Gradle Init

我们使用 gradle init 命令来创建java类库。

在任意位置新建文件夹 “javaLib”
打开命令行工具，将目录切换到 “javaLib” 下。

执行命令：gradle init

Select type of project to generate:
  1: basic
  2: cpp-application
  3: cpp-library
  4: groovy-application
  5: groovy-library
  6: java-application
  7: java-library
  8: kotlin-application
  9: kotlin-library
  10: scala-library
Enter selection (default: basic) [1..10] 7

我们选择要创建的项目类型，我们输入7，后面就一直使用默认配置即可。

Select build script DSL:
  1: groovy
  2: kotlin
Enter selection (default: groovy) [1..2]
Select test framework:
  1: junit
  2: testng
  3: spock
Enter selection (default: junit) [1..3]
Project name (default: javaLib):
Source package (default: javaLib):
BUILD SUCCESSFUL in 39s
2 actionable tasks: 2 executed

这样一个简单的java类库就创建完毕了。

类库默认配置

java库创建完毕后，我们观察一下其默认配置情况。

settings.gradle

rootProject.name = 'javaLib'

在 settings.gradle 下配置了我们的根项目名称。

build.gradle

plugins {
    // Apply the java-library plugin to add support for Java Library
    id 'java-library'
}
repositories {
    // Use jcenter for resolving your dependencies.
    // You can declare any Maven/Ivy/file repository here.
    jcenter()
}
dependencies {
    // This dependency is exported to consumers, that is to say found on their compile classpath.
    api 'org.apache.commons:commons-math3:3.6.1'
    // This dependency is used internally, and not exposed to consumers on their own compile classpath.
    implementation 'com.google.guava:guava:27.0.1-jre'
    // Use JUnit test framework
    testImplementation 'junit:junit:4.12'
}

在 build.gradle 下配置了 “java-library” 插件，还有仓库，以及项目依赖的其它库。

生成jar包

执行gradlew build命令即可。生成的jar包在目录 javaLib\build\libs 下。
jar包名称为：javaLib.jar

为jar包指定版本号

修改 build.gradle 文件，添加一行设置 version = '0.1.0'

build.gradle

plugins {
    // Apply the java-library plugin to add support for Java Library
    id 'java-library'
}
repositories {
    // Use jcenter for resolving your dependencies.
    // You can declare any Maven/Ivy/file repository here.
    jcenter()
}
dependencies {
    // This dependency is exported to consumers, that is to say found on their compile classpath.
    api 'org.apache.commons:commons-math3:3.6.1'
    // This dependency is used internally, and not exposed to consumers on their own compile classpath.
    implementation 'com.google.guava:guava:27.0.1-jre'
    // Use JUnit test framework
    testImplementation 'junit:junit:4.12'
}
gl>version = '0.1.0'

重新运行命令 gradlew build,在目录 javaLib\build\libs 下会生成一个名为“javaLib-0.1.0.jar”的文件。

为jar包的Meta信息添加版本号

修改 build.gradle 文件，添加如下高亮代码：

build.gradle

plugins {
    // Apply the java-library plugin to add support for Java Library
    id 'java-library'
}
repositories {
    // Use jcenter for resolving your dependencies.
    // You can declare any Maven/Ivy/file repository here.
    jcenter()
}
dependencies {
    // This dependency is exported to consumers, that is to say found on their compile classpath.
    api 'org.apache.commons:commons-math3:3.6.1'
    // This dependency is used internally, and not exposed to consumers on their own compile classpath.
    implementation 'com.google.guava:guava:27.0.1-jre'
    // Use JUnit test framework
    testImplementation 'junit:junit:4.12'
}
version = '0.1.0'
gl>jar {
gl>    manifest {
gl>        attributes('Implementation-Title': project.name,
gl>                   'Implementation-Version': project.version)
gl>    }
gl>}

重新运行命令 gradlew build
打开javaLib-0.1.0.jar文件，javaLib-0.1.0\META-INF\MANIFEST.MF 内容如下：

Manifest-Version: 1.0
Implementation-Title: javaLib
Implementation-Version: 0.1.0

生成JavaDoc

运行命令gradlew javadoc，在目录javaLib\build\docs\javadoc下就会看到生成的doc文档。打开下面的 index.html 即可。