntityManager manager = factory.createEntityManager();
}

我收到以下异常:

Exception in thread "main" <openjpa-2.4.1-r422266:1730418 fatal general error> org.apache.openjpa.persistence.PersistenceException: Cannot create PoolableConnectionFactory (Must specify at least one slave host to connect to for master/slave replication load-balancing functionality)
    at org.apache.openjpa.jdbc.sql.DBDictionaryFactory.newDBDictionary(DBDictionaryFactory.java:106)
    at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.getDBDictionaryInstance(JDBCConfigurationImpl.java:603)
    at org.apache.openjpa.jdbc.meta.MappingRepository.endConfiguration(MappingRepository.java:1520)
    at org.apache.openjpa.lib.conf.Configurations.configureInstance(Configurations.java:533)
    at org.apache.openjpa.lib.conf.Configurations.configureInstance(Configurations.java:458)
    at org.apache.openjpa.lib.conf.PluginValue.instantiate(PluginValue.java:121)
    at org.apache.openjpa.conf.MetaDataRepositoryValue.instantiate(MetaDataRepositoryValue.java:68)
    at org.apache.openjpa.lib.conf.ObjectValue.instantiate(ObjectValue.java:83)
    at org.apache.openjpa.conf.OpenJPAConfigurationImpl.newMetaDataRepositoryInstance(OpenJPAConfigurationImpl.java:967)
    at org.apache.openjpa.conf.OpenJPAConfigurationImpl.getMetaDataRepositoryInstance(OpenJPAConfigurationImpl.java:958)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:642)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:202)
    at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:154)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:226)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:153)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:59)
    at ExampleJPA.method(ExampleJPA.java:22)
    at ExampleJPA.main(ExampleJPA.java:27)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Must specify at least one slave host to connect to for master/slave replication load-balancing functionality)
    at org.apache.commons.dbcp.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:1549)
    at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1388)
    at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
    at org.apache.openjpa.lib.jdbc.DelegatingDataSource.getConnection(DelegatingDataSource.java:110)
    at org.apache.openjpa.lib.jdbc.DecoratingDataSource.getConnection(DecoratingDataSource.java:86)
    at org.apache.openjpa.jdbc.sql.DBDictionaryFactory.newDBDictionary(DBDictionaryFactory.java:90)
    ... 22 more
Caused by: java.sql.SQLException: Must specify at least one slave host to connect to for master/slave replication load-balancing functionality
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:957)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:896)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:885)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
    at com.mysql.jdbc.NonRegisteringDriver.connectReplicationConnection(NonRegisteringDriver.java:414)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:313)
    at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
    at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:582)
    at org.apache.commons.dbcp.BasicDataSource.validateConnectionFactory(BasicDataSource.java:1556)
    at org.apache.commons.dbcp.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:1545)
    ... 27 more

数据库的主从设置似乎工作正常。我已经通过 telnet 检查了主从的连接。

Answer 1

在花了这么多时间之后，这个解决方案看起来很愚蠢。我得到了这个工作。我需要用双引号传递 jdbc url ("jdbc:mysql:replication://master:3306,slave:3306/db") 然后工作正常。

我会尽快提供更多信息。