SAP ABAP ADBC和Java JDBC的使用比较

Horst Keller has already introduced ADBC in his blog ABAP Geek 15 – ADBC long times ago. And recently during my self study on PostgreSQL I made some practice to connect PostgreSQL in Java programming using Java Database Connectivity – JDBC. In fact I found out that there are lots of commonality between these two technologies.

There is a demo program demo_adbc_query mentioned in SAP help to demonstrate the use of ADBC.

I make some changes on it in order to perform a line-by-line comparison with JDBC.
The source code of adapted program:

REPORT zjerry_adbc.

CLASS demo DEFINITION.
  PUBLIC SECTION.
    CLASS-METHODS main.
  PRIVATE SECTION.
    CLASS-DATA: BEGIN OF result_line,
                  carrid TYPE sflight-carrid,
                  connid TYPE sflight-connid,
                  fldate TYPE sflight-fldate,
                END OF result_line,
                result_tab LIKE TABLE OF result_line.
ENDCLASS.

CLASS demo IMPLEMENTATION.
  METHOD main.
    DATA: carrid    TYPE sflight-carrid VALUE 'AA',
          cols      TYPE adbc_column_tab,
          lv_carrid TYPE string,
          con_ref   TYPE REF TO cl_sql_connection,
          con_name  TYPE dbcon-con_name VALUE 'DEFAULT'.

    cols = VALUE #( ( CONV adbc_name( 'CARRID' ) )
                    ( CONV adbc_name( 'CONNID' ) )
                    ( CONV adbc_name( 'FLDATE' ) ) ).
    lv_carrid = cl_abap_dyn_prg=>quote( to_upper( carrid ) ).
    TRY.
        con_ref = cl_sql_connection=>get_connection( con_name ).
        DATA(statement) = con_ref->create_statement( ).
        DATA(lv_query) = `SELECT carrid, connid, fldate ` &&
         `FROM sflight ` &&
         `WHERE mandt  = ` && `'` && sy-mandt && `' AND` &&
         `      carrid = ` &&  lv_carrid.
        DATA(result) = statement->execute_query( lv_query ).
        result->set_param_table( itab_ref = REF #( result_tab )
                                 corresponding_fields = cols ).
        IF result->next_package( ) > 0.
          SORT result_tab BY carrid connid fldate.
          WRITE:/ 'Number of lines found: ', lines( result_tab ).
        ENDIF.
        con_ref->close( ).
      CATCH cx_sql_exception INTO DATA(err).
    ENDTRY.
  ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.
  demo=>main( ).

And now have a look at how JDBC can achieve the same.

I have replicated an ABAP table COMM_PRODUCT to my local PostgreSQL server:

And I manually inserted two test records into it:

Both is the source code implemented in Java to perform a query against this table and display result：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
public class PostgreSQLJDBC {
	private Connection connection = null;
	private void select() {
		try {
			int index = 0;
			Class.forName("org.postgresql.Driver");
			connection = DriverManager.getConnection(
					"jdbc:postgresql://localhost:9812/zproduct", "postgres", "XXXXXX");
			Statement stmt = connection.createStatement();
			String query = "SELECT * FROM public.comm_product;";
			ResultSet rs = stmt.executeQuery(query);
	         while ( rs.next() ) {
	        	System.out.println("Row index: " + index++);
	        	String  client = rs.getString("client");
	            System.out.println("Client: " + client);
	            String  guid = rs.getString("product_guid");
	            System.out.println("Product guid: " + guid);
	            Timestamp validFrom = rs.getTimestamp("valid_from");
	            System.out.println("Valid from: " + validFrom);
	         }
	         rs.close();
	         stmt.close();
	         connection.close();
		} catch (Exception e) {
			e.printStackTrace();
		} 
	}
	public static void main(String args[]) {
		PostgreSQLJDBC jdbcTest = new PostgreSQLJDBC();
		jdbcTest.select();
	}
}

Output in console:

And I mark the corresponding part in both language which has the same semantic meaning with same color ( although grammar is different ).

Through this comparison we can know that both connectivity technology follow the same idea.

Further reading

I have written a series of blogs which compare the language feature among ABAP, JavaScript and Java. You can find a list of them below:

• Lazy Loading, Singleton and Bridge design pattern in JavaScript and in ABAP
• Functional programming – Simulate Curry in ABAP
• Functional Programming – Try Reduce in JavaScript and in ABAP
• Simulate Mockito in ABAP
• A simulation of Java Spring dependency injection annotation @Inject in ABAP
• Singleton bypass – ABAP and Java
• Weak reference in ABAP and Java
• Fibonacci Sequence in ES5, ES6 and ABAP
• Java byte code and ABAP Load
• How to write a correct program rejected by compiler: Exception handling in Java and in ABAP
• An small example to learn Garbage collection in Java and in ABAP
• String Template in ABAP, ES6, Angular and React
• Try to access static private attribute via ABAP RTTI and Java Reflection
• Local class in ABAP, Java and JavaScript
• Integer in ABAP, Java and JavaScript
• Covariance in Java and simulation in ABAP
• Various Proxy Design Pattern implementation variants in Java and ABAP
• Tag(Marker) Interface in ABAP and Java
• Bitwise operation ( OR, AND, XOR ) on ABAP Integer
• ABAP ICF handler and Java Servlet
• ADBC and JDBC
• CL_ABAP_CORRESPONDING, CL_JAVA_CORRESPONDING and CL_JS_CORRESPONDING
• Build an Cross Site Scripting example in Java and ABAP
• Play around with JSONP in nodeJS server and ABAP server

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