Help Center/ FunctionGraph/ devg/ Java/ Developing an Event Function/ Developing Functions in Java (Using an IDEA Maven Project)

Updated on 2024-11-11 GMT+08:00

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Developing Functions in Java (Using an IDEA Maven Project)

Perform the following procedure to develop a Java function:

Create a function project.

Configure the IDEA and create a Maven project, as shown in Figure 1.
Figure 1 Creating a project
Add dependencies to the project.
Download the Java SDK to a local development environment, and decompress the SDK package, as shown in Figure 2.

Figure 2 Decompressing the downloaded SDK
Copy Runtime-2.0.5.jar in the package to a local directory, for example, d:\\runtime. Then, run the following command in the CLI to install the runtime to the local Maven repository:
```
mvn install:install-file -Dfile=d:\runtime\RunTime-2.0.5.jar -DgroupId=RunTime -DartifactId=RunTime -Dversion=2.0.5 -Dpackaging=jar
```

Configure the dependency in the pom.xml file.

<dependency>
<groupId>Runtime</groupId>
<artifactId>Runtime</artifactId>
<version>2.0.5</version>
</dependency>

Configure other dependencies. The following uses the OBS dependency as an example.

<dependency>
<groupId>com.huaweicloud</groupId>
<artifactId>esdk-obs-java</artifactId>
<version>3.21.4</version>
</dependency>

Add a plug-in to pom.xml to pack the code and dependencies together.

<build>
  <plugins>
    <plugin>
      <artifactId>maven-assembly-plugin</artifactId>
      <configuration>
        <descriptorRefs>
          <descriptorRef>jar-with-dependencies</descriptorRef>
        </descriptorRefs>
        <archive>
          <manifest>
            <mainClass>com.huawei.demo.TriggerTests</mainClass>
          </manifest>
        </archive>
        <finalName>${project.name}</finalName>
      </configuration>
      <executions>
        <execution>
          <id>make-assembly</id>
          <phase>package</phase>
          <goals><goal>single</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

Replace mainClass with the actual class.

Create a function.

Create a package named com.huawei.demo, and then create a class named TriggerTests under the package, as shown in Figure 3.
Figure 3 Creating the TriggerTests class

Define the function handler in TriggerTests.java.

       
        
          
          
            package com.huawei.demo;

import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Map;

import com.huawei.services.runtime.Context;
import com.huawei.services.runtime.entity.apig.APIGTriggerEvent;
import com.huawei.services.runtime.entity.apig.APIGTriggerResponse;
import com.huawei.services.runtime.entity.dis.DISTriggerEvent;
import com.huawei.services.runtime.entity.dms.DMSTriggerEvent;
import com.huawei.services.runtime.entity.lts.LTSTriggerEvent;
import com.huawei.services.runtime.entity.smn.SMNTriggerEvent;
import com.huawei.services.runtime.entity.timer.TimerTriggerEvent;

public class TriggerTests {
    public APIGTriggerResponse apigTest(APIGTriggerEvent event, Context context){
        System.out.println(event);
        Map<String, String> headers = new HashMap<String, String>();
        headers.put("Content-Type", "application/json");
        return new APIGTriggerResponse(200, headers, event.toString());
    }

    public String smnTest(SMNTriggerEvent event, Context context){
        System.out.println(event);
        return "ok";
    }

    public String dmsTest(DMSTriggerEvent event, Context context){
        System.out.println(event);
        return "ok";
    }

    public String timerTest(TimerTriggerEvent event, Context context){
        System.out.println(event);
        return "ok";
    }

    public String disTest(DISTriggerEvent event, Context context) throws UnsupportedEncodingException{
        System.out.println(event);
        System.out.println(event.getMessage().getRecords()[0].getRawData());
        return "ok";
    }

    public String ltsTest(LTSTriggerEvent event, Context context) throws UnsupportedEncodingException {
        System.out.println(event);
        event.getLts().getData();
        System.out.println("raw data: " + event.getLts().getRawData());
        return "ok";
    }
}

           

         

       
      

For details about the constraints for the APIG event source, see Base64 Decoding and Response Structure.

Compile and pack the project file.

Run the following command to compile and pack the project file:
```
mvn package assembly:single
```
After compilation is complete, the demo-jar-with-dependencies.jar file is generated in the target directory.
Log in to the FunctionGraph console, create a Java function, and upload the JAR file.
Test the function.
1. Create a test event.
  Select timer-event-template from the Event Template drop-down list and click Create.
2. Click Test.
  The function execution result consists of three parts: function output (returned by callback), summary, and log (output by using the System.out.println() method).