Draw line in google map follow the route

I would like a same solution like here:

Sample

but I didn't find a solution nowhere. The 开发者_运维知识库big problem is the follow the route, so I can draw line beetween 2 points, but it's not good. What is the solution? Thanks.

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Use the Directions API. You can find more information on how to make Directions request in Maps in the documentation.

Here is one tutorial on using the API.