Addressed issues when starting Tomcat with Spring application

[b]Addressed issues when starting Tomcat with Spring application [/b]

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

[b]Issue 2: servlet-api offends[/b]
Problem: servlet-api offends with tomcat.
Solution: delete servlet-api-2.5.jar

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

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

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