报错日志信息如下：
2015-03-25 09:56:28,893 WARN resourcepool.BasicResourcePool - com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@10987197 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
java.sql.SQLException: null, message from server: "Host '100.0.0.12' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'"
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1096)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2048)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:723)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
at sun.reflect.GeneratedConstructorAccessor6.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)
at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
明显的"Host '100.0.0.12' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'"主机100.0.0.12不能连接数据库，原因是同一个ip在短时间内产生太多（超过mysql数据库max_connection_errors的最大值）中断的数据库连接而导致的阻塞，我的解决办法是：登陆数据库主机，
进入/usr/bin/目录，执行 mysqladmin flush-hosts -h100.0.0.13 -P3306 -uroot -prootpwd;命令，参数分别为：数据库主机IP，数据库端口，root用户名，root用户密码，执行成功，主机100.0.0.12就能够连接数据库了。