Barack Obama sits on the following committees:

Member, Senate Committee on Foreign Relations
Chairman, Subcommittee on European Affairs
Member, Subcommittee on African Affairs
Member, Subcommittee on East Asian and Pacific Affairs
Member, Subcommittee on International Development and Foreign Assistance, Economic Affairs and International Environmental Protection
Member, Senate Committee on Health, Education, Labor, and Pensions
Member, Subcommittee on Children and Families
Member, Subcommittee on Employment and Workplace Safety
Member, Senate Committee on Homeland Security and Governmental Affairs
Member, Subcommittee on Ad Hoc Subcommittee on State, Local, and Private Sector Preparedness and Integration
Member, Subcommittee on Investigations
Member, Subcommittee on Federal Financial Management, Government Information, Federal Services, and International Security
Member, Senate Committee on Veterans’ Affairs
Congressional Terms

John McCain sits on the following committees:

Ranking Member, Senate Committee on Armed Services
port
Member, Senate Committee on Commerce, Science, and Transportation
Member, Subcommittee on Aviation Operations, Safety, and Security
Member, Subcommittee on Consumer Affairs, Insurance, and Automotive Safety
Member, Subcommittee on Interstate Commerce, Trade, and Tourism
Member, Subcommittee on Science, Technology, and Innovation
Member, Subcommittee on Surface Transportation and Merchant Marine Infrastructure, Safety and Security
Member, Senate Committee on Indian Affairs

It certainly helps, but the reality is that nothing fully prepares you to be President of the United States.