Xerophytes live under conditions of drought/desert. All adaptations toward obtaining little available water and conserving such. Deep rooted species are common, storage organs are common, reduced transpiration, there are also adaptations which ensure survival of offspring in adverse conditions, e.g seed dormancy
Halophytes live under conditions of high salt content of soil or water. Osmotic pressure of soil is higher than that of ordinary plants roots, breathing root/pneumatophores. Halophytes plant root exert greater osmotic pressure than that of ordinary plants. They also possess water storage tissue which hells to overcome period of physiological drought.