如何正确定位 Spring Context 属性占位符？

Question

I am attempting to implement an outdated open-source Properties File Manager ( https://github.com/Confluex/Zuul/wiki ) with a Mule Test Application in MuleSoft's Anypoint Studio platform. This appears to require the Spring Context Schema, but the project cannot locate it. It continually states there is no 'context:property-placeholder'. I feel a versioning error may be the problem. Here is my attempt:

<mule 
    xmlns="http://www.mulesoft.org/schema/mule/core" 
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:spring="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:zuul="zuul-spring-client-1.5.1"
    xsi:schemaLocation="
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
zuul-spring-client-1.5.1 zuul-spring-client-1.5.1.xsd">


        <context:property-placeholder properties-ref="MuleMeetZuul" />
    
</mule>

Here is the error thrown:

Caused by: org.mule.runtime.api.exception.MuleRuntimeException: There was '1' error while parsing the given file 'zuultest.xml'.
Full list:
org.xml.sax.SAXParseException; lineNumber: 17; columnNumber: 65; cvc-complex-type.2.4.a: Invalid content was found starting with element 'context:property-placeholder'. One of '{"http://www.mulesoft.org/schema/mule/core":annotations, "http://www.mulesoft.org/schema/mule/core":description, "http://www.mulesoft.org/schema/mule/core":global-property, "http://www.mulesoft.org/schema/mule/core":configuration, "http://www.mulesoft.org/schema/mule/core":notifications, "http://www.mulesoft.org/schema/mule/core":abstract-extension, "http://www.mulesoft.org/schema/mule/core":abstract-shared-extension, "http://www.mulesoft.org/schema/mule/core":abstract-mixed-content-extension, "http://www.mulesoft.org/schema/mule/core":abstract-security-manager, "http://www.mulesoft.org/schema/mule/core":abstract-transaction-manager, "http://www.mulesoft.org/schema/mule/core":abstract-shared-transaction-manager, "http://www.mulesoft.org/schema/mule/core":abstract-connector, "http://www.mulesoft.org/schema/mule/core":abstract-shared-connector, "http://www.mulesoft.org/schema/mule/core":abstract-global-endpoint, "http://www.mulesoft.org/schema/mule/core":abstract-exception-strategy, "http://www.mulesoft.org/schema/mule/core":abstract-on-error, "http://www.mulesoft.org/schema/mule/core":abstract-flow-construct, "http://www.mulesoft.org/schema/mule/core":flow, "http://www.mulesoft.org/schema/mule/core":sub-flow, "http://www.mulesoft.org/schema/mule/core":top-level-processor, "http://www.mulesoft.org/schema/mule/core":abstract-global-intercepting-message-processor, "http://www.mulesoft.org/schema/mule/core":abstract-object-store}' is expected.

Any advice would be much appreciated. Thanks.

Answer 1

If you are trying to use the Mule 3 implementation in a Mule 4 it will fail, and that should be expected. Mule 3 property placeholder providers where directly Spring property placeholder providers. Mule 4 uses a different way to implement them. <context:property-placeholder> doesn't exist in Mule 4. Its replacement <configuration-properties> will not work for this usage.

Instead you will have to use Mule SDK for Java to develop a custom configuration property provider by implementing the ConfigurationPropertiesProviderFactory interface in a factory class and extending the DefaultConfigurationPropertiesProvider class to implement the provider. In the provider you will need to use the Zuul library to implement the operations to get the keys and values.

Instructions are available in the documentation: https://docs.mulesoft.com/mule-runtime/4.3/custom-configuration-properties-provider