问题：jdbc不能连接
org.springframework.jdbc.CannotGetJdbcConnectionException:
如下报错：
Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)
The error may exist in file [E:\Workspaces\eclipse.metadata.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\teacher_information\WEB-INF\classes\com\qhua\mapper\UserMapper.xml]
The error may involve com.qhua.mapper.UserMapper.findById
The error occurred while executing a query
Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)] with root cause
java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3014)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:568)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1014)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2199)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2230)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2025)
at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:778)
at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:294)
at org.apache.commons.dbcp.BasicDataSource.validateConnectionFactory(BasicDataSource.java:1247)
解决办法：
先说报错原因：连接数据库的配置文件有错jdbc.properties。
jdbc.properties错误文件如下
分析：原来是端口号错误
修改：把8080改为3306,就成功了。哎呀，细心决定天下