spring配置数据源读取properties，properties文件中参数名jdbc.*正常，不带jdbc.出现异常_spring jdbc.properties 为什么必须是jdbc.driver-优快云博客

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在尝试通过Spring配置数据源时，遇到一个问题：当properties文件中的参数不以jdbc.*开头时，程序出现异常。但将参数名改为jdbc.*后，配合更新的applicationContext.xml，程序运行正常。即使不使用properties文件，直接硬编码配置也能正常工作。目前尚不清楚具体原因，期待专家解答。

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通过spring获取数据库连接

  @Test
    public void test2() throws PropertyVetoException, SQLException {
        ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
        DataSource dataSource =  app.getBean(DataSource.class);
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }

配置文件不带(jdbc.*)

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/db3
username=root
password=123

applicationContext.xml内容：

  <!--配置数据源-->
    <context:property-placeholder location="classpath:jdbc.properties"/>
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${driver}"></property>
        <property name="jdbcUrl" value="${url}"></property>
        <property name="user" value="${username}"></property>
        <property name="password" value="${password}"></property>
    </bean>

出现异常：

警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@5d09c874 -- 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: Access denied for user 'root' (using password: YES)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:910)
	at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:3923)
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1273)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2031)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:718)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
	at sun.reflect.GeneratedConstructorAccessor12.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	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)

............

更改参数名为jdbc.*

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/db3
jdbc.username=root
jdbc.password=12

相应的applicationContext.xml做处理

  <!--配置数据源-->
    <context:property-placeholder location="classpath:jdbc.properties"/>
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${jdbc.driver}"></property>
        <property name="jdbcUrl" value="${jdbc.url}"></property>
        <property name="user" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
    </bean>

运行正常

com.mchange.v2.c3p0.impl.NewProxyConnection@6f3187b0

不通过properties文件，直接写死也能正常运行。
不知道哪里出了问题，希望大佬能帮忙讲解。