我在使用时，出现了问题

[schooljenry]

你好，我在使用时出现了下面的问题。是哪里出问题了？
log4j:ERROR Unexpected exception while initialising MongoDbAppender.
java.lang.NullPointerException
at com.mongodb.WriteConcern.valueOf(WriteConcern.java:399)
at com.focusit.log4jmongo.appender.SimpleMongoDbAppender.initialize(SimpleMongoDbAppender.java:392)
at com.focusit.log4jmongo.appender.SimpleMongoDbAppender.activateOptions(SimpleMongoDbAppender.java:80)
at org.apache.log4j.config.PropertySetter.activate(PropertySetter.java:307)
at org.apache.log4j.config.PropertySetter.setProperties(PropertySetter.java:172)
at org.apache.log4j.config.PropertySetter.setProperties(PropertySetter.java:104)
at org.apache.log4j.PropertyConfigurator.parseAppender(PropertyConfigurator.java:809)
at org.apache.log4j.PropertyConfigurator.parseCategory(PropertyConfigurator.java:735)
at org.apache.log4j.PropertyConfigurator.configureRootCategory(PropertyConfigurator.java:615)
at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:502)
at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:547)
at org.apache.log4j.helpers.OptionConverter.selectAndConfigure(OptionConverter.java:483)
at org.apache.log4j.LogManager.(LogManager.java:127)
at org.slf4j.impl.Log4jLoggerFactory.getLogger(Log4jLoggerFactory.java:73)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:253)

[d0k1]

Hello.
I suppose you didn't set desired mongodb concern in log4j properties.
Please, take a look at example log4j configuration(log4.properties) for this appender.
log4j.appender.MongoDB.writeConcern=UNACKNOWLEDGED

[schooljenry]

Thanks for your reply, I tried your method, and then there was a mistake.
2016-09-07 08:27:59
[INFO]-[Thread: main]-[com.mongodb.diagnostics.logging.SLF4JLogger.info()]: Cluster created with settings {hosts=[192.168.62.15:27017], mode=MULTIPLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}

2016-09-07 08:27:59
[INFO]-[Thread: main]-[com.mongodb.diagnostics.logging.SLF4JLogger.info()]: Adding discovered server 192.168.62.15:27017 to client view of cluster

2016-09-07 08:27:59
[INFO]-[Thread: cluster-ClusterId{value='57cf5f0f8f860f2df042360d', description='null'}-192.168.62.15:27017]-[com.mongodb.diagnostics.logging.SLF4JLogger.info()]: Opened connection [connectionId{localValue:1, serverValue:413}] to 192.168.62.15:27017

2016-09-07 08:27:59
[INFO]-[Thread: cluster-ClusterId{value='57cf5f0f8f860f2df042360d', description='null'}-192.168.62.15:27017]-[com.mongodb.diagnostics.logging.SLF4JLogger.info()]: No server chosen by PrimaryServerSelector from cluster description ClusterDescription{type=UNKNOWN, connectionMode=MULTIPLE, all=[ServerDescription{address=192.168.62.15:27017, type=UNKNOWN, state=CONNECTING}]}. Waiting for 30000 ms before timing out