今天在进行spring与postgresql的连接时发现了一个错误，错误信息如下：
Exception in thread "main" java.sql.SQLException: Cannot create PoolableConnectionFactory (FATAL: password authentication failed for user "Rick")
at org.apache.commons.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2152)
at org.apache.commons.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:1903)
at org.apache.commons.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1413)
at cn.yourside.community.web.test.BeanTest.main(BeanTest.java:16)
Caused by: org.postgresql.util.PSQLException: FATAL: password authentication failed for user "Rick"
at org.postgresql.core.v3.ConnectionFactoryImpl.doAuthentication(ConnectionFactoryImpl.java:408)
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:181)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:64)
at org.postgresql.jdbc2.AbstractJdbc2Connection.<init>(AbstractJdbc2Connection.java:144)
at org.postgresql.jdbc3.AbstractJdbc3Connection.<init>(AbstractJdbc3Connection.java:29)
at org.postgresql.jdbc3g.AbstractJdbc3gConnection.<init>(AbstractJdbc3gConnection.java:21)
at org.postgresql.jdbc4.AbstractJdbc4Connection.<init>(AbstractJdbc4Connection.java:31)
at org.postgresql.jdbc4.Jdbc4Connection.<init>(Jdbc4Connection.java:24)
at org.postgresql.Driver.makeConnection(Driver.java:410)
at org.postgresql.Driver.connect(Driver.java:280)
at org.apache.commons.dbcp2.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:39)
at org.apache.commons.dbcp2.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:205)
at org.apache.commons.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:2162)
at org.apache.commons.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2148)
... 3 more
其中Rick是我的PC的用户名，感觉很奇怪，为什么我配置的用户名明明是postgres，在这里却变成了Rick。我修改配置文件件连接mysql数据库，发现报如下错误信息：
Exception in thread "main" java.sql.SQLException: Cannot create PoolableConnectionFactory (Access denied for user'Rick'@'localhost' (using password: YES))
at org.apache.commons.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2152)
at org.apache.commons.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:1903)
at org.apache.commons.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1413)
at cn.yourside.community.web.test.BeanTest.main(BeanTest.java:16)
Caused by: java.sql.SQLException: Access denied for user 'Rick'@'localhost' (using password: YES)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1084)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4232)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4164)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:926)
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1748)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1288)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2506)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2539)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2321)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:832)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
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:409)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:417)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
at org.apache.commons.dbcp2.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:39)
at org.apache.commons.dbcp2.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:205)
at org.apache.commons.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:2162)
at org.apache.commons.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2148)
... 3 more
看完之后突然想起来之前好像犯过这个错误，仔细一想，之前是因为在一个类里面存在两个username，觉得是username重复被覆盖造成的，所以我将username换成databaseUserName，替换之后就成功了，这个问题貌似和spring有关系，在它的默认的applicationContext中有username的默认值，与自定义的值造成混淆。