Map to String in Java

问题:

When I do System.out.println(map) in Java, I get a nice output in stdout. How can I obtain this same string representation of a Map in a variable without meddling with standard output? Something like String mapAsString = Collections.toString(map)?

回答1:

Use Object#toString().

String string = map.toString();

That's after all also what System.out.println(object) does under the hoods. The format for maps is described in AbstractMap#toString().

回答2:

You can also use google-collections (guava) Joiner class if you want to customize the print format