Java Connector(JCO)环境的搭建：Step by step to download and configure JCO in your laptop
我的ABAP系统有个函数名叫ZDIS_GET_UPSELL_MATERIALS，输入一个customer ID和product ID，会输出为这对客户和product组合维护的一组Upsell product ID和描述信息。
测试如下：

下面是使用Java消费该函数的代码：

package jco; import java.io.File; import java.io.FileOutputStream; import java.util.Properties; import com.sap.conn.jco.JCoDestination; import com.sap.conn.jco.JCoDestinationManager; import com.sap.conn.jco.JCoException; import com.sap.conn.jco.JCoFunction; import com.sap.conn.jco.JCoParameterList; import com.sap.conn.jco.JCoRepository; import com.sap.conn.jco.JCoTable; import com.sap.conn.jco.ext.DestinationDataProvider; /**
 * basic examples for Java to ABAP communication  
 * See help: https://help.sap.com/saphelp_nwpi711/helpdata/en/48/70792c872c1b5ae10000000a42189c/frameset.htm
 */ public class StepByStepClient { static String DESTINATION_NAME = "ABAP_AS_WITHOUT_POOL"; static public final String ABAP_DURATION = "abapLayerDuration"; static public final String UPSELL_PRODUCT = "upsellProducts"; static public final String PRODUCT_ID = "productID"; static public final String PRODUCT_TEXT = "productText"; static private Properties prepareProperty(){
        Properties connectProperties = new Properties();
        connectProperties.setProperty(DestinationDataProvider.JCO_ASHOST, "ldcixcd.wdf.sap.corp");
        connectProperties.setProperty(DestinationDataProvider.JCO_SYSNR, "00");
        connectProperties.setProperty(DestinationDataProvider.JCO_CLIENT, "111");
        connectProperties.setProperty(DestinationDataProvider.JCO_USER, "WANGJER");
        connectProperties.setProperty(DestinationDataProvider.JCO_PASSWD, "Saptest1");
        connectProperties.setProperty(DestinationDataProvider.JCO_LANG, "en");
        createDestinationDataFile(DESTINATION_NAME, connectProperties);
        connectProperties.setProperty(DestinationDataProvider.JCO_POOL_CAPACITY, "3");
        connectProperties.setProperty(DestinationDataProvider.JCO_PEAK_LIMIT, "10");
        createDestinationDataFile(DESTINATION_NAME, connectProperties); return connectProperties;
    } static public void main(String[] arg) {
        createDestinationDataFile(DESTINATION_NAME, prepareProperty());
        
        JCoDestination destination = null; try {
            destination = JCoDestinationManager.getDestination(DESTINATION_NAME);
            JCoRepository repo = destination.getRepository();
            JCoFunction stfcConnection = repo.getFunction("ZDIS_GET_UPSELL_MATERIALS");

            JCoParameterList imports = stfcConnection.getImportParameterList();
        
            String customerID = "1000040";
            String materialID = "11";

            imports.setValue("IV_CUSTOMER_ID", customerID);
            imports.setValue("IV_MATERIAL_ID", materialID);

            stfcConnection.execute(destination);
        
            JCoParameterList exports = stfcConnection.getExportParameterList(); // int result = exports.getInt("EV_RESULT"); int abapDuration = exports.getInt("EV_DURATION");
            
            StringBuilder sb = new StringBuilder();
            sb.append("{ \"" + ABAP_DURATION + "\": " + abapDuration + ",");
            
            sb.append("\"" + UPSELL_PRODUCT + "\":[");
            
            JCoTable codes = exports.getTable("ET_MATERIALS"); int row = codes.getNumRows();
            System.out.println("Total rows: " + row);
            
            System.out.println("ABAP duration: " + abapDuration); for( int i = 0; i < row; i++){
                codes.setRow(i);
                System.out.println(codes.getString("MATERIAL_ID") + '\t' + codes.getString("MATERIAL_TEXT"));
                sb.append("{\"" + PRODUCT_ID + "\":" + codes.getString("MATERIAL_ID") + "," + "\"" + PRODUCT_TEXT + "\":\"" + codes.getString("MATERIAL_TEXT") + "\""); if( i < row - 1){
                    sb.append("},");
                } else{
                    sb.append("}");
                }
            }
            sb.append("]}");
            
            System.out.println("Final json: " + sb.toString());
            
        } catch (JCoException e) { // TODO Auto-generated catch block e.printStackTrace();
        }
        
    } static private void createDestinationDataFile(String destinationName, Properties connectProperties) {
        File destCfg = new File(destinationName+".jcoDestination"); try {
            FileOutputStream fos = new FileOutputStream(destCfg, false);
            connectProperties.store(fos, "for tests only !");
            fos.close();
        } catch (Exception e)
        { throw new RuntimeException("Unable to create the destination files", e);
        }
    } 
} 

为简单起见没有使用Google的gson库进行Json的序列化。
执行结果：

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