I need to write a java program

Where the program reads an xml file that has a text similar to the following

it will go through each line and merge x and y coordinates together with a "," in between in a single line.

so for example:

after reading the file as an input the system output will be

XandY= 1781.0,308.0,1788.0,318.0, 1744.0, 327.0, 1240.0,223.0, 1640.0, 408.0, 1281.0, 358.0

XandY= this will be top2 compatment coordinates

XandY= this will be top3 compatment coordinates

Thank you.