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Ich habe einen schwierigen Suchfehler in meinem Projekt. Es kann keine Daten in die Datenbank einfügen.HTTP Status 500 - Anforderungsverarbeitung fehlgeschlagen NullException
mein Controller:
package com.recome.controller;
import com.recome.dao.UserDAO;
import com.recome.model.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
@Controller
public class RegisterController {
private UserDAO userDAO;
@RequestMapping(value = "/ShowRegisterForm", method = RequestMethod.GET)
public ModelAndView newContact(ModelAndView model) {
User newUser = new User();
model.addObject("User", newUser);
model.setViewName("registerForm");
return model;
}
@RequestMapping(value = "/saveUser", method = RequestMethod.POST)
public ModelAndView saveUser(@ModelAttribute User user) {
userDAO.create(user); **//the error point**
return new ModelAndView("redirect:index.jsp");
}
}
Dispatcher-Servlet:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/recome"/>
<property name="username" value="root"/>
<property name="password" value=""/>
</bean>
<bean id="UserDAOImpl" class="com.recome.dao.UserDAOImpl">
<property name="dataSource" ref="dataSource" />
</bean>
<context:component-scan base-package="com.recome.controller" />
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/views/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
</beans>
Benutzeroberfläche:
package com.recome.dao;
import com.recome.model.User;
import java.util.List;
import javax.sql.DataSource;
public interface UserDAO {
public void setDataSource(DataSource ds);
public void create(User user);
public void update(String email,String password,String fullname,Integer id);
public User get(Integer id);
public void delete(Integer id);
public List<User> list();
}
Benutzer Umsetzung:
package com.recome.dao;
import com.recome.model.User;
import java.util.List;
import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
public class UserDAOImpl implements UserDAO{
private JdbcTemplate jdbcTemplate;
private DataSource dataSource;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
this.jdbcTemplate = new JdbcTemplate(dataSource);
}
public void create(User user) {
String query = "insert into user(email,password,fullname) "
+ "values(?,?,?)";
jdbcTemplate.update(query,user.getEmail(),user.getPassword(),user.getFullname());
}
public void update(String email, String password, String fullname, Integer id) {
String query = "update user set email = ?"+",password = ?"+",fullname = ? where id = ?";
jdbcTemplate.update(query,email,password,fullname,id);
}
public User get(Integer id) {
return null;
}
public void delete(Integer id) {
String query = "delete from user where id = ?";
jdbcTemplate.update(query,id);
}
public List<User> list() {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
}
Fehler:
org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [dispatcher] in context with path [/Recome] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at com.recome.controller.RegisterController.saveUser(RegisterController.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:175)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:446)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:434)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2500)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2489)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
kann mir jemand helfen. Ich suche bereits nach ähnlichen Problemen, bekomme aber immer noch nicht den Fehler.
Offensichtlich ist 'userDAO' null. – shmosel
Mögliches Duplikat von [Was ist eine Nullzeiger-Ausnahme und wie behebe ich sie?] (Http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do -i-fix-it) –