In the below code example shows how the Spring JDBCTemplate simplifies the code to perform the database-related operations.
The complete examples running code is available to download from Github
DAO Interface:
package com.spring.jdbc;
import java.util.List;
/**
*
* @author codedairy
*/
public interface CustomerDAO {
public Customer getCustomer(Integer customerId);
public int createCustomer(Customer newCustomer);
public List retrieveAllCustomers();
}
Implementation of our DAO class
package com.spring.jdbc;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
/**
*
* @author codedairy
*/
public class CustomerDAOImpl implements CustomerDAO {
private JdbcTemplate jdbcTemplate;
private final String select = "SELECT * FROM CUSTOMER WHERE ID= ?";
private final String insert = "INSERT INTO CUSTOMER( NAME, AGE) VALUES(?,?)";
private final String retrieveall = "SELECT * FROM CUSTOMER";
@Override
public Customer getCustomer(Integer customerId) {
Customer c = (Customer)getJdbcTemplate().queryForObject(select, new Object[]{customerId}, new RowMapper() {
@Override
public Customer mapRow(ResultSet rs, int i) throws SQLException {
Customer cust = new Customer();
cust.setId(new Integer(rs.getString("ID")));
cust.setName(rs.getString("NAME"));
cust.setAge(new Integer(rs.getString("AGE")));
return cust;
}
});
return c;
}
@Override
public int createCustomer(Customer newCustomer) {
return getJdbcTemplate().update(insert, new Object[]{newCustomer.getName(),newCustomer.getAge()});
}
@Override
public List retrieveAllCustomers() {
List<Map> list = getJdbcTemplate().queryForList(retrieveall);
List custList = new ArrayList();
for(Iterator itr = list.iterator(); itr.hasNext();){
Map map = (Map) itr.next();
Integer id = (Integer) map.get("ID");
String name = (String)map.get("NAME");
Integer age = (Integer)map.get("AGE");
Customer cust = new Customer(id,name,age);
custList.add(cust);
}
return custList;
}
public JdbcTemplate getJdbcTemplate() {
return jdbcTemplate;
}
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
}
Our Main executable class is:
package com.spring.jdbc.test;
import com.spring.jdbc.Customer;
import com.spring.jdbc.CustomerDAO;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
*
* @author codedairy
*/
public class CustomerExec {
public static void main(String args[]){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("customer_jdbc.xml");
CustomerDAO customerDAO = (CustomerDAO) applicationContext.getBean("customerdao");
Customer customer = new Customer();
customer.setAge(20);
customer.setName("Roger Chick");
Customer customer1 = new Customer();
customer1.setAge(30);
customer1.setName("Stephen Hardy");
Customer customer2 = new Customer();
customer2.setAge(30);
customer2.setName("Kuldip Bajwa");
//CREATE CUSTOMER RECORD EXAMPLE
System.out.println("Rows affected: " + customerDAO.createCustomer(customer));
System.out.println("Rows affected: " + customerDAO.createCustomer(customer1));
//RETRIEVE CUSTOMER RECORDS EXAMPLE
System.out.println("CUSTOMER TABLE RECORDS: "+customerDAO.retrieveAllCustomers().toString());
//QUERYING A PARTICULAR RECORD FROM CUSTOMER TABLE - For e.g., by Customer ID
System.out.println("Record Found: \n" + customerDAO.getCustomer(3).toString());
}
}