在業務邏輯中訪問應用程序上下文的實例時發生NullPointerException。如何訪問應用程序上下文的實例？

Question

尋找您寶貴的建議/投入。 下面是實際的xml文件 - ApplicationContext和JobSchedulerServiceContext。

--- applicationContext.xml的

<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" 
"http://www.springframework.org/dtd/spring-beans-2.0.dtd"> 
<beans> 
<bean id="applicationContextImpl" class="com. services.ApplicationContextImpl" scope="singleton"> 
<property name="dataAcquisitionService"> 
<ref bean="dataAcquisitionService" /> 
</property> 
<property name="equipDataAcquisitionService"> 
<ref bean="equipDataAcquisitionService" /> 
</property> 
<property name="emailService"> 
<ref bean="emailService" /> 
</property> 
<property name="externalIoService"> 
<ref bean="externalIoService" /> 
</property> 
<property name="persistenceService"> 
<ref bean="persistenceService" /> 
</property> 
<property name="messageService"> 
<ref bean="messageService" /> 
</property> 
<property name="uiService"> 
<ref bean="uiService" /> 
</property> 
</bean> 

<bean id="controller" class="com.services.ColServiceController" scope="singleton"> 
<property name="applicationContextImpl"> 
<ref bean="applicationContextImpl" /> 
</property> 
<property name="serviceName"> 
<value>Service Controller</value> 
</property> 
<property name="serviceMap"> 
<map> 
<entry key="message"> 
<ref bean="messageService" /> 
</entry> 
<entry key="persistence"> 
<ref bean="persistenceService" /> 
</entry> 
<entry key="email"> 
<ref bean="emailService" /> 
</entry> 
<entry key="dataAcquisition"> 
<ref bean="dataAcquisitionService" /> 
</entry> 
<entry key="equipDataAcquisition"> 
<ref bean="equipDataAcquisitionService" /> 
</entry> 
<entry key="jobScheduler"> 
<ref bean="jobSchedulerService" /> 
</entry> 
<entry key="ui"> 
<ref bean="uiService" /> 
</entry> 
<entry key="externalIo"> 
<ref bean="externalIoService" /> 
</entry> 
</map> 
</property> 
</bean> 
<bean id="applicationContextProvider" class="com.cymer.services.ApplicationContextProvid er"> 
</bean> 
</beans> 

--- JobSchedulerServiceContext.xml

<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" 
"http://www.springframework.org/dtd/spring-beans-2.0.dtd"> 
<beans> 
<bean id="jobSchedulerService" class="com. services.scheduler.JobSchedulerServiceImpl" scope="singleton"> 
<property name="applicationContextImpl"> 
<ref bean="applicationContextImpl" /> 
</property> 
<property name="serviceManual"> 
<value>true</value> 
</property> 
<property name="serviceName"> 
<value>Job Scheduler</value> 
</property> 
<property name="jobSpecifiers"> 
<list> 
<bean id="automatedDataSharingJob" class="com. services.scheduler.JobSpecifier" scope="singleton"> 
<property name="taskName"> 
<value>AutomatedDataSharingJob</value> 
</property> 
<property name="execClass"> 
<bean class="com.services.scheduler.job.AutomatedDataSha ringJob" scope="singleton"> 
<property name="applicationContextImpl"> 
<ref bean="applicationContextImpl" /> 
</property> 
<property name="jobManual"> 
<value>false</value> 
</property> 
</bean> 
</property> 
</bean> 

<bean id="runFullVacuumJob" class="com. services.scheduler.JobSpecifier" scope="singleton"> 
<property name="taskName"> 
<value>RunFullVacuumJob</value> 
</property> 
<property name="execClass"> 
<bean class="com. services.scheduler.job.RunFullVacuumJob" scope="singleton"> 
<property name="applicationContextImpl"> 
<ref bean="applicationContextImpl" /> 
</property> 

</list> 
</property> 
</bean> 

<bean id="dataSharingUtil" class="com.datasharing.util.DataSharingUtil" scope="singleton"> 
</bean> 

</beans> 

這是原始的Java類產品是通過從獲得servlet的控制加載應用程序上下文控制器。我嘗試實現了ApplicationContextAware並獲得當前上下文

package com..services; 

import java.io.File; 
import java.util.HashMap; 
import java.util.Map; 

import org.springframework.beans.BeansException; 
import org.springframework.beans.factory.xml.XmlBeanDefin itionReader; 
import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.ClassPathXmlAp plicationContext; 
import org.springframework.context.support.GenericApplica tionContext; 
import org.springframework.core.io.FileSystemResource; 
import org.springframework.context.ApplicationContextAwar e; 
public class ColServiceController 
extends ColServiceBase 
implements ApplicationContextAware 
{ 
public static final String S_SERVICE_CONTROLLER = "S_Service_Controller"; 
private static String[] appContexts = 
{ 
"applicationContext.xml", 
"dataAcquisitionServiceContext.xml", 
"equipDataAcquisitionServiceContext.xml", 
"emailServiceContext.xml", 
"externalIoServiceContext.xml", 
"jobSchedulerServiceContext.xml", 
"messageServiceContext.xml", 
"persistenceServiceContext.xml", 
"statusDataEventAttributeContext.xml", 
"uiServiceContext.xml", 
}; 
private Map<String,ColService> serviceMap = new HashMap<String,ColService>(); 
public ColServiceController() 
{ 
super(ColServiceController.class); 
} 

private static ApplicationContext appContext; 

public static ApplicationContext getApplicationContext() 
{ 
return appContext; 
} 

public static ApplicationContext loadSpringContext(final String confPath) 
{ 
ApplicationContext context = null; 

// If a discrete conf location has been specified, 
// load the bean definition files from there 
if (!StringUtil.isEmpty(confPath)) 
{ 
System.err.println("Loading context files from: " + confPath); 
final GenericApplicationContext ctx = new GenericApplicationContext(); 
final XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(ctx); 

for (int i=0; i < appContexts.length; i++) 
{ 
final File file = new File(confPath + File.separator + appContexts[i]); 
if (file.isFile()) 
{ 
System.err.println("Loading context file: " + file.getPath()); 
xmlReader.loadBeanDefinitions(new FileSystemResource(file)); 
} 
else 
{ 
System.err.println("Skipping: " + appContexts[i]); 
} 
} 

ctx.refresh(); 
context = (ApplicationContext)ctx; 
} 
// ...otherwise, use the files located in the classpath 
else 
{ 
System.err.println("Loading services from classpath."); 
context = new ClassPathXmlApplicationContext(appContexts); 
} 

return context; 
} 

public void setApplicationContext(ApplicationContext ctx) throws BeansException { 
appContext = ctx; }} 

的實例，但getApplicationContext（）總是返回NULL。一旦我將獲得對上下文的參考，我需要重新安排工作。

我無法弄清楚。任何人都可以看看嗎？

如果遇到此問題，建議我提供解決方案。由於

Answer 1

像

ApplicationContext ctx = new ClassPathXmlApplicationContext(new String[] {"context.xml"}); 

Answer 2

讓你的類實現ApplicationContextAware。您將被強制執行的setter方法中通過ApplicationContext。

更新：

• 使context場非靜態。
• 完全擺脫靜態方法
• 閱讀春季官方文檔 - 使用static方法從來不是一個好的主意與春豆。他們的實例住在彈簧容器內，它們在春天實例化。如果是你誰實例化你的類或調用靜態方法，然後春天不起作用。