Я пытаюсь создать базовые данные выбора в mysql в Struts2 в eclipse. Я получаю исключения, которые не могу разрешить, исключение возникло во время обработки запроса: null, мой одноклассник сказал мне, что я, вероятно, пишу неправильные распорки, но распорки моей находки копируют insertStudentGrade и Insert не ошибаются, я понятия не имею ...
struts.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<package name="struts2" namespace="/" extends="struts-default">
<action name="login" class="com.Action.LoginAction">
<result name="error">/error.jsp</result>
<result name="success">/success.jsp</result>
</action>
<action name="save" class="com.Action.AddStudentGrade" method="insert">
<result name="success">/success.jsp</result>
<result name="error">/error.jsp</result>
</action>
<action name="find" class="com.Action.FindStudentGrade" method="find">
<result name="success">/success.jsp</result>
<result name="error">/error.jsp</result>
</action>
</package>
<include file="example.xml"/>
<!-- Add packages here -->
</struts>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_9" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>Struts Blank</display-name>
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
</web-app>
подробности проблемы
08:49:40.900 [http-nio-8080-exec-3] ERROR org.apache.struts2.dispatcher.DefaultDispatcherErrorHandler - Exception occurred during processing request: null
java.lang.NullPointerException
at com.Action.FindStudentGrade.find(FindStudentGrade.java:28) ~[classes/:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_192]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_192]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_192]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_192]
at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:897) ~[ognl-3.0.21.jar:?]
at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1299) ~[ognl-3.0.21.jar:?]
at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68) ~[ognl-3.0.21.jar:?]
at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108) ~[xwork-core-2.3.36.jar:2.3.36]
at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1375) ~[ognl-3.0.21.jar:?]
at ognl.ASTMethod.getValueBody(ASTMethod.java:91) ~[ognl-3.0.21.jar:?]
at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212) ~[ognl-3.0.21.jar:?]
at ognl.SimpleNode.getValue(SimpleNode.java:258) ~[ognl-3.0.21.jar:?]
at ognl.Ognl.getValue(Ognl.java:470) ~[ognl-3.0.21.jar:?]
at ognl.Ognl.getValue(Ognl.java:434) ~[ognl-3.0.21.jar:?]
at com.opensymphony.xwork2.ognl.OgnlUtil$3.execute(OgnlUtil.java:398) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecuteMethod(OgnlUtil.java:450) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.ognl.OgnlUtil.callMethod(OgnlUtil.java:396) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:430) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:290) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:251) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41) ~[struts2-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) ~[struts2-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:168) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76) ~[struts2-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73) ~[struts2-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125) ~[struts2-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91) ~[struts2-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253) ~[struts2-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:140) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) ~[struts2-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189) ~[xwork-core-2.3.36.jar:2.3.36]
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245) ~[xwork-core-2.3.36.jar:2.3.36]
at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) ~[struts2-core-2.3.36.jar:2.3.36]
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:575) [struts2-core-2.3.36.jar:2.3.36]
at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81) [struts2-core-2.3.36.jar:2.3.36]
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99) [struts2-core-2.3.36.jar:2.3.36]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.53]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.53]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) [catalina.jar:8.0.53]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94) [catalina.jar:8.0.53]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:492) [catalina.jar:8.0.53]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) [catalina.jar:8.0.53]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [catalina.jar:8.0.53]
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620) [catalina.jar:8.0.53]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) [catalina.jar:8.0.53]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:502) [catalina.jar:8.0.53]
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1152) [tomcat-coyote.jar:8.0.53]
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684) [tomcat-coyote.jar:8.0.53]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1539) [tomcat-coyote.jar:8.0.53]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1495) [tomcat-coyote.jar:8.0.53]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_192]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_192]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util.jar:8.0.53]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_192]
selectStudentGrade
package com.Action;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.opensymphony.xwork2.ActionSupport;
import com.util.DBUtil;
public class FindStudentGrade extends ActionSupport{
/**
*
*/
private static final long serialVersionUID = 1L;
private String stu_id="1";
public String find() throws SQLException{
String sql="SELECT stu_id,stu_name,stu_math,stu_chinese,stu_english FROM stu_grade where id='"+stu_id+"'";
DBUtil dbUtil=new DBUtil();
ResultSet rSet=dbUtil.executeQuery(sql);
String id=null;
String name=null;
String math=null;
String chinese=null;
String english=null;
while(rSet.next()){
System.out.println("zxzx");//a test,but can not print in console
id=rSet.getString("stu_id");
name=rSet.getString("stu_name");
math=rSet.getString("stu_math");
chinese=rSet.getString("stu_chinese");
english=rSet.getString("stu_english");
}
System.out.println(id+name+math+chinese+english);
return "success";
}
}