SpringMVC 无法获取连接报错

在进行单元测试的时候，发现报错 Could not get JDBC Connection; nested exception is java.sql.SQLException: 

jdbc.properties配置文件信息

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/seckill?useUnicode=true&characterEncoding=utf-8
username=root
password=123456

Spring-dao.xml  部分配置信息

运行报错：

Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!
	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:122)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:113)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:73)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:386)
	... 39 more
Caused by: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
	at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:82)
	at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:68)
	at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:315)
	at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:75)
	at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:61)
	at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:303)
	at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:154)
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:102)
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:82)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:120)
	... 46 more
Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
	at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)
	at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
	at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
	... 56 more
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
	at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
	at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
	at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
	... 59 more

仔细检查了均没有发现异常，后来将 Spring-dao.xml  部分配置信息进行修改

 
        
        
            
            
            
            root"/>
            

            
            
            
            
            
            
            
            
            
        

发现修改user的信息直接为数据库的用户名，就OK。于是将${username}配置到drivaerClass的后面（junit4不会打印出数据库用户名密码），发现居然${username}的值变成了Administrator

呵呵啦。。。。发现问题，将所有的配置前面加上前缀jdbc.username这种形式即可，引用也要修改即可。