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spring 初始化 在action中调用去出现java.lang.NullPointerException错误

0
悬赏园豆:15 [已解决问题] 解决于 2013-04-09 10:19

web.xml

 

<listener>
<listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
</listener>

<!--监听器 用于初始化spring框架-->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!--上下文参数用于log4j以及spring中使用-->
<context-param>
<param-name>webAppRootKey</param-name>
<param-value>/WEB-INF/log4j.properties</param-value>
</context-param>

<!--应用程序上下文参数,指定spring配置文件位置-->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:bean.xml</param-value>
</context-param>

 

 

struts。xml

<struts>
<constant name="struts.devMode" value="true" />
<package name="default" namespace="/" extends="struts-default">
<action name="adduser" class="com.jsw.struts2.action.UserAction">
<result name="success">
/index.jsp
</result>
</action>
</package>

</struts>

 

UserAction.java

public class UserAction extends ActionSupport {

public String name;
public String pass;
public UserService userservice;

public UserService getUserservice() {
return userservice;
}

public void setUserservice(UserService userservice) {
this.userservice = userservice;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getPass() {
return pass;
}

public void setPass(String pass) {
this.pass = pass;
}



public String execute()
{
this.adduser();

return "success";

}

public void adduser()
{
userservice.adduser();

}

 

UserService.java

 

public class UserService {

private UserDAO userdao;


public UserDAO getUserdao() {
return userdao;
}

public void setUserdao(UserDAO userdao) {
this.userdao = userdao;
}

public void adduser()
{

System.out.println("111");
}

}

 

bean.xml

 

<bean id="UserDAO" class="com.jsw.hibernate.dao.UserDAO">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>

<bean id="UserService" class="com.jsw.hibernate.service.UserService">
<property name="userdao" ref="UserDAO"/>
</bean>

<bean id="LoginAction" class="com.jsw.struts2.action.LoginAction">
<property name="userservice" ref="UserService"/>
</bean>

<bean id="UserAction" class="com.jsw.struts2.action.UserAction">
<property name="userservice" ref="UserService"/>
</bean>

 

 

结果在UserAction。java执行userservice.adduser();时出错。

Stacktraces

java.lang.NullPointerException
    com.jsw.struts2.action.UserAction.adduser(UserAction.java:59)
    com.jsw.struts2.action.UserAction.execute(UserAction.java:45)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    java.lang.reflect.Method.invoke(Unknown Source)
    com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:452)
    com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:291)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:254)
    com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:263)
    org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:270)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:190)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
    org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
    org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:498)
    org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
    org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
    org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:859)
    org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:579)
    org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1555)
    java.lang.Thread.run(Unknown Source)
忧愁的主页 忧愁 | 初学一级 | 园豆:2
提问于:2013-04-08 17:00
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最佳答案
0

楼主struts.xml ,中实例化了action ,<action name="adduser" class="com.jsw.struts2.action.UserAction">  

而在spring 中也实例了action,这样实例化对象无法setter ,出现null ,

<bean id="UserAction" class="com.jsw.struts2.action.UserAction">
<property name="userservice" ref="UserService"/>
</bean>

楼主不妨修改为 

struts.xml 

<action name="adduser" class="这里就是spring 注册的action bean 的id">

eg:<action name="adduser" class="UserAction">

 

spring.xml 

<bean id="UserAction" class="com.jsw.struts2.action.UserAction" scope="prototype">
  <property name="userservice" ref="UserService"/>
</bean>

 

 

收获园豆:15
Beyond-bit | 老鸟四级 |园豆:2824 | 2013-04-08 17:34
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