BE THE CODER > Spring > JDBC > Row Callback Handler

Spring JDBC Framework simplifies the use of JDBC and helps to avoid common errors. The following example shows using RowCallbackHandler interface. This callback interface is called once for processing each row. The CustomRowCallbackHandler given in this examples buffers the user names from each row.

File Name :	com/bethecoder/tutorials/spring3/tests/RowCallbackHandlerTest.java
Author :	Sudhakar KV
Email :	[email protected]


package com.bethecoder.tutorials.spring3.tests;



import java.sql.ResultSet;

import java.sql.SQLException;



import javax.sql.DataSource;



import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import org.springframework.jdbc.core.JdbcTemplate;

import org.springframework.jdbc.core.RowCallbackHandler;



public class RowCallbackHandlerTest {



  /**

   * @param args

   */

  public static void main(String[] args) {

    

    /**

     * Initialize context and get the JdbcTemplate

     */

    ApplicationContext appContext = new ClassPathXmlApplicationContext("applicationContext.xml");

    DataSource dataSource = (DataSource) appContext.getBean("dataSource");

    JdbcTemplate template = new JdbcTemplate(dataSource);



    CustomRowCallbackHandler handler = new CustomRowCallbackHandler();

    template.query("select * from USER", handler);

    System.out.println("Names : " + handler.getUserNames());

  }



}

//RowCallbackHandler is stateful

class CustomRowCallbackHandler implements RowCallbackHandler {

  

  private StringBuilder sb = new StringBuilder();

  

  @Override

  public void processRow(ResultSet rs) throws SQLException {

    if (sb.length() != 0) {

      sb.append(", ");

    }

    

    sb.append(rs.getString("NAME"));

  }

  

  public String getUserNames() {

    return sb.toString();

  }

}