ResultSetExtractor With Aggregate Function : ResultSetExtractor « Spring « Java Tutorial

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2. Spring
3. ResultSetExtractor

File: context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:util="http://www.springframework.org/schema/util"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:lang="http://www.springframework.org/schema/lang"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
                           http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.0.xsd
                           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
                           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
                           http://www.springframework.org/schema/lang http://www.springframework.org/schema/lang/spring-lang-2.0.xsd">

<!--
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/>
        <property name="url" value="jdbc:oracle:thin:@oracle.devcake.co.uk:1521:INTL"/>
        <property name="username" value="sa"/>
        <property name="password" value=""/>
    </bean>
-->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="org.hsqldb.jdbcDriver"/>
    <property name="url" value="jdbc:hsqldb:mem:."/>
    <property name="username" value="sa"/>
    <property name="password" value=""/>
    </bean>
<!--
    <bean id="mysqlDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://dbhost-prospring-psql/prospring"/>
        <property name="username" value="sa"/>
        <property name="password" value=""/>
    </bean>
-->
    <bean id="lobHandler" class="org.springframework.jdbc.support.lob.OracleLobHandler">
        <property name="nativeJdbcExtractor" ref="nativeJdbcExtractor"/>
    </bean>

    <bean id="nativeJdbcExtractor" class="org.springframework.jdbc.support.nativejdbc.CommonsDbcpNativeJdbcExtractor"/>

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>


</beans>

File: Main.java

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.dao.DataAccessException;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.ResultSetExtractor;

class Main {
  public static void main(String args[]) throws Exception {
    ApplicationContext ac = new ClassPathXmlApplicationContext("context.xml", Main.class);
    DataSource dataSource = (DataSource) ac.getBean("dataSource");
    // DataSource mysqlDataSource = (DataSource) ac.getBean("mysqlDataSource");

    JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);

    Long count = (Long) jdbcTemplate.query("select count(*) from customer",
        new ResultSetExtractor() {
          public Object extractData(ResultSet resultSet) throws SQLException, DataAccessException {
            if (resultSet.next()) {
              return resultSet.getLong(1);
            }
            return null;
          }
        });
    System.out.println(count);

  }
}

28.49.ResultSetExtractor
	28.49.1.	ResultSetExtractor With Aggregate Function
	28.49.2.	PreparedStatement Creator And PreparedStatement Setter
	28.49.3.	Implements ResultSetExtractor to read the data from first column