  We consider the Cauchy problem for one-dimensional (1D) barotropic
compressible Navier-Stokes equations with density-dependent viscosity and large
external force. Under a general assumption on the density-dependent viscosity,
we prove that the Cauchy problem admits a unique global strong (classical)
solution for the large initial data with vacuum. Moreover, the density is
proved to be bounded from above time-independently. As a consequence, we obtain
the large time behavior of the solution without external forces.
