Failure to transfer com.thoughtworks.xstream:xstream:jar:1.3.1 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.
解決辦法：
a. 刪除m2\repository 所有 .lastUpdated為副檔名的檔案
b. 然後在工程上點選右鍵，選擇Maven4MyEclipse，然後選擇Update Project Configuration，等待結果
c. 如果還是有錯誤，請多重複幾次