【发布时间】：2017-05-26 14:36:39
【问题描述】：
我已经在 Spring 配置中定义了一个数据源。
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/db" />
<property name="username" value="root" />
<property name="password" value="password" />
</bean>
对于LOG4J2 JDBCAppender，我知道我们需要获取数据源：
<JDBC name="databaseAppender" tableName="error_log">
<ConnectionFactory class="net.example.db"
method="getDatabaseConnection" />
<Column name="EVENT_DATE" isEventTimestamp="true" />
<Column name="LEVEL" pattern="%level" />
<Column name="LOGGER" pattern="%logger" />
<Column name="MESSAGE" pattern="%message" />
<Column name="THROWABLE" pattern="%ex{full}" />
</JDBC>
我已经将包添加到组件扫描中：
<context:component-scan base-package="com.test,net.example.db" />
并在 ConnectionFactory 类中添加注解作为组件
import java.sql.Connection;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class ConnectionFactory {
@Autowired
private DataSource dataSource;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
public Connection getDatabaseConnection() throws Exception {
return dataSource.getConnection();
}
}
但是，当我调用 getDatabaseConnection() 时我得到了 null
2017-01-14 14:17:24,579 localhost-startStop-1 ERROR JdbcDatabaseManager jdbcManager{ description=databaseAppender, bufferSize=0, connectionSource=factory{ public static java.sql.Connection net.example.db.ConnectionFactory.getDatabaseConnection() }, tableName=error_log, columns=[ { name=EVENT_DATE, layout=null, literal=null, timestamp=true }, { name=LEVEL, layout=%level, literal=null, timestamp=false }, { name=LOGGER, layout=%logger, literal=null, timestamp=false }, { name=MESSAGE, layout=%message, literal=null, timestamp=false }, { name=THROWABLE, layout=%ex{full}, literal=null, timestamp=false } ] } Could not perform database startup operations: java.sql.SQLException: Failed to obtain connection from factory method. java.sql.SQLException: Failed to obtain connection from factory method.
at org.apache.logging.log4j.core.appender.db.jdbc.FactoryMethodConnectionSource$1.getConnection(FactoryMethodConnectionSource.java:107)
at org.apache.logging.log4j.core.appender.db.jdbc.FactoryMethodConnectionSource.getConnection(FactoryMethodConnectionSource.java:53)
at org.apache.logging.log4j.core.appender.db.jdbc.JdbcDatabaseManager.startupInternal(JdbcDatabaseManager.java:60)
at org.apache.logging.log4j.core.appender.db.AbstractDatabaseManager.startup(AbstractDatabaseManager.java:65)
at org.apache.logging.log4j.core.appender.db.AbstractDatabaseAppender.start(AbstractDatabaseAppender.java:89)
at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:255)
at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:530)
at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:258)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:239)
at org.apache.logging.log4j.core.config.Configurator.initialize(Configurator.java:158)
at org.apache.logging.log4j.web.Log4jWebInitializerImpl.initializeNonJndi(Log4jWebInitializerImpl.java:168)
at org.apache.logging.log4j.web.Log4jWebInitializerImpl.start(Log4jWebInitializerImpl.java:110)
at org.apache.logging.log4j.web.Log4jServletContainerInitializer.onStartup(Log4jServletContainerInitializer.java:57)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5604)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1571)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1561)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
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.apache.logging.log4j.core.appender.db.jdbc.FactoryMethodConnectionSource$1.getConnection(FactoryMethodConnectionSource.java:105)
... 20 more
我怀疑 LOGJ2 调用 getDatabaseConnection() 时是否还没有创建 bean 数据源。请告诉我是什么原因和解决方案。
【问题讨论】：
-
为什么不呢？是的，您可以提供连接工厂类是组件扫描的一部分，并创建它的 bean。
-
嗨 Barath，请在帖子中查看我的更新。我已经实现了您提到的要点，但是我的 dataSource 为空。
-
ConnectionFactory 的包名是什么。确保它是组件扫描基础包的一部分
-
我已经在组件扫描中添加了包名：包名是net.example.db，如问题中所述。
-
Log4J 没有从 Spring 上下文中获取 ConnectionFactory。所以 Spring 不知道这个对象，也不会在其中注入任何东西。顺便说一句，即使 log4j 使用了 spring 上下文，您的连接工厂也在包
hk.gov.lcsd.mois.logging中，而您只是在扫描包com.test,net.example.db。最后，您错过了文档的一个重要部分：无论您采用哪种方法，都必须有连接池支持。否则，日志记录性能将受到很大影响。