SpringMVC线程池问题

Question

大家好我又来问问题了。。。

事情是这样的。

现在的项目使用了Hessian。

在Commander 项目中调用 Spider 项目中的一个service

这个Service中使用了线程池。

然而问题来了。当在Spider项目中自己调用自己的Service的时候，一切正常。

但是通过Hessian调用Spider的Service的时候，线程池却是空指针的。

代码如下：
这是Spider（被调用）项目中的配置：

<?xml version="1.0" encoding="UTF-8"?>

<!-- 业务类 -->  
<beans xmlns="http://www.springframework.org/schema/beans"  
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
    xmlns:aop="http://www.springframework.org/schema/aop"  
    xmlns:tx="http://www.springframework.org/schema/tx"  
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd  
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd  
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"  
    default-autowire="byName">    

<bean id="impl" class="com.whr.Service.Impl.WorkServiceImpl" />      
<!-- 远程服务 -->  
<bean name="/workService" class="org.springframework.remoting.caucho.HessianServiceExporter">  
     
    <property name="service" ref="impl" />  
    <property name="serviceInterface">  
        <value>
            com.whr.Service.WorkService
        </value>  
    </property>
</bean> 
</beans>

这是Spider（被调用）项目中的Service 实现：

package com.whr.Service.Impl;

import java.sql.Date;
import java.util.List;

import javax.annotation.Resource;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.select.Elements;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.task.TaskExecutor;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.whr.Dao.WorkDao;
import com.whr.Entity.Work;
import com.whr.Service.WorkService;
import com.whr.Spiders.Spider_ZhiLian;

@Service("workService")
public class WorkServiceImpl implements WorkService {

    @Autowired
    private WorkDao workDao;
    @Resource(name = "taskExecutor_Spider") 
    private TaskExecutor taskExecutor;// 线程池
    
    @Autowired
    private Spider_ZhiLian spider_ZhiLian;
    
    public List<Work> getAllWork() {
        return workDao.getAllWork();
        
    }

    
    public void saveWork()
    {
        System.out.println("Commander 调用  Spider");
        TaskExecutor teExecutor = this.taskExecutor;
        teExecutor.execute(new Spider_ZhiLian(workDao));
    }


    public void updateWork(Work work) 
    {
        workDao.updateWork(work);
    }


    public void deleteWork(Work work) 
    {
        workDao.deleteWork(work);
    }
}

结果：

Commander 调用  Spider
2016-04-13 10:15:49 [org.springframework.remoting.support.RemoteInvocationTraceInterceptor]-[WARN] Processing of HessianServiceExporter remote call resulted in fatal exception: com.whr.Service.WorkService.saveWork
java.lang.NullPointerException
    at com.whr.Service.Impl.WorkServiceImpl.saveWork(WorkServiceImpl.java:42)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.remoting.support.RemoteInvocationTraceInterceptor.invoke(RemoteInvocationTraceInterceptor.java:78)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
    at $Proxy38.saveWork(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.caucho.hessian.server.HessianSkeleton.invoke(HessianSkeleton.java:306)
    at com.caucho.hessian.server.HessianSkeleton.invoke(HessianSkeleton.java:221)
    at org.springframework.remoting.caucho.HessianExporter.doInvoke(HessianExporter.java:223)
    at org.springframework.remoting.caucho.HessianExporter.invoke(HessianExporter.java:138)
    at org.springframework.remoting.caucho.HessianServiceExporter.handleRequest(HessianServiceExporter.java:66)
    at org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter.handle(HttpRequestHandlerAdapter.java:51)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.orm.hibernate4.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:151)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1852)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

Commander调用的过程（部分）：

public class UserController {

    @Autowired
    private UserService userService;
    @Autowired
    private WorkService workService;
    @Autowired
    private HessianService testHessianService;
    
    private static Logger logger = Logger.getLogger(UserController.class);
    
    @RequestMapping("/test")
    public ModelAndView getStudent(HttpServletRequest request,HttpServletResponse response,ModelMap modelMap) throws MalformedURLException
    {
        
        /*HessianModel model = testHessianService.getHessianModel("uid", "pwd");   
        logger.info("username: " + model.getUsername());*/
        testHessianService.saveWork();
        
        
        List<User> list = userService.getAllUser();
        modelMap.put("students", list);
        logger.info("Log4测试");
        return new ModelAndView("test", modelMap); 
    }

调用方的Spring配置：

<bean id="testHessianService" class="org.springframework.remoting.caucho.HessianProxyFactoryBean">  
        <property name="serviceUrl" value="http://localhost:8080/Spider/hessian/workService"/>  
        <property name="serviceInterface" value="com.whr.Hessian.HessianService"/>  
    </bean>

调用方的Hessian接口：

package com.whr.Hessian;

public interface HessianService {
    public String sayHello(String username);  
    public void saveWork();
    public HessianModel getHessianModel(String username, String password);
}

以上。

问题简述就是一个在本项目中可以调用的Service经过Hessian调用后线程池缺空指针了。但是明确可以调用到的。

求大神解答。谢谢！

刚才尝试了一下不使用线程池，通过Hessian调用服务然后在服务中直接操作Dao层，也是不好使的，一样的空指针。
但是在服务端自己调用服务端的Service却好使。
貌似Hessian调用的时候所有的注入都失效了。。。

Answer 1

首先，非常感谢 @Kavlez 给予的帮助，提示了我查找是不是注解配置的问题。

这个问题查了查资料分析了一下，虽然解决了但是原理不甚清楚。还望高手指点。以下是修改后的Hessian-servlet.xml

<?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:jee="http://www.springframework.org/schema/jee"  
    xmlns:tx="http://www.springframework.org/schema/tx"   
    xmlns:context="http://www.springframework.org/schema/context"  
    xmlns:aop="http://www.springframework.org/schema/aop"  
    xmlns:p="http://www.springframework.org/schema/p"  
    xsi:schemaLocation="http://www.springframework.org/schema/beans  
     http://www.springframework.org/schema/beans/spring-beans-3.0.xsd  
     http://www.springframework.org/schema/tx  
     http://www.springframework.org/schema/tx/spring-tx-3.0.xsd  
     http://www.springframework.org/schema/jee  
     http://www.springframework.org/schema/jee/spring-jee-3.0.xsd  
     http://www.springframework.org/schema/aop  
     http://www.springframework.org/schema/aop/spring-aop-3.0.xsd  
     http://www.springframework.org/schema/context  
     http://www.springframework.org/schema/context/spring-context-3.0.xsd  
     http://activemq.apache.org/schema/core  
     http://activemq.apache.org/schema/core/activemq-core.xsd"  
    >   
      
    <context:annotation-config />  
    <!-- 组件扫描,使用annotation 自动注册bean,并检查@Required,@Autowired的属性已被注入 -->  
    <context:component-scan base-package="com.whr" />  
      
      <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor" />  
      
    <!-- 异步线程池 -->
    <bean id="taskExecutor_Spider"
        class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
        <!-- 核心线程数 -->
        <property name="corePoolSize" value="10" />
        <!-- 最大线程数 -->
        <property name="maxPoolSize" value="100" />
        <!-- 队列最大长度 >=mainExecutor.maxSize -->
        <property name="queueCapacity" value="1000" />
        <!-- 线程池维护线程所允许的空闲时间 -->
        <property name="keepAliveSeconds" value="300" />
        <!-- 线程池对拒绝任务(无线程可用)的处理策略 -->
        <property name="rejectedExecutionHandler">
            <bean class="java.util.concurrent.ThreadPoolExecutor$CallerRunsPolicy" />
        </property>
    </bean>
      
    <bean name="/workService"    
        class="org.springframework.remoting.caucho.HessianServiceExporter">    
        <!-- service的ref与HelloServiceImpl中@Service中配置的一致 -->    
        <property name="service" ref="workService" />    
        <!-- 接口的路径 -->    
        <property name="serviceInterface"    
            value="com.whr.Service.WorkService" />    
    </bean>    
</beans>

还有一个细节就是在Service上要如下书写：

@Service("workService")

写成这样就不可以：

@Service

但是在其他的地方又两种都可以。这也是一个不是很理解的地方。

至于修改的点，在于加入了<context:annotation-config /> 配置。
因为之后又试验了各种注解方式注入的bean均不可用，就说明是注解注入方式出现了问题。

查了一些资料看到有人加入了这个配置，试验了一下可以。
然后又根据提示加入了其他的配置，最终的结果就是如上了。

以上。
再次感谢给予帮助的小伙伴。

Answer 2

我无法确定我的方法是否奏效，但题主不妨一试：

WorkServiceImpl中的
@Service("workService")改为@Service

服务端的配置改为：

<bean name="/workService" class="org.springframework.remoting.caucho.HessianServiceExporter">  
     
    <property name="service" ref="workServiceImpl" />  
    <property name="serviceInterface">  
        <value>
            com.whr.Service.WorkService
        </value>  
    </property>
</bean>     

Answer 3

@Service默认是生成bean的id为默认类名首字母小写，也就是workServiceImpl，但是你ref的是workService所以必须写@Service("workService")来指定生成bean的id