mvn -U clean compile 和 mvn clean compile 的区别答案

【问题标题】：Difference between mvn -U clean compile and mvn clean compilemvn -U clean compile 和 mvn clean compile 的区别
【发布时间】：2015-11-16 07:39:55
【问题描述】：

我使用这两个命令来解决项目中的依赖问题。 mvn -U clean compile 已解决问题。但我不知道它们之间的区别。请解释这些命令之间的区别以及我何时使用mvn clean compile 和mvn -U clean compile。

【问题讨论】：

标签： maven

【解决方案1】：

-U, --update-snapshots 强制检查远程存储库上的更新版本和快照

see here（6.1.11.下载和验证依赖）：

-clean 将清理（删除所有已编译和复制的资源）您的 maven 项目目标目录。

-install 将执行几乎完整的 Maven 生命周期，例如测试、编译和将新构建复制到本地存储库。

-U 你会告诉 maven 更新本地存储库的远程依赖项（通常是第三方依赖项）以及

【讨论】：

【解决方案2】：

-U,--update-snapshots                  Forces a check for updated
                                       releases and snapshots on remote
                                       repositories

为了您的信息，如果您在命令提示符下执行 mvn -h 命令，那么它将显示所有选项，如下所示。因此，如果您需要了解任何选项的详细信息，可以使用 mvn -h 命令。

usage: mvn [options] [<goal(s)>] [<phase(s)>]
Options:
 -am,--also-make                        If project list is specified, also
                                        build projects required by the
                                        list
 -amd,--also-make-dependents            If project list is specified, also
                                        build projects that depend on
                                        projects on the list
 -B,--batch-mode                        Run in non-interactive (batch)
                                        mode
 -C,--strict-checksums                  Fail the build if checksums don't
                                        match
 -c,--lax-checksums                     Warn if checksums don't match
 -cpu,--check-plugin-updates            Ineffective, only kept for
                                        backward compatibility
 -D,--define <arg>                      Define a system property
 -e,--errors                            Produce execution error messages
 -emp,--encrypt-master-password <arg>   Encrypt master security password
 -ep,--encrypt-password <arg>           Encrypt server password
 -f,--file <arg>                        Force the use of an alternate POM
                                        file (or directory with pom.xml).
 -fae,--fail-at-end                     Only fail the build afterwards;
                                        allow all non-impacted builds to
                                        continue
 -ff,--fail-fast                        Stop at first failure in
                                        reactorized builds
 -fn,--fail-never                       NEVER fail the build, regardless
                                        of project result
 -gs,--global-settings <arg>            Alternate path for the global
                                        settings file
 -h,--help                              Display help information
 -l,--log-file <arg>                    Log file to where all build output
                                        will go.
 -llr,--legacy-local-repository         Use Maven 2 Legacy Local
                                        Repository behaviour, ie no use of
                                        _maven.repositories. Can also be
                                        activated by using
                                        -Dmaven.legacyLocalRepo=true
 -N,--non-recursive                     Do not recurse into sub-projects
 -npr,--no-plugin-registry              Ineffective, only kept for
                                        backward compatibility
 -npu,--no-plugin-updates               Ineffective, only kept for
                                        backward compatibility
 -nsu,--no-snapshot-updates             Suppress SNAPSHOT updates
 -o,--offline                           Work offline
 -P,--activate-profiles <arg>           Comma-delimited list of profiles
                                        to activate
 -pl,--projects <arg>                   Comma-delimited list of specified
                                        reactor projects to build instead
                                        of all projects. A project can be
                                        specified by [groupId]:artifactId
                                        or by its relative path.
 -q,--quiet                             Quiet output - only show errors
 -rf,--resume-from <arg>                Resume reactor from specified
                                        project
 -s,--settings <arg>                    Alternate path for the user
                                        settings file
 -T,--threads <arg>                     Thread count, for instance 2.0C
                                        where C is core multiplied
 -t,--toolchains <arg>                  Alternate path for the user
                                        toolchains file
 -U,--update-snapshots                  Forces a check for updated
                                        releases and snapshots on remote
                                        repositories
 -up,--update-plugins                   Ineffective, only kept for
                                        backward compatibility
 -V,--show-version                      Display version information
                                        WITHOUT stopping build
 -v,--version                           Display version information
 -X,--debug                             Produce execution debug output

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