You can use auto-formatting (CTRL + ALT + L), after few changes in Code Style settings.
Press CTRL + ALT + S to open Settings window
Find Code Style / Java section
Make sure to uncheck "Line Breaks" option and check "Ensure right margin is not exceeded" option
Press OK to accept changes you've made
Now when using auto-formatting (CTRL + ALT + L) long strings exceeding line character limit will be automatically cut into multiple lines.