從XML屬性文件加載和注入屬性Bean與彈簧

Question

我想從XML屬性文件加載SQL查詢並將它作爲java.util.Property注入到我的DAO類中。這個SQLs.xml駐留在與應用程序上下文相同的目錄下（我使用Maven結構，所以它們都在src/main/resources下）。我的應用程序上下文文件看起來像如下：

<beans xmlns="http://www.springframework.org/schema/beans" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" 
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" 
xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx" 
xmlns:task="http://www.springframework.org/schema/task" 
xmlns:util="http://www.springframework.org/schema/util" 
xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd"> 

<bean id="EmployeeDAO" class="pkg.dao.EmployeeDAOImpl"> 
    <property name="dataSource" ref="dataSource" /> 
</bean> 

<bean id="dataSource" 
    class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 

    <property name="driverClassName" value="oracle.jdbc.OracleDriver" /> 
    <property name="url" value="oracle jdbc url" /> 
    <property name="username" value="username" /> 
    <property name="password" value="password" /> 
</bean> 

<util:properties id="queryProps" location="classpath:SQLs.xml"/> 

<bean id="employeeDAOProp" class="pkg.dao.EmployeeDAOImpl"> 
    <property name="queryProps" ref="queryProps" /> 
</bean> 

而且SQLs.xml內容是：

<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd"> 

<properties> 

    <entry key="getEmployee"> 
     select * from employee; 
    </entry> 

</properties> 

的DAO類：

public class EmployeeDAO { 

    private DataSource dataSource; 
    private Properties queryProps; 

    public Properties getQueryProps() { 
    return queryProps; 
    } 

    public void setQueryProps(Properties queryProps) { 
    this.queryProps = queryProps; 
    } 

    public void setDataSource(DataSource dataSource) { 
    this.dataSource = dataSource; 
    } 

    public Employee getEmployee(int id) { 
    String sql = queryProps.getProperty("getEmployee"); 
    } 
} 

我加載上下文主應用程序中的文件爲：

ConfigurableApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); 

我可以加載EmployeeDAO沒有問題，並在其getEmployee()方法調用。即使是datasource也可以毫無問題地提取所有需要的鍵/值。但queryProps始終爲空。

Answer 1

看來我正在將屬性注入兩個不同的實例。

<util:properties id="queryProps" location="classpath:SQLs.xml"/> 
    <bean id="EmployeeDAO" class="pkg.dao.EmployeeDAOImpl"> 
     <property name="dataSource" ref="dataSource" /> 
     <property name="queryProps" ref="queryProps" /> 
    </bean> 

現在queryProps Property包含來自SQLs.xml預期的內容。