maven中scope参数说明

官方说明文档地址https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope

There are 6 scopes available:

• compile
  This is the default scope, used if none is
  specified. Compile dependencies are available in all classpaths of a
  project. Furthermore, those dependencies are propagated to dependent
  projects.
• provided
  This is much like compile, but indicates
  you expect the JDK or a container to provide the dependency at runtime.
  For example, when building a web application for the Java Enterprise
  Edition, you would set the dependency on the Servlet API and related
  Java EE APIs to scope provided because the web container
  provides those classes. This scope is only available on the compilation
  and test classpath, and is not transitive.
• runtime
  This scope indicates that the dependency is not
  required for compilation, but is for execution. It is in the runtime and
  test classpaths, but not the compile classpath.
• test
  This scope indicates that the dependency is not
  required for normal use of the application, and is only available for
  the test compilation and execution phases.
• system
  This scope is similar to provided except
  that you have to provide the JAR which contains it explicitly. The
  artifact is always available and is not looked up in a repository.
• import (only available in Maven 2.0.9 or later)
  This scope is only used on a dependency of type pom in the <dependencyManagement> section. It indicates that the specified POM should be replaced with the dependencies in that POM's <dependencyManagement> section. Since they are replaced, dependencies with a scope of import do not actually participate in limiting the transitivity of a dependency.

Each of the scopes (except for import) affects transitive
dependencies in different ways, as is demonstrated in the table below.
If a dependency is set to the scope in the left column, transitive
dependencies of that dependency with the scope across the top row will
result in a dependency in the main project with the scope listed at the
intersection. If no scope is listed, it means the dependency will be
omitted.

	compile	provided	runtime	test
compile	compile(*)	-	runtime	-
provided	provided	-	provided	-
runtime	runtime	-	runtime	-
test	test	-	test	-

(*) Note: it is intended that this should be runtime scope
instead, so that all compile dependencies must be explicitly listed -
however, there is the case where the library you depend on extends a
class from another library, forcing you to have available at compile
time. For this reason, compile time dependencies remain as compile scope
even when they are transitive.

<scope>，它主要管理依赖的部署。

• compile，缺省值，适用于所有阶段，会随着项目一起发布。
• provided，类似compile，期望JDK、容器或使用者会提供这个依赖。如servlet.jar。
• runtime，只在运行时使用，如JDBC驱动，适用运行和测试阶段。
• test，只在测试时使用，用于编译和运行测试代码。不会随项目发布。
• system，类似provided，需要显式提供包含依赖的jar，Maven不会在Repository中查找它。