configuring Tomcat and spring framework

add this to your web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/classes/springConfig.xml</param-value>
    </context-param>
    <listener>
        <description>domyslny listener dla sF</description>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
..
..
</web-app>

ok and now prepare your spring 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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
    <bean id="dataSource" class="org.apache.tomcat.dbcp.dbcp.BasicDataSource">
        <property name="driverClassName" value="org.postgresql.Driver"/>
        <property name="url" value="jdbc:postgresql://localhost:5432/dbname"/>
        <property name="password" value="pass"/>
        <property name="username" value="user"/>
        <property name="poolPreparedStatements"><value>true</value></property>
        <property name="maxActive"><value>10</value></property>
        <property name="maxIdle"><value>10</value></property>
    </bean>
    <bean id="injectionTest" class="pl.mypck.InjectionTest">
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

read more in spring documentation about IoC and beans http://static.springframework.org/spring/docs/2.5