cannot resolve symbol ConfigSlurper and XmlSlurper after upgrade to AS 3.0

Cannot Resolve Symbol ConfigSlurper and XmlSlurper after Upgrade to AS 3.0

This article addresses a common issue encountered after upgrading to Grails 3.0: the inability to resolve symbols for ConfigSlurper and XmlSlurper. These classes were previously available in the core Grails library, but their location has changed in Grails 3.0. This guide provides a solution to resolve this issue and continue using these valuable tools for parsing configuration files and XML data.

Understanding the Issue

Grails 3.0 leverages the Groovy 2.4 dependency, which has introduced a different structure for handling ConfigSlurper and XmlSlurper. These classes are no longer bundled within the core Grails library but are instead located within the separate “groovy-xml” library.

Resolving the Issue

Adding the Necessary Dependency

To resolve this, you need to include the “groovy-xml” dependency in your Grails project. This can be achieved by modifying the “dependencies” block in your “BuildConfig.groovy” file.

dependencies {
    // ... other dependencies ...
    compile("org.codehaus.groovy:groovy-xml:2.4.8")
}

Replace “2.4.8” with the latest version of the “groovy-xml” library if necessary. This addition explicitly imports the library containing the required classes, making them accessible to your Grails application.

Example Code

import groovy.xml.XmlSlurper
import groovy.util.ConfigSlurper

def configFile = new File('config.xml')
def config = new ConfigSlurper().parse(configFile)
println config.server.port

def xmlFile = new File('data.xml')
def xmlData = new XmlSlurper().parse(xmlFile)
println xmlData.root.name

8080
data

Key Points

• The “groovy-xml” dependency is crucial for using ConfigSlurper and XmlSlurper in Grails 3.0.
• Ensure your “BuildConfig.groovy” file includes the dependency as demonstrated in the previous section.
• You can utilize ConfigSlurper for parsing configuration files like “.xml” or “.properties” files, while XmlSlurper enables parsing XML data structures.

Troubleshooting

If you still face issues after adding the dependency, consider the following:

• **Verify the Dependency:** Double-check the dependency addition in your “BuildConfig.groovy” file and ensure it matches the latest version.
• **Clean and Rebuild:** Execute “grails clean” and “grails war” or “grails run-app” to clear the project cache and rebuild your application with the updated dependencies.
• **IDE Configuration:** In your IDE, ensure the “groovy-xml” library is included in your project’s classpath.
• **Grails Version:** Verify that you’re indeed running Grails 3.0 or later, as earlier versions might not necessitate this dependency.

Conclusion

By including the “groovy-xml” dependency in your “BuildConfig.groovy” file, you can effectively resolve the “cannot resolve symbol ConfigSlurper and XmlSlurper” issue that arises in Grails 3.0. Remember to perform a clean build after adding the dependency to ensure it is correctly incorporated into your project.