build.gradle里dependencies標簽頁的實現原理是什么

本篇內容主要講解“build.gradle里dependencies標簽頁的實現原理是什么”，感興趣的朋友不妨來看看。本文介紹的方法操作簡單快捷，實用性強。下面就讓小編來帶大家學習“build.gradle里dependencies標簽頁的實現原理是什么”吧!

build.gradle里的dependencies標簽頁:

如果把dependencies改成dependencies2, gradle build的輸出會遇到錯誤消息:

A problem occurred evaluating root project 'quickstart'.

Could not find method dependencies2() for arguments [build_a2307i03s3k13jdug3afl2lin$_run_closure3@21c69f73] on root project 'quickstart' of type org.gradle.api.Project.

找到這個org.gradle.api.Project類,位于目錄org\gradle\api下面:

打開Project.java, 查看關于dependencies的說明:

A project generally has a number of dependencies it needs in order to do its work. Also, a project generally * produces a number of artifacts, which other projects can use. Those dependencies are grouped in configurations, and * can be retrieved and uploaded from repositories. You use the {@link org.gradle.api.artifacts.ConfigurationContainer} * returned by {@link #getConfigurations()} method to manage the configurations. The {@link * org.gradle.api.artifacts.dsl.DependencyHandler} returned by {@link #getDependencies()} method to manage the * dependencies. The {@link org.gradle.api.artifacts.dsl.ArtifactHandler} returned by {@link #getArtifacts()} method to * manage the artifacts. The {@link org.gradle.api.artifacts.dsl.RepositoryHandler} returned by {@link * #getRepositories()} method to manage the repositories.

Project是一個接口:

里面定義了dependencies這個方法:

這個方法的實現在哪里呢?

將dependencies標簽頁里的implementation標簽隨便換個名字:

gradle build出錯:

A problem occurred evaluating root project 'quickstart'. Could not find method implementation2() for arguments [{group=commons-collections, name=commons-collections, version=3.2.2}] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.

說明Implementation標簽頁的實現就位于org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler類里.

group改成group2:

build出錯:

A problem occurred evaluating root project 'quickstart'. Could not set unknown property 'group2' for DefaultExternalModuleDependency{group='null', name='commons-collections', version='3.2.2', configuration='default'} of type org.gradle.api.internal.artifacts.dependencies.DefaultExternalModuleDependency.

所以build.gradle文件dependencies里的標簽對應了DefaultExternalModuleDependency類的實例. 前者dependencies屬性group, name和version對應了DefaultExternalModuleDependency類的成員:

再把dependenies里的group屬性值稍作修改,改成一個并不存在的庫文件名:

gradle build報錯:

Could not resolve all files for configuration ':compileClasspath'. Could not find commons-collections-:commons-collections:3.2.2. Searched in the following locations: - https://aven2/commons-collections-/commons-collections/3.2.2/commons-collections-3.2.2.pomhttps://aven2/commons-collections-/commons-collections/3.2.2/commons-collections-3.2.2.pomhttps://aven2/commons-collections/commons-collections/3.2.2/commons-collections-3.2.2.pom

到此，相信大家對“build.gradle里dependencies標簽頁的實現原理是什么”有了更深的了解，不妨來實際操作一番吧！這里是億速云網站，更多相關內容可以進入相關頻道進行查詢，關注我們，繼續學習！