想让"System.out.println()"将消息打印到log4j

import org.apache.log4j.Logger;

public class MyClass {
    private static Logger logger = Logger.getLogger(MyClass.class);

    public static void main(String[] args) {
        logger.info("This is a log message.");
    }
}

import org.apache.log4j.Logger;

public class MyClass {
    private static Logger logger = Logger.getLogger(MyClass.class);

    public static void main(String[] args) {
        logger.info("This is a log message.");
        logger.error("This is an error message.");
    }
}