tree 9b8e7ce7f967e90d25e6dc72d8c58d6e08a7ff2c
parent 74afe236d31d79bc7a2418e5caa2880362a7cbe1
author zhang.lei <zhang.lei@99cloud.net> 1456800601 +0800
committer zhang.lei <zhang.lei@99cloud.net> 1457580118 +0800

Optimize "open" method with context manager

Use opening context manager to open a file.
Change-Id: Ice9be6350fd01cbf5eec686ac68d7fc8b5a4d5bd