Spring - using static final fields (constants) for bean initialization

Question

is it possible to define a bean with the use of static final fields of CoreProtocolPNames class like this:

---

Answer 1

One more example to add for the instance above. This is how you can use a static constant in a bean using Spring.

<bean id="foo1" class="Foo">
  <property name="someOrgValue">
    <util:constant static-field="org.example.Bar.myValue"/>
  </property>
</bean>

package org.example;

public class Bar {
  public static String myValue = "SOME_CONSTANT";
}

package someorg.example;

public class Foo {
    String someOrgValue; 
    foo(String value){
        this.someOrgValue = value;
    }
}

Answer 2

don't forget to specify the schema location..

<?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"
   xsi:schemaLocation="
     http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
     http://www.springframework.org/schema/util  http://www.springframework.org/schema/util/spring-util-3.1.xsd">


</beans>

Answer 3

<util:constant id="MANAGER"
        static-field="EmployeeDTO.MANAGER" />

<util:constant id="DIRECTOR"
    static-field="EmployeeDTO.DIRECTOR" />

<!-- Use the static final bean constants here -->
<bean name="employeeTypeWrapper" class="ClassName">
    <property name="manager" ref="MANAGER" />
    <property name="director" ref="DIRECTOR" />
</bean>

Answer 4

Something like this (Spring 2.5)

<bean id="foo" class="Bar">
    <property name="myValue">
        <util:constant static-field="java.lang.Integer.MAX_VALUE"/>
    </property>
</bean>

Where util namespace is from xmlns:util="http://www.springframework.org/schema/util"

But for Spring 3, it would be cleaner to use the @Value annotation and the expression language. Which looks like this:

public class Bar {
    @Value("T(java.lang.Integer).MAX_VALUE")
    private Integer myValue;
}

Answer 5

Or, as an alternative, using Spring EL directly in XML:

<bean id="foo1" class="Foo" p:someOrgValue="#{T(org.example.Bar).myValue}"/>

This has the additional advantage of working with namespace configuration:

<tx:annotation-driven order="#{T(org.example.Bar).myValue}"/>