Mastering Spring XML Configuration: 9 Essential Settings Explained

1. Declare XML namespaces and schema

In Spring XML files you must declare the XML namespace and XML Schema to use Spring tags and attributes.

<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.xsd">
    <!-- configuration content -->
</beans>

xmlns

declares the XML namespace. xsi declares the XML Schema instance namespace. xsi:schemaLocation points to the schema file.

2. Declare a bean

Use the <bean> element to define a bean’s id, class and other attributes.

<bean id="helloWorld" class="com.mikechen.HelloWorld">
    <property name="message" value="Hello World!" />
</bean>

Attributes: id: unique identifier in the container. class: fully‑qualified class name.

3. Set bean properties

Use <property> to inject values or references.

<bean id="userDao" class="com.example.UserDao">
    <property name="dataSource" ref="dataSource" />
</bean>

4. Define bean scope

The scope attribute controls the lifecycle, e.g., singleton (default) or prototype.

<bean id="userService" class="com.example.UserService" scope="prototype">
    <!-- configuration content -->
</bean>

5. Declare dependencies

Constructor injection uses <constructor-arg>, while property injection uses <property>.

<bean id="userRepository" class="com.example.UserRepository">
    <constructor-arg value="jdbc:mysql://localhost:3306/mydb" />
    <constructor-arg value="root" />
    <constructor-arg value="password" />
</bean>

6. Configure AOP

Use <aop:config> with <aop:aspect>, <aop:pointcut> and advice elements.

<aop:config>
    <aop:aspect ref="loggingAspect">
        <aop:pointcut id="userServicePointcut"
                      expression="execution(* com.example.UserService.*(..))" />
        <aop:before pointcut-ref="userServicePointcut" method="beforeAdvice" />
    </aop:aspect>
</aop:config>

7. Configure transactions

Use <tx:advice> to apply transaction attributes to methods.

<tx:advice id="txAdvice" transaction-manager="transactionManager">
    <tx:attributes>
        <tx:method name="*" propagation="REQUIRED" />
    </tx:attributes>
</tx:advice>

8. Import other XML files

The <import> element allows you to include additional configuration files.

9. Component scanning

<context:component-scan>

automatically detects annotated classes and registers them as beans.