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<dubbo:application compiler="jdk" />

src
 |-main
    |-java
        |-com
            |-xxx
                |-XxxExtensionFactory.java (实现ExtensionFactory接口)
    |-resources
        |-META-INF
            |-dubbo
                |-org.apache.dubbo.common.extension.ExtensionFactory (纯文本文件，内容为：xxx=com.xxx.XxxExtensionFactory)

package com.xxx;
 
import org.apache.dubbo.common.extension.ExtensionFactory;
 
public class XxxExtensionFactory implements ExtensionFactory {
    public Object getExtension(Class<?> type, String name) {
        // ...
    }
}

xxx=com.xxx.XxxExtensionFactory