Required Core Libraries

Core SAP CPI Library (Must-have)

import com.sap.gateway.ip.core.customdev.util.Message;

This is mandatory in every groovy script. It gives access to: 

 Header 

 Property 

 Body  

Java Utility Libraries

import java.util.HashMap;

import java.util.List;

import java.util.ArrayList;

import java.util.Map;

import java.util.Date;

import java.text.SimpleDateFormat;

We can use these for: 

 Working with collection 

 Date Formatting 

 General Java-style logic

XML Handling (for parsing XML) 

import groovy.xml.XmlSlurper;

import groovy.xml.XmlUtil;

import groovy.util.XmlParser;

Use when you want: 

 Parse XML body 

 Extract specific nodes/values 

 Modify or Create XML 

JSON Handling

import groovy.json.JsonSlurper;

import groovy.json.JsonOutput;

Use when your payload or part of it in JSON 

 Parse JSON in to maps/lists 

 Convert objects/maps to JSON string 

Logging (Optional but Useful) 

def messageLog = messageLogFactory.getMessageLog(message);

messageLog.addAttachmentAsString("Payload", message.getBody(String), "text/plain");

To enable logging (in Trace mode only) 

Helps in debugging during iFlow development.

Example Script using multiple libraries

import com.sap.gateway.ip.core.customdev.util.Message;

import java.util.HashMap;

import groovy.json.JsonSlurper;

import groovy.xml.XmlUtil;

def Message processData(Message message) {

    def body = message.getBody(String) 

    // Example: Parse JSON if body is JSON  

    def json = new JsonSlurper().parseText(body)

    def userId = json.UserID

    // Add new header

    message.setHeader("UserID", userId)

    return message;

}