Could not resolve placeholder 'jdbc.driver' in value "${jdbc.driver}"

Question

代码

<beans xmlns="

Not Found! http://www.springframework.org/schema/beans%22

xmlns:xsi="

http://www.w3.org/2001/XMLSchema-instance%22

xmlns:context="

Not Found! http://www.springframework.org/schema/context%22

   xsi:schemaLocation="
    http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd">

<context:property-placeholder location="classpath:database.properties"/>

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <property name="driverClass" value="${jdbc.driver}"/>
    <property name="jdbcUrl" value="${jdbc.url}"/>
    <property name="user" value="${jdbc.username}"/>
    <property name="password" value="${jdbc.password}"/>
</bean>

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" value="dataSource"/>
    <!--   绑定mybatis的配置文件     -->
    <property name="configLocation" value="mybatis-config.xml"/>
</bean>
<!-- 4.配置dao接口扫描包，动态实现了Dao接口可以注入到Spring容器中！   -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>

    <property name="basePackage" value="com.kuang.dao"/>
</bean>

问题：at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:221)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'jdbc.driver' in value "${jdbc.driver}"

Answer 1

为什么不使用阿里的连接池？另外你的连接配置是不是有问题，前面需要加jdbc.吗？你的database.properties里面的key难道是类似jdbc.driver吗？如果key是类似driver=xxx的，配置文件里的变量就不是jdbc.driver而是driver

Answer 2

用阿里的连接池也是同样的问题，database.properties里面的key 是driver=xxx，但是去掉了jdbc以后还是出现错误：Cannot convert value of type 'java.lang.String' to required type 'javax.sql.DataSource' for property 'dataSource': no matching editors or conversion strategy found。

Answer 3

你没有发现吗，报错信息不一样了，接下来就是

<property name="dataSource" value="dataSource">
配置错了，这写法Spring会以字符串方式注入，报类型不匹配异常,改为
<property name="dataSource" ref="dataSource"/>

Answer 4

嗯，我这个我已经发现了修改了，但是又出现了了另外的问题：Caused by: org.apache.ibatis.exceptions.PersistenceException:

Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!

The error may exist in com/kuang/dao/bookMapper.xml

The error may involve com.kuang.dao.bookMapper.queryAllBook

The error occurred while executing a query

Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain 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:149)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:140)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:426)
... 33 more

要上手太难了