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log4j:WARN No appenders could be found for logger (org.apache.ibatis.logging.LogFactory).

log4j:WARN Please initialize the log4j system properly.

log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

org.apache.ibatis.exceptions.PersistenceException: 

### Error querying database.  Cause: java.lang.NullPointerException

### The error may exist in com/bjsxt/mapper/UsersMapper.xml

### The error may involve com.bjsxt.mapper.UsersMapper.selectByPrimaryKey

### The error occurred while executing a query

### Cause: java.lang.NullPointerException

at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)

at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:149)

at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:140)

at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:76)

at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:87)

at org.apache.ibatis.binding.MapperProxy$PlainMethodInvoker.invoke(MapperProxy.java:152)

at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:85)

at com.sun.proxy.$Proxy4.selectByPrimaryKey(Unknown Source)

at com.bjsxt.service.impl.UsersServiceImpl.selectUsersById(UsersServiceImpl.java:17)

at com.bjsxt.test.TestSelect.selectUsersById(TestSelect.java:16)

at com.bjsxt.test.TestSelect.main(TestSelect.java:10)

Caused by: java.lang.NullPointerException

at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:936)

at java.util.concurrent.ConcurrentHashMap.containsKey(ConcurrentHashMap.java:964)

at org.apache.ibatis.datasource.unpooled.UnpooledDataSource.initializeDriver(UnpooledDataSource.java:230)

at org.apache.ibatis.datasource.unpooled.UnpooledDataSource.doGetConnection(UnpooledDataSource.java:223)

at org.apache.ibatis.datasource.unpooled.UnpooledDataSource.doGetConnection(UnpooledDataSource.java:219)

at org.apache.ibatis.datasource.unpooled.UnpooledDataSource.getConnection(UnpooledDataSource.java:95)

at org.apache.ibatis.datasource.pooled.PooledDataSource.popConnection(PooledDataSource.java:432)

at org.apache.ibatis.datasource.pooled.PooledDataSource.getConnection(PooledDataSource.java:89)

at org.apache.ibatis.transaction.jdbc.JdbcTransaction.openConnection(JdbcTransaction.java:139)

at org.apache.ibatis.transaction.jdbc.JdbcTransaction.getConnection(JdbcTransaction.java:61)

at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:337)

at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:86)

at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62)

at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:325)

at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)

at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)

at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:89)

at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147)

... 9 more

null

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