SSH web登录 出错请帮助看看问题

Question

执行时网页报错：
java.lang.NullPointerException
com.action.LoginAction.login(LoginAction.java:39)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)
org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)

Answer 1

public String login(){
        System.out.println("login");
        System.out.println("username:" + username);
        System.out.println("password:" + password);
        boolean flag = this.loginservice.login(username, password);//调用数据库查询方法，验证用户名、密码
        if(flag){
            return "Success";
        }else{
            return "input";
        }
    }
在这个方法加个断点，跟进去看看哪个对象是空的。

Answer 2

boolean flag = this.loginservice.login(username, password);这里出错上面的可以输出
login
username:123
password:123

Answer 3

让你断点跟到
boolean flag = this.loginservice.login(username, password);//调用数据库查询方法，验证用户名、密码
句，看看有对象是空的不。
如果不是空的，步入这个方法，继续看有哪些对象是空了。

Answer 4

是不是这个意思？
<!-- Action注入 service  id="" 注入 class="action路径" name="loginservice"与LoginAction中声明的要保持一致 -->请问具体要怎么处理？？

Answer 5

好像你这个注入法有问题呀！  <!--  DAO注入sessionFactory -->
    <bean id="logind" class="com.persistence.LoginDAOImpl">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>
     <bean id="logins" class="com.service.LoginServiceImpl" >
       <property name="logindao" ref="logind"/>
   </bean>
   <bean id="com.action.LoginAction" class="com.action.LoginAction" scope="prototype">
       <property name="loginservice" ref="logins"/>
   </bean>

Answer 6

好像你这个注入法有问题呀！  <!--  DAO注入sessionFactory -->
    <bean id="logind" class="com.persistence.LoginDAOImpl">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>
     <bean id="logins" class="com.service.LoginServiceImpl" >
       <property name="logindao" ref="logind"/>
   </bean>
   <bean id="com.action.LoginAction" class="com.action.LoginAction" scope="prototype">
       <property name="loginservice" ref="logins"/>
   </bean>
根本就是乱写的，没有搞清楚注入的用法。

Answer 7

com.action.LoginAction  因为名字与类名一样，有可能struts 的factory没有启用spring  factory，而是用的自己的factory，所以没注入

Answer 8

<!-- 指定由spring负责action对象的创建 -->
<constant name="struts.objectFactory" value="spring" />

Answer 9

就是这个。
提示的很明显了，service 实例为 null 值。

Answer 10

请问怎么解决这个问题呀。这明显就是个注入问题。  <!--  DAO注入sessionFactory -->
    <bean  class="com.persistence.LoginDAOImpl">
        <property name="logind" ref="sessionFactory"/>
    </bean>
     <bean  class="com.service.LoginServiceImpl" >
       <property name="loginservice" ref="logind"/>
   </bean>
   <bean  class="com.action.LoginAction" scope="prototype">
       <property name="loginAction" ref="loginservice"/>
   </bean>
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
    <package name="default" extends="struts-default" namespace="/">
        <action name="Login" class="loginAction" method="login">
            <result name="input">/login.jsp</result>
            <result name="Success">/index.jsp</result>
        </action>
    </package>   
</struts>   

Answer 11

请问怎么解决这个问题呀。这明显就是个注入问题。  <!--  DAO注入sessionFactory -->
    <bean  class="com.persistence.LoginDAOImpl">
        <property name="logind" ref="sessionFactory"/>
    </bean>
     <bean  class="com.service.LoginServiceImpl" >
       <property name="loginservice" ref="logind"/>
   </bean>
   <bean  class="com.action.LoginAction" scope="prototype">
       <property name="loginAction" ref="loginservice"/>
   </bean>
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
    <package name="default" extends="struts-default" namespace="/">
        <action name="Login" class="loginAction" method="login">
            <result name="input">/login.jsp</result>
            <result name="Success">/index.jsp</result>
        </action>
    </package>   
</struts>   <!--  DAO注入sessionFactory -->
<bean id="logind" class="com.persistence.LoginDAOImpl">
<!-- 注入持久化操作所需的SessionFactory -->
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
 <!--service注入dao id为下面的ref  class为 service实现类 name="service实现类中声明的dao"-->
 <bean id="logins" class="com.service.LoginServiceImpl" >
       <property name="logindao" ref="logind"/>
   </bean>
   <!-- Action注入 service  id="" 注入 class="action路径" name="loginservice"与LoginAction中声明的要保持一致 ref随便取-->
   <bean id="com.action.LoginAction" class="com.action.LoginAction" scope="prototype">
       <property name="loginservice" ref="logins"/>
   </bean>
换成
 <!--  DAO注入sessionFactory -->
    <bean  class="com.persistence.LoginDAOImpl">
        <property name="logind" ref="sessionFactory"/>
    </bean>
     <bean  class="com.service.LoginServiceImpl" >
       <property name="loginservice" ref="logind"/>
   </bean>
   <bean  class="com.action.LoginAction" scope="prototype">
       <property name="loginAction" ref="loginservice"/>
   </bean>
出错呀，还是别的什么意思？

Answer 12

<!-- 指定由spring负责action对象的创建 -->
<constant name="struts.objectFactory" value="spring" />
这个struts都不加上，spring等于没用一样，。。

Answer 13

我没有用过id注入，但是看你的代码：
LoginServiceImpl ：中
  private LoginDAO logindao;
    public void setLogindao(LoginDAOImpl login) {
        this.logindao = login;
    }
与
LoginAction ：中
public void setLoginservice(LoginService loginservice) {
        this.loginservice = loginservice;
    }
明显不同！

Answer 14

竟然是ssh项目，那么action实例应该也是用spring容器创建，你容器那里的bean一团糟。你现在解决没，如果还没解决，我起来发我做的给你看下，我也是初学者。可以交流交流

Answer 15

看了下，貌似没什么问题。
把这里面的   <bean id="com.action.LoginAction" class="com.action.LoginAction" scope="prototype">
       <property name="loginservice" ref="logins"/>
   </bean> com.action.LoginAction这个换成loginA，<package name="default" extends="struts-default" namespace="/">
        <action name="Login" class="com.action.LoginAction" method="login">
            <result name="input">/login.jsp</result>
            <result name="Success">/index.jsp</result>
        </action>
    </package>   这里面的com.action.LoginAction 换成对应的loginA