日志适配扩展

<dubbo:application logger="xxx" />

-Ddubbo:application.logger=xxx

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

package com.xxx;
 
import org.apache.dubbo.common.logger.LoggerAdapter;
 
public class XxxLoggerAdapter implements LoggerAdapter {
    public Logger getLogger(URL url) {
        // ...
    }
}

package com.xxx;
 
import org.apache.dubbo.common.logger.Logger;
 
public class XxxLogger implements Logger {
    public XxxLogger(URL url) {
        // ...
    }
    public void info(String msg) {
        // ...
    }
    // ...
}

xxx=com.xxx.XxxLoggerAdapter