Log 日志

1. 获取完整的日志信息

e.getMessage() ，很多时候，并不能提供有效的异常信息

打印堆栈信息

public static String getTrace(Throwable t) {
		StringWriter stringWriter= new StringWriter();
		PrintWriter writer= new PrintWriter(stringWriter);
		t.printStackTrace(writer);
		StringBuffer buffer= stringWriter.getBuffer();
		return buffer.toString();
	}