本文深入探讨了Struts2与Spring框架整合时，通过struts-spring-plugin实现action注入的原理及常见问题。重点阐述了如何确保action属性与Spring配置文件中的bean名称一致，以实现自动装配。同时，文中通过实例分析了当bean名称不匹配时，导致的异常情况及其解决策略。
对于action的注入 不是spring的配置所能左右的 而是struts-spring-plugin起作用 struts2会去spring配置文件里已有的bean里找和action中的属性名一样的bean 如下：
action:
public class LoginAction extends ActionSupport {
private static final long serialVersionUID = 1L;
//此属性名必须和spring配置文件中的id名一致
CustomersService
customersService;
public CustomersService getCustomersService() {
return customersService;
}
public void setCustomersService(CustomersService customersService) {
this.customersService = customersService;
}
.......
}
spring配置文件:
<!-- 这里的id必须与action中属性名一致-->
<bean id="customersService" class="com.lyq.serviceImpl.CustomersServiceImpl">
<property name="customersDAO">
<ref local="customersDAOImpl" />
</property>
</bean>
<!-- 此bean不用配都行 配了多余 因为不是spring主动注入进action的 而是 struts-spirng-plugin向Spring已有bean中要的 然后自动装进属性里 既然是自动所以索要BEAN名称必须和属性名一致 不然它没办法找到bean 鬼知道咱们起的什么名字
<bean id="loginAction" class="com.lyq.action.LoginAction">
<property name="customersService">
<ref local="customersService" />
</property>
</bean> -->
原来我的bean名称不叫customersService 而是叫customersServiceImpl 结果怎么都装不上 eclipse不报错 网页报错如下：
type Exception report
message
description The server encountered an internal error that prevented it from fulfilling this request.
exception
java.lang.NullPointerException com.lyq.action.LoginAction.execute(LoginAction.java:43) 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:453) com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:292) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:255) org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) 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:249) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) 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:249) com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:90) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) 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:249) com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:192) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:511) org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77) org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
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