Gradle是一个构建工具，构建包括依赖管理、编译、打包等过程。总结了Gradle和maven之间的主要区别：灵活性、用户体验和依赖关系管理。

依赖管理

1.申明简洁

<!-- pom.xml scope-->
<dependencies>
<dependency>
    <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
</dependencies>

// build.gradle  configuration
dependencies {
     testCompile 'junit:junit:4.12'
}

2.依赖颗粒度

Maven	When available	Leaks into consumers’ compile time	Leaks into consumers’ runtime	Included in Artifact
compile	compile time, runtime， test， compile time, test runtime	yes	yes	yes
provided	compile time， runtime test ，compile time, test runtime	no	no	no
runtime	runtime test, runtime	no	yes	yes
test	test compile, test runtime	no	no	no
system
import

Gradle	When available	Leaks into consumers’ compile time	Leaks into consumers’ runtime	Included in Artifact
implementation	compile time, runtime test compile time, test runtime	no	yes	yes
api	compile time， runtime test compile time, test runtime	yes	no	no
compileOnly	compile time	no	no	yes
runtimeOnly	runtime	no	yes	yes
testImplementation	test compile time, test runtime	no	no	no
testCompileOnly	test compile time	no	no	no
testRuntimeOnly	test runtime	no	no	no

3.灵活性

3.1以一个常见的JAVA日志库冲突问题为例 image-20201113134242866.png

<!-- pom.xml  -->
<dependency>
      <groupId>org.apache.hive</groupId>
      <artifactId>hive-exec</artifactId>
      <version>2.1.0</version>
      <exclusions>
          <exclusion>
             <artifactId>log4j-slf4j-impl</artifactId>
              <groupId>org.apache.logging.log4j</groupId>
          </exclusion>
     </exclusions>
</dependency>

// build.gradle

// 全局排除依赖
configurations {
    // 支持通过group、module排除，可以同时使用
    all*.exclude group: 'commons-logging', module: 'commons-logging' // common-logging
    all*.exclude group: 'log4j', module: 'log4j' // log4j
    all*.exclude group: 'org.apache.logging.log4j', module: 'log4j-core' // slf4j -> log4j2
    all*.exclude group: 'org.apache.logging.log4j', module: 'log4j-slf4j-impl' // log4j2
    all*.exclude group: 'org.slf4j', module: 'slf4j-jdk14' // slf4j -> jdk-logging
    all*.exclude group: 'org.slf4j', module: 'slf4j-jcl' // slf4j -> common-logging
    all*.exclude group: 'org.slf4j', module: 'slf4j-log4j12' // slf4j -> log4j
}
// 引入依赖 所有类型的日志库都桥接到 slf4j 实现库为logback
dependencies {
    // log
    compile "org.slf4j:slf4j-api:$slf4j_version"
    compile "org.slf4j:jul-to-slf4j:$slf4j_version"
    compile "org.slf4j:jcl-over-slf4j:$slf4j_version"
    compile "org.slf4j:log4j-over-slf4j:$slf4j_version"
    compile "org.apache.logging.log4j:log4j-api:$log4j2_version"
    compile "org.apache.logging.log4j:log4j-to-slf4j:$log4j2_version"
    compile "ch.qos.logback:logback-classic:$logback_version"
}

3.2 依赖拉取缓存策略

configurations.all {
    //每隔24小时检查远程依赖是否存在更新
    resolutionStrategy.cacheChangingModulesFor 24, 'hours'
    //每隔10分钟..
    // resolutionStrategy.cacheChangingModulesFor 10, 'minutes'
    // 采用动态版本声明的依赖缓存10分钟
    // resolutionStrategy.cacheDynamicVersionsFor 10*60, 'seconds'
}

3.3 依赖传递可配置

// 依赖不传递
compile("org.springframework:spring-web:4.3.4.RELEASE") {
    transitive = false
}


configurations {
    //编译期排除commons模块
    compile.exclude module: 'commons'
    //在整个构建过程中排除pkaq.tiger：share
    all*.exclude group: 'pkaq.tiger', module: 'share'
}


dependencies {
    //当前指定依赖不传递
    compile("pkaq.tiger:web:1.0") {
        exclude module: 'share'
    }      
}

// 强制使用该版本
compile('org.hibernate:hibernate:3.1') {
    force = true
}

// 全局配置，使用版本
configurations.all {
   resolutionStrategy {
       force 'org.hamcrest:hamcrest-core:1.3'
   }
}