Java – sharing POJO entity data classes between Android and spring projects

How to reference, add and link without copy / paste, depending on Java classes defined in different projects or libraries?

For:

> Android Studio > IntelliJ IDEA

resolvent:

Android Studio

AndroidProjectRoot / settings.gradle

before

include ':app'

after

include ':app', ':common'
project(':common').projectDir = new File('../common')

Android projectroot / build.gradle

before

apply plugin: 'com.android.application'
android {
  ...
}

dependencies {
}

after

apply plugin: 'com.android.application'
android {
  ...
}

dependencies {
    compile project(':common')
}

And then

>Tools – > Android – > synchronize projects using gradle files

Allow Android studio projects to reference external projects (at the same directory level as Android projectroot /) without copying Java libraries in Android projects

Library plan / module

You need a basic build.gradle for a library / module. The following is enough. Dependencies are only for example (only used when appropriate) in case your module is a pile of objects handled by a Dao like ormlite

Library project root / build.gradle

apply plugin: 'java'

sourceCompatibility = JavaVersion.VERSION_1_7
targetCompatibility = JavaVersion.VERSION_1_7

repositories {
    mavenCentral()
}

dependencies {
    compile 'com.j256.ormlite:ormlite-core:4.48'
    compile 'com.j256.ormlite:ormlite-android:4.48'
    compile 'com.j256.ormlite:ormlite-jdbc:4.48'
}

IntelliJ IDEA

Reference library as module

>File – > project structure > (left column) select "module" > (middle column, upper left corner) click button > import module > select the top-level directory containing Java libraries, such as common (see note below) > click "OK"

Add dependencies so that you can use the import statement

>(middle column, module list) select the main module (not the module you just added) > (rectangular area on the right, lower left corner) click the button > select 3 module dependencies... > select the module you added (e.g. common) > click OK > click OK (close the project structure) > idea should now rebuild gradle and add your library as a module to the project structure, Next to the name is a folder icon (with a small blue square)

be careful:

If your library structure is as follows:

Common / common / build.gradle common / SRC directory public / SRC / Java public / SRC / Java / main common / SRC directory / Java / main / COM common / SRC directory / Java / main / COM / your common / SRC directory / Java / main / COM / you / package general / SRC directory / Java / main / COM / you / package / yourclass.java

Further reading

Mathias Hauser – Spring Boot JPA Multiple Projects