Setting Export Environment:

In SQL developer, Go to Tools-->Preferences-->Expand Database--> Expand Utilities-->Select the Export option (Here you can choose Export Data Format) Set it for ‘insert’-->Select Save As ‘Single File’ to export data into a single file.

Exporting the Database:

Click Tools-->Database Export-->Select the database you want to Export from the connection dropdown-->Click next and select all the object types. Click next-->Review the information in the Summary and click Finish.