Dependency injection through constructors or property setters?

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I'm refactoring a class and adding a new dependency to it. The class is currently taking its existing dependencies in the constructor. So for consistency, I add the parameter to the constructor.
Of course, there are a few subclasses plus even more for unit tests, so now I am playing the game of going around altering all the constructors to match, and it's taking ages.
It makes me think that using properties with setters is a better way of getting dependencies. I don't think injected dependencies should be part of the interface to constructing an instance of a class. You add a dependency and now all your users (subclasses and anyone instantiating you directly) suddenly know about it. That feels like a break of encapsulation.

This doesn't seem to be the pattern with the existing code here, so I am looking to find out what the general consensus is, pros and cons of constructors versus properties. Is using property setters better?

dependency-injection inversion-of-control
15 Answers

When to use Constructor injection?
When we want to make sure that the Object is created with all of its dependencies and to ensure that required dependencies are not null.

When to use Setter injection?
When we are working with optional dependencies that can be assigned reasonable default values within the class. Otherwise, not-null checks must be performed everywhere the code uses the dependency. Additionally, setter methods make objects of that class open to reconfiguration or re-injection at a later time.

Sources: Spring documentation , Java Revisited

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