学会简单使用log4j

简单配置：
### ??Logger?????????? ###
##log4j.rootLogger=debug, stdout,logfile
log4j.rootLogger=debug, stdout

### ??????????? ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.err
log4j.appender.stdout.layout=org.apache.log4j.SimpleLayout

### ???????????zs.log ###
# log4j.appender.logfile=org.apache.log4j.FileAppender
# log4j.appender.logfile.File=zs.log
# log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
# log4j.appender.logfile.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss}%l %F %p %m%n

简单使用：

public Logger log=JDBC.logger;
String sql="insert into student values ("+s.getId()+",'"+s.getName()+"',"+s.getAge()+",'"+s.getEmail()+"','"+s.getBirth()+"');";
        try {
            log.info(sql);