如何修复错误？log4j.properties#Definetherootloggerwithappenderfilelog4j.rootLogger=ALL,DB#DefinetheDBappenderlog4j.appender.DB=org.apache.log4j.jdbc.JDBCAppender#SetJDBCURLlog4j.appender.DB.URL=jdbc:mysql://localhost/youtube#SetDatabaseDriverlog4j.appender.DB.driver=com.mysql.jdbc.Driver#Setdatabaseuse