  The deflection and gravitational lensing of light and massive particles in
arbitrary static, spherically symmetric and asymptotically (anti-)de Sitter
spacetimes are considered in this work. We first proved that for spacetimes
whose metric satisfying certain conditions, the deflection of null rays with
fixed closest distance will not depend on the cosmological constant $\Lambda$,
while that of timelike signals and the apparent angle in gravitational lensing
still depend on $\Lambda$. A two-step perturbative method is then developed to
compute the change of the angular coordinate and total travel time in the weak
field limit. The results are quasi-series of two small quantities, with the
finite distance effect of the source/detector naturally taken into account.
These results are verified by applying to some known de Sitter spacetimes.
Using an exact gravitational lensing equation, we solved the apparent angles of
the images and time delays between them and studied the effect of $\Lambda$ on
them. It is found that generally, a small positive $\Lambda$ will decrease the
apparent angle of images from both sides of the lens and increase the time
delay between them. The time delay between signals from the same side of the
lens but with different energy however, will be decreased by $\Lambda$.
