当我从最新的github分支克隆flink代码时，执行：mvn clean install-pskiptests它会引发如下错误：

[INFO] 
[INFO] ------------------< org.apache.flink:flink-dist_2.11 >------------------
[INFO] Building flink-dist 1.7-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[WARNING] The POM for org.apache.flink:flink-core:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-java:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-scala_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-runtime_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-runtime-web_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-optimizer_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-clients_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-streaming-java_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-streaming-scala_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-streaming-python_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-scala-shell_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-core:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-jmx:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-mesos_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-container_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-statebackend-rocksdb_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-yarn_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-hadoop-fs:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-mapr-fs:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-shaded-hadoop2-uber:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-examples-batch_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-examples-streaming_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-gelly-examples_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-dropwizard:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-ganglia:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-graphite:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-prometheus:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-statsd:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-datadog:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-metrics-slf4j:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-python_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-cep_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-cep-scala_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-gelly_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-gelly-scala_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-ml_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-table_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-sql-client:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-s3-fs-hadoop:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-s3-fs-presto:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-swift-fs-hadoop:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-queryable-state-runtime_2.11:jar:1.7-SNAPSHOT is missing, no dependency information available
[WARNING] The POM for org.apache.flink:flink-test-utils-junit:jar:1.7-SNAPSHOT is missing, no dependency information available
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.299 s
[INFO] Finished at: 2018-09-18T17:44:49+08:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project flink-dist_2.11: Could not resolve dependencies for project org.apache.flink:flink-dist_2.11:jar:1.7-SNAPSHOT: The following artifacts could not be resolved: org.apache.flink:flink-core:jar:1.7-SNAPSHOT, org.apache.flink:flink-java:jar:1.7-SNAPSHOT, org.apache.flink:flink-scala_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-runtime_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-runtime-web_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-optimizer_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-clients_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-streaming-java_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-streaming-scala_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-streaming-python_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-scala-shell_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-core:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-jmx:jar:1.7-SNAPSHOT, org.apache.flink:flink-mesos_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-container_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-statebackend-rocksdb_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-yarn_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-hadoop-fs:jar:1.7-SNAPSHOT, org.apache.flink:flink-mapr-fs:jar:1.7-SNAPSHOT, org.apache.flink:flink-shaded-hadoop2-uber:jar:1.7-SNAPSHOT, org.apache.flink:flink-examples-batch_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-examples-streaming_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-gelly-examples_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-dropwizard:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-ganglia:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-graphite:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-prometheus:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-statsd:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-datadog:jar:1.7-SNAPSHOT, org.apache.flink:flink-metrics-slf4j:jar:1.7-SNAPSHOT, org.apache.flink:flink-python_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-cep_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-cep-scala_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-gelly_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-gelly-scala_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-ml_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-table_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-sql-client:jar:1.7-SNAPSHOT, org.apache.flink:flink-s3-fs-hadoop:jar:1.7-SNAPSHOT, org.apache.flink:flink-s3-fs-presto:jar:1.7-SNAPSHOT, org.apache.flink:flink-swift-fs-hadoop:jar:1.7-SNAPSHOT, org.apache.flink:flink-queryable-state-runtime_2.11:jar:1.7-SNAPSHOT, org.apache.flink:flink-test-utils-junit:jar:1.7-SNAPSHOT: Could not find artifact org.apache.flink:flink-core:jar:1.7-SNAPSHOT -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException

似乎maven下载快照依赖失败了，有人能告诉我怎么解决这个问题吗？我的java版本是1.8.0144，maven版本是3.5.3，内置于Ubuntu14.04。