spring + hibernateプロジェクトのmysql-databaseからオブジェクトを取得できない？

Question

私はHibernateでマッピングのための2つのクラスを作成しました：

package com.pcd.ahmed.model; 
import java.util.Date; 

import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.Id; 
import javax.persistence.Table; 
import javax.validation.constraints.NotNull; 
import javax.validation.constraints.Past; 
import javax.validation.constraints.Size; 
import org.hibernate.validator.constraints.NotEmpty; 
import org.springframework.format.annotation.DateTimeFormat; 

@Entity 
@Table(name="etudiants") 
public class Etudiant { 
@Id 
@GeneratedValue 
@Size(min=4, max=6) 
private String student_ID; 

@NotEmpty 
@Size(min=4, max=45) 
private String firstname; 

@NotEmpty 
@Size(min=4, max=45) 
private String lastname; 

@NotNull 
@Past 
@DateTimeFormat(pattern="MM/dd/yyyy") 
private Date date_birth; 

@NotEmpty 
@Size(min=3, max=4) 
private String class_ID; 
} 

と

package com.pcd.ahmed.model; 

import java.util.Date; 

import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.Id; 
import javax.persistence.Table; 
import javax.validation.constraints.NotNull; 
import javax.validation.constraints.Past; 
import javax.validation.constraints.Size; 

import org.hibernate.validator.constraints.Email; 
import org.hibernate.validator.constraints.NotEmpty; 
import org.springframework.format.annotation.DateTimeFormat; 

@Entity 
@Table(name="student") 
public class Student { 

@Id 
@GeneratedValue 
private Long id; 

@NotEmpty 
@Size(min=4, max=20) 
private String userName; 

@NotEmpty 
private String firstName; 

@NotEmpty 
private String lastName; 

@NotEmpty 
@Size(min=4, max=8) 
private String password; 
} 

を私はリポジトリを使用してMySQLデータベースのテーブルからオブジェクトを取得しようとすると：

package com.pcd.ahmed.repository; 
import org.springframework.data.jpa.repository.JpaRepository; 
import org.springframework.data.jpa.repository.Query; 
import org.springframework.data.repository.query.Param; 
import org.springframework.stereotype.Repository; 

import com.pcd.ahmed.model.Student; 

@Repository("studentRepository") 
public interface StudentRepository extends JpaRepository<Student, Long> { 

@Query("select s from Student s where s.userName = :userName") 
Student findByUserName(@Param("userName") String userName); 
} 

と

package com.pcd.ahmed.repository; 

import org.springframework.data.jpa.repository.JpaRepository; 
import org.springframework.data.jpa.repository.Query; 
import org.springframework.data.repository.query.Param; 
import org.springframework.stereotype.Repository; 

import com.pcd.ahmed.model.Etudiant; 


@Repository("studentRepository1") 
public interface StudentRepository1 extends JpaRepository<Etudiant, String> { 

@Query("select s from etudiants s where s.student_ID = :student_ID") 
Etudiant findBystudent_ID(@Param("student_ID") String student_ID); 

} 

0123中

エラー：

package com.pcd.ahmed.service; 

import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.stereotype.Service; 
import org.springframework.transaction.annotation.Transactional; 

import com.pcd.ahmed.model.Etudiant; 
import com.pcd.ahmed.model.Student; 
import com.pcd.ahmed.repository.StudentRepository; 
import com.pcd.ahmed.repository.StudentRepository1; 

@Service("studentService") 
public class StudentServiceImpl implements StudentService { 

@Autowired 
private StudentRepository studentRepository; 
private StudentRepository1 studentRepository1; 
@Transactional 
public Student save(Student student) { 
    return studentRepository.save(student); 
} 
public Student profileget(String userName, String password) { 
    Student stud = studentRepository.findByUserName(userName); 

    if(stud != null && stud.getPassword().equals(password) && stud.getroles().equals("Parents")) { 
     return stud; 
    } 
    if(stud != null && stud.getPassword().equals(password) && stud.getroles().equals("Administrateur")) { 
     return stud; 
    } 
    if(stud != null && stud.getPassword().equals(password) && stud.getroles().equals("Enseignant")) { 
     return stud; 
    } 
    if(stud != null && stud.getPassword().equals(password) && stud.getroles().equals("Infirmiere")) { 
     return stud; 
    } 

    return null;   
} 

public Etudiant studentget(String student_ID) { 
    Etudiant etud = studentRepository1.findBystudent_ID(student_ID); 
    return etud; 
} 

public int findByLogin(String userName, String password,Student stud) { 
    stud = studentRepository.findByUserName(userName); 

    if(stud != null && stud.getPassword().equals(password) && stud.getroles().equals("Parents")) { 
     return 1; 
    } 
    if(stud != null && stud.getPassword().equals(password) && stud.getroles().equals("Administrateur")) { 
     return 2; 
    } 
    if(stud != null && stud.getPassword().equals(password) && stud.getroles().equals("Enseignant")) { 
     return 3; 
    } 
    if(stud != null && stud.getPassword().equals(password) && stud.getroles().equals("Infirmiere")) { 
     return 4; 
    } 

    return 0;  
} 

public boolean findByUserName(String userName) { 
    Student stud = studentRepository.findByUserName(userName); 

    if(stud != null) { 
     return true; 
    } 

    return false; 
} 


} 

私はこの関数を呼び出します。

public Etudiant studentget(String student_ID) { 
    Etudiant etud = studentRepository1.findBystudent_ID(student_ID); 
    return etud; 
} 

それは言った：

org.apache.catalina.core.StandardWrapperValve invoke 
SEVERE: Servlet.service() for servlet [studentHibernateServlet] in context with path [/StudentEnrollmentWithSpring] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause 
java.lang.NullPointerException 
    at  com.pcd.ahmed.service.StudentServiceImpl.studentget(StudentServiceImpl.java:42) 
    at com.pcd.ahmed.controller.StudentController.login(StudentController.java:84) 
    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:498) 
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219) 
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132) 
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) 
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745) 
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686) 
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80) 
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925) 
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856) 
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936) 
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:838) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650) 
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731) 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) 
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) 
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) 
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) 
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505) 
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169) 
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) 
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956) 
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) 
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:436) 
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1078) 
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625) 
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316) 
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) 

最初の1が動作しているが、第2 "StudentRepository1は" トン をdoesnのどうすれば修正できますか？あなたに感謝します。

Answer 1

私はあなたのHQLにタイプミスがあると思います。代わりにetudiantsの、Etudiant

@Repository("studentRepository1") 
public interface StudentRepository1 extends JpaRepository<Etudiant, String> { 

    // "Etudiant" was previously "etudiants" 
    @Query("select s from Etudiant s where s.student_ID = :student_ID") 
    Etudiant findBystudent_ID(@Param("student_ID") String student_ID); 

} 

にそれを変更してみてくださいあなたはまだ

@Autowired 
private StudentRepository studentRepository; 
private StudentRepository1 studentRepository1; 

上のあなたの質問に@Autowiredを逃しているUPDATE はする必要があります：

@Autowired 
private StudentRepository studentRepository; 

@Autowired 
private StudentRepository1 studentRepository1; 

編集を続けているので、あなたの質問に従うことも非常に混乱しています。

Answer 2

あなたは私が私のIDEでエラーを再現StudentServiceImpl

であなたのstudentRepository1を配線しませんでした。このブロックを下に見てください。そして、すべてがうまくいくでしょう。

@Autowired 
private StudentRepository studentRepository; 
@Autowired 
private StudentRepository1 studentRepository1;