简单的service成处理CRUD

未解耦：

public class CustomerServiceImpl implements CustomerService {
	private CustomerDao dao = new CustomerDaoMySqlImpl();//练习时要解耦
	public void addCustomer(Customer customer) {
		//设置id
		customer.setId(IdGenerator.genId());
		//存储
		dao.addCustomer(customer);
	}

	public void deleteCustomer(String customerId) {
		try {
			dao.deleteCustomer(customerId);
		} catch (IdIsNullException e) {
			throw new RuntimeException("ID不能为空");
		}
	}

	public List<Customer> findAll() {
		return dao.findAll();
	}

	public Customer findById(String customerId) {
		Customer c = null;
		try {
			c = dao.findById(customerId);
		} catch (IdIsNullException e) {
			throw new RuntimeException("ID不能为空");
		}
		return c;
	}

	public void updateCustomer(Customer customer) {
		try {
			dao.updateCustomer(customer);
		} catch (IdIsNullException e) {
			throw new RuntimeException("ID不能为空");
		}
	}

}