为什么在spring的xml配置文件中配置class属性的内容时，没有提示
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:task="http://www.springframework.org/schema/task"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://www.springframework.org/schema/task
http://www.springframework.org/schema/task/spring-task-3.1.xsd">
<!-- 引入外部的属性文件 -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!-- 配置c3p0的连接池 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driverClass}"/>
<property name="jdbcUrl" value="${jdbc.url}"/>
<property name="user" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</bean>
<!-- 配置业务层的类 -->
<bean id="accountService" class="cn.muke.spring.demo1.AccountServiceImpl">
<property name="accountDao" ref="accountDao"></property>
</bean>
<!-- 配置Dao的类 -->
<bean id="accountDao" class="cn.muke.spring.demo1.AccountDaoImpl">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- 配置事物管理器 -->
<bean id="" class="org.">
</bean>
</beans>
