This topic describes how to compile a program in a Java runtime environment by using Maven or Serverless Devs and package the program as a ZIP or JAR package. After the compilation and packaging, you can upload the code package by using the Function Compute console or by using Serverless Devs.

Dependency libraries of Java runtime

To create and deploy a code package, you must compile and package the function code and dependency libraries together as a ZIP package or a JAR package.

Function Compute provides the following dependency libraries for Java runtime:

You can use the Maven central repository to obtain the preceding dependencies. Obtain the preceding dependency libraries and add them to the pom.xml file. Example:

<!-- https://mvnrepository.com/artifact/com.aliyun.fc.runtime/fc-java-core -->
<dependency>
    <groupId>com.aliyun.fc.runtime</groupId>
    <artifactId>fc-java-core</artifactId>
    <version>1.4.1</version>
</dependency>

<!-- https://mvnrepository.com/artifact/com.aliyun.fc.runtime/fc-java-event -->
<dependency>
    <groupId>com.aliyun.fc.runtime</groupId>
    <artifactId>fc-java-event</artifactId>
    <version>1.2.0</version>
</dependency>
Note If the dependency package is too large, you can package the dependencies into a layer to reduce the size of the code package. For more information, see Use layers in functions.

Compile and deploy code packages by using Maven

Prerequisites

Java and Maven are installed. For more information about Java, visit the Java official website. For more information about Maven, see Installing Apache Maven.

Procedure

  1. Create a Java project that has the following directory structure:
    src/main/java/example/App.java  

    Add the following sample code to the App.java file: For the detailed code, see Event handlers, HTTP handlers, or Context object.

  2. Create the pom.xml file under the project root directory and configure build in the pom.xml file. Example:
    <build>
            <plugins>
                  <plugin>
                      <groupId>org.apache.maven.plugins</groupId>
                      <artifactId>maven-shade-plugin</artifactId>
                      <version>3.2.1</version>
                      <executions>
                        <execution>
                          <phase>package</phase>
                          <goals>
                            <goal>shade</goal>
                          </goals>
                          <configuration>
                            <filters>
                              <filter>
                                <artifact>*:*</artifact>
                                <excludes>
                                  <exclude>META-INF/*.SF</exclude>
                                  <exclude>META-INF/*.DSA</exclude>
                                  <exclude>META-INF/*.RSA</exclude>
                                </excludes>
                              </filter>
                            </filters>
                          </configuration>
                        </execution>
                      </executions>
                  </plugin>
            </plugins>
    </build>
    Note You can use Apache Maven Shade or Apache Maven Assembly. The preceding example uses only Apache Maven Shade.
  3. Open CLI and switch to the root directory of the project. Run the mvn clean package command to perform packaging.
    Sample code:
    [INFO] Scanning for projects...
     ...  ....   ....
    [INFO] --------------------------< example:example >---------------------------
    [INFO] Building java-example 1.0-SNAPSHOT
    [INFO] --------------------------------[ jar ]---------------------------------
     ...  ....   ....
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time:  11.681 s
    [INFO] Finished at: 2020-03-26T15:55:05+08:00
    [INFO] ------------------------------------------------------------------------
    • If the compilation fails, modify the code based on the error message.
    • If the compilation succeeds, the compiled JAR package is in the target directory of the project and is named as java-example-1.0-SNAPSHOT.jar based on the artifactId and version fields in pom.xml.
      Notice For macOS and Linux operating systems, make sure that the code file is readable and executable before compression.
  4. Log on to the Function Compute console. Upload the code package and click Test Function on the Code tab to test the function.

Compile and deploy code packages by using Serverless Devs

Prerequisites

Procedure

  1. Run the following command to initialize a project:
    s init devsapp/start-fc-event-java8 -d start-fc-event-java8
    • s init devsapp/start-fc-event-java8: indicates that the project is initialized based on the HTTP request handler template.
    • -d start-fc-event-java8: outputs the project file to the specified directory.

    After you run the command, select the region, service name, and function name, and configure the key as prompted.

    Note You can also run the s init command to select a template as prompted.
  2. Run the following command to go to the project directory:
    cd start-fc-event-java8
  3. Run the following command to deploy the project:
    s deploy

    When you run the command, the pre-deploy command is first executed. During the execution of the pre-deploy command, mvn package is run to perform compilation and packaging. Then upload and deploy the code package. Sample command output:

    [2022-04-07 12:00:09] [INFO] [S-CORE] - Start the pre-action
    [2022-04-07 12:00:09] [INFO] [S-CORE] - Action: mvn package
    [INFO] Scanning for projects...
    [INFO]
    [INFO] ------------------------< example:HelloFCJava >-------------------------
    [INFO] Building HelloFCJava 1.0-SNAPSHOT
    [INFO] --------------------------------[ jar ]---------------------------------
    ......
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time:  3.617 s
    [INFO] Finished at: 2022-04-07T20:00:14+08:00
    [INFO] ------------------------------------------------------------------------
    [2022-04-07 12:00:14] [INFO] [S-CORE] - End the pre-action
    
    ✔ Checking Service, Function (0.64s)
    ✔ Creating Service, Function (0.71s)
    
    Tips for next step
    ======================
    * Display information of the deployed resource: s info
    * Display metrics: s metrics
    * Display logs: s logs
    * Invoke remote function: s invoke
    * Remove Service: s remove service
    * Remove Function: s remove function
    * Remove Trigger: s remove trigger
    * Remove CustomDomain: s remove domain
    
    
    
    helloworld:
      region:   cn-hangzhou
      service:
        name: hello-world-service
      function:
        name:       start-fc-event-java8
        runtime:    java8
        handler:    example.App::handleRequest
        memorySize: 128
        timeout:    60
  4. Run the s invoke command to perform testing.
    Sample command output:
    ➜  start-fc-event-java8 s invoke
    ========= FC invoke Logs begin =========
    FC Initialize Start RequestId: b246c3bf-06bc-49e5-92b8-xxxxxxxx
    FC Initialize End RequestId: b246c3bf-06bc-49e5-92b8-xxxxxxxx
    FC Invoke Start RequestId: b246c3bf-06bc-49e5-92b8-xxxxxxxx
    FC Invoke End RequestId: b246c3bf-06bc-49e5-92b8-xxxxxxxx
    
    Duration: 7.27 ms, Billed Duration: 8 ms, Memory Size: 128 MB, Max Memory Used: 65.75 MB
    ========= FC invoke Logs end =========
    
    FC Invoke Result:
    hello world
    
    
    
    End of method: invoke