Grails中的JSON问题

Question

Im toying with grails but i'm having troubles when render JSON in the controller, i have this code

import grails.converters.*

        class CourseController {
        def index = { redirect(action:list,params:params) }
        // the delete, save and update actions only accept POST requests
            static allowedMethods = [delete:'POST', save:'POST', update:'POST']

            def list = {
                params.max = Math.min( params.max ? params.max.toInteger() : 10,  100)
                //[ courseInstanceList: Course.list( params ) , courseInstanceTotal: Course.count() ]
                def courses = Course.list( params )
                // return a bunch of json data with metadata.
                def json = [        
                     totalCount: courses.size,
                     results: courses
                ]

                render json as JSON


            }
    //other methods.... that i didn't touch
}

But when i execute the "run-app" command i get the fallowing error:

unable to resolve class org.codehaus.groovy.grails.co
mmons.metaclass.ExpandoMetaClass
 @ line 4, column 1.
   import org.codehaus.groovy.grails.commons.metaclass.ExpandoMetaClass

i really don't know why :(

Answer 1

That looks like a Grails install error - is GRAILS_HOME set properly?

Or a clash of Groovy jars - are there two versions of Groovy on the classpath somehow?