Spring-使用静态final字段(常量)进行bean初始化 [英] Spring - using static final fields (constants) for bean initialization

问题描述

是否可以使用CoreProtocolPNames类的static final字段来定义bean，如下所示:

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

<bean id="httpParamBean" class="org.apache.http.params.HttpProtocolParamBean">
     <constructor-arg ref="httpParams"/>
     <property name="httpElementCharset" value="CoreProtocolPNames.HTTP_ELEMENT_CHARSET" />
     <property name="version" value="CoreProtocolPNames.PROTOCOL_VERSION">
</bean>

---

public interface CoreProtocolPNames {

    public static final String PROTOCOL_VERSION = "http.protocol.version"; 

    public static final String HTTP_ELEMENT_CHARSET = "http.protocol.element-charset"; 
}

---

如果可能的话，最好的方法是什么?

---

If it is possible, what is the best way of doing this ?

推荐答案

类似的东西(春季2.5)

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>

util名称空间来自xmlns:util="http://www.springframework.org/schema/util"

但是对于Spring 3，使用@Value批注和表达式语言会更干净.看起来像这样:

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;
}

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