Addressed issues when starting Tomcat with Spring application

Addressed issues when starting Tomcat with Spring application

Issue 1: failed to register JDBC
Problem: registered the jdbc, failed to register com.microsoft.sqlserver.jdbc.SQLServerDriver, prevent memory leak
Solution: overwrite org.apache.commons.dbcp.BasicDataSource

Issue 2: servlet-api offends
Problem: servlet-api offends with tomcat.
Solution: delete servlet-api-2.5.jar

Issue 3
Problem: Could not find value for key log4j.appender.errorlog
Solution: clear the redundant information of log4j.properties

Issue 4
Problem: log4j:WARN No appenders could be found for logger (org.springframework.web.context.ContextLoader).
Solution: append log4j config of spring into log4j.properties

Issue 5: Can not connect to SQL Server
Problem: Can not connect to SQL Server
Solution: modify TCP/IP option of SQL Server Network configuration