自定义异常类一般是为了配合自定义日志用的,对程序员关注的异常信息能更有针对性,自定义异常一般都会继承
RuntimeException类.并实现其中的方法,同时将自定义异常信息向上传递给父类直至*父类Throwable

package app.base;

import org.apache.log4j.Logger;


/**
 * 
 * 
 * @author hxf
 */
public class ServiceException extends RuntimeException {
	
	private static final long serialVersionUID = 3583566093089790852L;
	
	private static Logger log = Logger.getLogger(ServiceException.class);
	
	public ServiceException() {
		super();
	}

	public ServiceException(String message) {
		super(message);
		if (log.isDebugEnabled()) {
			log.debug(message);
		}
	}

	public ServiceException(Exception cause) {		
		super(cause);
		if (log.isDebugEnabled()) {
			log.debug(cause.getMessage());
		}
	}

	public ServiceException(String message, Throwable cause) {
		super(message, cause);
		if (log.isDebugEnabled()) {
			log.debug(message);
		}
	}
}

ThrowAble会调用本地方法