http://log4mongo.org/display/PUB/Log4mongo+for+Java
保存主机信息，方法等
http://my.oschina.net/chinaearl/blog/111552
只保存输出信息
http://www.myexception.cn/program/650442.html
配置
log4j.appender.MongoDB=org.log4mongo.MongoDbPatternLayoutAppender
log4j.appender.MongoDB.databaseName=appname
log4j.appender.MongoDB.collectionName=log
log4j.appender.MongoDB.hostname=10.22.196.88
log4j.appender.MongoDB.port=9933
log4j.appender.MongoDB.layout=org.log4mongo.MongoDbPatternLayout
类
private static final Logger LOGGER = Logger.getLogger("MongoDB");
public static void main(String[] args) {
LOGGER.info("{'provinceCode': null, 'channelSubCode': null, 'platFormCode': '002', 'optCode': null, 'startTimeLong': 1384599600000, 'processTime_sum': 10081,'count': 404, 'suc_count': 0,'suc_rate': '0.00000'}");
}