我已经创建了一个用于演示的简单员工应用程序，用于在数据库中成功创建执行表（手动插入数据）后，在春季启动中使用h2和h2嵌入db并在h2中嵌入db，但是在获取数据时，我在EmployeeDAO类中得到了nullpointer异常获取sessionFactory.getCurrentSession（）。我已经发布了我的代码结构。请检查并帮助
Hibernateh2demoApplication.java
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
@SpringBootApplication
@ComponentScan("com")
public class Hibernateh2demoApplication {
public static void main(String[] args) {
SpringApplication.run(Hibernateh2demoApplication.class, args);
}
}
EmployeeController.java
import java.util.List;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import com.tcs.model.Employee;
import com.tcs.services.EmployeeServiceImpl;
@RestController
public class EmployeeController {
@GetMapping("/employee")
public List<Employee> getAllEmployee(){
System.out.println("inside Controller");
return new EmployeeServiceImpl().getAllEmployee();
}
EmployeeServiceImpl.jav
import java.util.List;
import com.tcs.model.Employee;
import com.tcs.repositry.EmployeeDAOImpl;
public class EmployeeServiceImpl implements EmployeeService{
@Override
public List<Employee> getAllEmployee() {
// TODO Auto-generated method stub
System.out.println("inside Service");
return new EmployeeDAOImpl().getAllEmployee();
}
}
application.properties
server.port=8181
spring.h2.console.enabled=true
logging.level.org.springframework.web=DEBUG
# Database
db.driver: org.h2.Driver
db.url: jdbc:h2:~/test
db.username: sa
db.password:
# Hibernate
hibernate.dialect: org.hibernate.dialect.H2Dialect
hibernate.show_sql: true
hibernate.hbm2ddl.auto: update
entitymanager.packagesToScan: com
HibernateConfiguration.java
package com.tcs.configuration;
import java.util.Properties;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.hibernate5.HibernateTransactionManager;
import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@Configuration
@EnableTransactionManagement
public class HibernateConfiguration {
@Value("${db.driver}")
private String DB_DRIVER;
@Value("${db.password}")
private String DB_PASSWORD;
@Value("${db.url}")
private String DB_URL;
@Value("${db.username}")
private String DB_USERNAME;
@Value("${hibernate.dialect}")
private String HIBERNATE_DIALECT;
@Value("${hibernate.show_sql}")
private String HIBERNATE_SHOW_SQL;
@Value("${hibernate.hbm2ddl.auto}")
private String HIBERNATE_HBM2DDL_AUTO;
@Value("${entitymanager.packagesToScan}")
private String ENTITYMANAGER_PACKAGES_TO_SCAN;
@Bean
public LocalSessionFactoryBean sessionFactory() {
System.out.println("sessionFactory");
LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
sessionFactory.setDataSource(dataSource());
sessionFactory.setPackagesToScan(ENTITYMANAGER_PACKAGES_TO_SCAN);
Properties hibernateProperties = new Properties();
hibernateProperties.put("hibernate.dialect", HIBERNATE_DIALECT);
hibernateProperties.put("hibernate.show_sql", HIBERNATE_SHOW_SQL);
hibernateProperties.put("hibernate.hbm2ddl.auto", HIBERNATE_HBM2DDL_AUTO);
sessionFactory.setHibernateProperties(hibernateProperties);
return sessionFactory;
}
@Bean
public DataSource dataSource() {
System.out.println("dataSource");
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName(DB_DRIVER);
dataSource.setUrl(DB_URL);
dataSource.setUsername(DB_USERNAME);
dataSource.setPassword(DB_PASSWORD);
return dataSource;
}
@Bean
public HibernateTransactionManager transactionManager() {
System.out.println("transactionManager");
HibernateTransactionManager txManager = new HibernateTransactionManager();
txManager.setSessionFactory(sessionFactory().getObject());
return txManager;
}
}
EmployeeDAOImpl.java
import java.util.List;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import com.tcs.model.Employee;
public class EmployeeDAOImpl implements EmployeeDAO {
@Autowired
public SessionFactory sessionFactory;
@Override
public List<Employee> getAllEmployee() {
System.out.println("inside dao");
Session session = sessionFactory.getCurrentSession();
@SuppressWarnings("unchecked")
List<Employee> list= session.createCriteria(Employee.class).list();
return list;
}
}
通过Spring Boot执行后，我在Session session = sessionFactory.getCurrentSession（）;下遇到以下问题在这行代码上。请提供解决方案。在此先感谢。 java.lang.NullPointerException: null
at com.tcs.repositry.EmployeeDAOImpl.getAllEmployee(EmployeeDAOImpl.java:19) ~[classes/:na]
at com.tcs.services.EmployeeServiceImpl.getAllEmployee(EmployeeServiceImpl.java:19) ~[classes/:na]
at com.tcs.controller.EmployeeController.getAllEmployee(EmployeeController.java:20) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_74]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_74]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_74]
at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_74]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.13.jar:9.0.13]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:791) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417) [tomcat-embed-core-9.0.13.jar:9.0.13]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.13.jar:9.0.13]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_74]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_74]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.13.jar:9.0.13]
at java.lang.Thread.run(Unknown Source) [na:1.8.0_74]