<dubbo:protocol page="xxx,yyy" />
<!-- The default value setting, when <dubbo:protocol> does not configure the page attribute, use this configuration -->
<dubbo:provider page="xxx,yyy" />

src
 |-main
    |-java
        |-com
            |-xxx
                |-XxxPageHandler.java (implement PageHandler interface)
    |-resources
        |-META-INF
            |-dubbo
                |-org.apache.dubbo.container.page.PageHandler (plain text file, content: xxx=com.xxx.XxxPageHandler)

package com.xxx;
 
import org.apache.dubbo.container.page.PageHandler;
 
public class XxxPageHandler implements PageHandler {
    public Group lookup(URL url) {
        //...
    }
}

xxx=com.xxx.XxxPageHandler