commons logging的getFactory()方法

getFactory()方法返回一个Factory

首先从系统属性获取factory的实现类名，没有则继续

String factoryClass = getSystemProperty(FACTORY_PROPERTY, null);

public static final String FACTORY_PROPERTY = "org.apache.commons.logging.LogFactory";

 

通过JDK1.3的Service Discovery机制 查找factory的实现类名，没有则继续

final InputStream is = getResourceAsStream(contextClassLoader, SERVICE_ID);

protected static final String SERVICE_ID =
        "META-INF/services/org.apache.commons.logging.LogFactory";

查找配置文件

commons-logging.properties

中的属性

org.apache.commons.logging.LogFactory

来查找factory的实现类名，没有则继续

Properties props = getConfigurationFile(contextClassLoader, FACTORY_PROPERTIES);

public static final String FACTORY_PROPERTIES = "commons-logging.properties";

 

String factoryClass = props.getProperty(FACTORY_PROPERTY);

public static final String FACTORY_PROPERTY = "org.apache.commons.logging.LogFactory";

 

最后如果以上3个都没找到，采用

org.apache.commons.logging.impl.LogFactoryImpl

 

factory = newFactory(FACTORY_DEFAULT, thisClassLoader, contextClassLoader);

public static final String FACTORY_DEFAULT = "org.apache.commons.logging.impl.LogFactoryImpl";