Try maybe splitting this way
yourString.split("\\s(?=\\{)|(?<=\\})\\s")
It will split on every space that have {
after it, or space that have }
before it.
Demo
for (String s : "hello {world} this is {stack overflow} and this is my string"
.split("\\s(?=\\{)|(?<=\\})\\s"))
System.out.println(s);
output
hello
{world}
this is
{stack overflow}
and this is my string