Question

我正在使用inteliJ中的hibernate构建java spring项目。

我在我的项目中包含了hibernate并生成了hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <property name="connection.url">jdbc:mysql://localhost:3306/tornoci</property>
    <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.username">name</property>
    <property name="hibernate.connection.password">123456</property>
    <property name="hibernate.current_session_context_class">thread</property>
    <property name="hibernate.enable_lazy_load_no_trans">true</property>
    <mapping class="com.example.TorkoEntity"/>
      <!-- DB schema will be updated if needed -->
    <!-- <property name="hbm2ddl.auto">update</property> -->
  </session-factory>
</hibernate-configuration>

在application.properties中的

我添加了数据库路径并设置了驱动程序

spring.datasource.url = jdbc:mysql://localhost:3306/tornoci
spring.datasource.username = name
spring.datasource.password = 123456
spring.datasource.driverClassName = com.mysql.jdbc.Driver

我还从数据库表中生成了映射的POJO类。

现在在inteliJ，当去观看时 - ＆gt;工具窗口 - ＆gt;坚持并右键点击

com.example;hibernate.cfg.xml并选择了控制台并执行基本命令

From TorkoEntity

我得到了理想的结果。但是当我创建HibernatUtil类时：

public class NewHibernateUtil {

        private SessionFactory sessionFactory;

        public void setSessionFactory(SessionFactory sessionFactory) {
            this.sessionFactory = sessionFactory;
        }

        NewHibernateUtil(){

        };
        @SuppressWarnings("unchecked")
        public List<TorkoEntity> list() {
            Session session = this.sessionFactory.getCurrentSession();
            List<TorkoEntity> personList = session.createQuery("from TorkoEntity ").list();
            session.close();
            return personList;
        }

    public  SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

并且在路线/索引中我想打印结果，例如

@RestController
public class GreetRoute {
    NewHibernateUtil util;
    @RequestMapping( value = "/index" , method = RequestMethod.GET )
    public List<TorkoEntity> greet(){

        return util.list();
    }
}

我得到了

java.lang.NullPointerException: null
    at com.example.GreetRoute.greet(GreetRoute.java:18) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_65]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_65]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_65]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_65]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_65]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_65]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_65]

错误。

我之前使用了较早版本的hibenate，其中我使用了诸如

之类的sessionFactory

sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();

似乎不再起作用了。我应该如何初始化sessionFactory，从而避免nullptr异常？

非常感谢帮助。感谢。

Answer 1

看起来NewHibernateUtil不会被实例化。如果你在application-context.xml中将它配置为bean，那么你可能需要自动装配util或添加public getter / setter。

 @Autowired
 NewHibernateUtil util;

Hibernate会话工厂始终为null

1 个答案: