If the Message is annotated withAsynchronouslyFormattable, it can be passed to another thread as is.
Otherwise, asynchronous logging components in the Log4j implementation will callMessage.getFormattedMessage()before passing the Message object to another thread. This gives the Message implementation class a chance to create a formatted message String with the current value of the mutable object. The intention is that the Message implementation caches this formatted message and returns it on subsequent calls.
所以只需要创建自己的扩展消息类型,用@AsynchronouslyFormattable修饰即可
@AsynchronouslyFormattable
public class ExtendObjectParameterizedMessage implements Message {
private final transient Object obj;
private transient String objectString;
private final transient Function
Description:插入大量测试数据
use xmpl;
drop procedure if exists mockup_test_data_sp;
create procedure mockup_test_data_sp(
in number_of_records int
)
begin
declare cnt int;
declare name varch
MYSQL的随机抽取实现方法。举个例子,要从tablename表中随机提取一条记录,大家一般的写法就是:SELECT * FROM tablename ORDER BY RAND() LIMIT 1。但是,后来我查了一下MYSQL的官方手册,里面针对RAND()的提示大概意思就是,在ORDER BY从句里面不能使用RAND()函数,因为这样会导致数据列被多次扫描。但是在MYSQL 3.23版本中,