[英]service variable is null when accessing from main class
我有一個名為App.java的swing類,在其中有以下內容:
private EmployeeService employeeService;
public void setEmployeeService(EmployeeService employeeService) {
this.employeeService = employeeService;
}
在我的applicationContext.xml中,我有以下內容:
<bean id="employeeDao" class="com.myapp.dao.EmployeeDaoImpl">
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="employeeService" class="com.myapp.service.EmployeeServiceImpl">
<property name="employeeDao" ref="employeeDao" />
</bean>
<bean id="app" class="com.myapp.swing.App">
<property name="employeeService" ref="employeeService" />
</bean>
當我運行App.java時,我收到employeeService為null的錯誤。 為什么會這樣? 如果我直接從類中分配employeeService bean:
ConfigurableApplicationContext context = new ClassPathXmlApplicationContext("/spring/applicationContext.xml");
EmployeeService employeeService = (EmployeeService) context.getBean("employeeService");
employeeService.validateEmployeeNo(1234);
context.close();
...
我能夠成功運行它。 當我從applicationContext.xml注入時,不是在App.java中彈簧連接employeeService嗎?
除非您的App類是由Spring容器創建的,否則您嘗試訪問的任何服務都將為null。 您如何初始化您的App類?
App myApp = new App();
要么
App myApp = (App) context.getBean("app");
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