Multiple annotations found at this line:

- ArtifactTransferException: Failure to transfer com.fasterxml.jackson.core:jackson-databind:jar:2.9.0.pr3 from http://
repo1.maven.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of
central has elapsed or updates are forced. Original error: Could not transfer artifact com.fasterxml.jackson.core:jackson-
databind:jar:2.9.0.pr3 from/to central (http://repo1.maven.org/maven2): No response received after 60000
- Missing artifact com.fasterxml.jackson.core:jackson-databind:jar:2.9.0.pr3

其实已经说的很清楚了。

因为 那个 2.9.pr3.jar 已经缓存在了本地，  所以下载（transfer ）失败。 只有过了指定的时间间隔， 或 强制更新， 才会去重新 解析。

—— resolution will not be reattempted until the update interval of 
central has elapsed or updates are forced

那么， 把 jackson-databind-2.9.0.pr3.jar.lastUpdated 删除后， maven 就会去重新下载。

修改 pom， （增加了一空行）， 还是不行。。。

Multiple annotations found at this line:
- Missing artifact com.fasterxml.jackson.core:jackson-databind:jar:2.9.0.pr3
- ArtifactTransferException: Could not transfer artifact com.fasterxml.jackson.core:jackson-databind:jar:2.9.0.pr3 
from/to central (http://repo1.maven.org/maven2): No response received after 60000

手动将jackson-databind-2.9.0.pr3.jar 下载到本地， 放到 mvn 仓库中，  再次修改 pom， ok了！

maven 下载jar失败： resolution will not be reattempted until the update interval of central has elapsed or updates are forced