尝试配置弹簧引导时出现NullPointerException＆posgres

-1

我在Spring引导和postgres中是全新的，我的应用程序在运行时抛出空指针异常。尝试配置弹簧引导时出现NullPointerException＆posgres

这里是我的应用程序的完整代码

application.properties

security.basic.enabled=false 
server.port= 9002 
spring.datasource.url=jdbc:postgresql://127.0.0.1:5432/postgres 

spring.datasource.username = postgres 
spring.datasource.password = admin 
spring.jpa.generate-ddl=true 
# JPA/Hibernate properties 
spring.jpa.show-sql = true 

# Hibernate ddl auto (create, create-drop, update): with "update" the database 
# schema will be automatically updated accordingly to java entities found in project 
spring.jpa.hibernate.ddl-auto = update 
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQLDialect

DepartmentDao.java

@Transactional 
@Repository 
public class DepartmentDao implements IDepartmentDao { 
    @PersistenceContext 
    private EntityManager entityManager; 

    @SuppressWarnings("unchecked") 
    @Override 
    public List<Department> getAllDepartments() { 
     System.out.println("From Dao"); 
     String hql = "SELECT c FROM dod.data.entity.DepartmentEntity as c"; 
     return (List<Department>) entityManager.createQuery(hql).getResultList(); // this is line number 34 
} 
}

有介于两者之间，但问题控制器和服务层是不是与那些层，因为我可以看到控制台正在记录From Dao

DepartmentEntity.java

package dod.data.entity; 
import javax.persistence.*; 
import java.io.Serializable; 
@Entity 
@Table(name = "department", schema = "public", catalog = "postgres") 
public class DepartmentEntity implements Serializable { 
    private static final long serialVersionUID = -18211674104610390L; 
    private int id; 
    private String dept; 
    private int empId; 

    @Id 
    @Column(name = "id", nullable = false) 
    public int getId() { 
     return id; 
    } 

    public void setId(int id) { 
     this.id = id; 
    } 

    @Basic 
    @Column(name = "dept", nullable = false, length = 50) 
    public String getDept() { 
     return dept; 
    } 

    public void setDept(String dept) { 
     this.dept = dept; 
    } 

    @Basic 
    @Column(name = "emp_id", nullable = false) 
    public int getEmpId() { 
     return empId; 
    } 

    public void setEmpId(int empId) { 
     this.empId = empId; 
    } 

    @Override 
    public boolean equals(Object o) { 
     if (this == o) return true; 
     if (o == null || getClass() != o.getClass()) return false; 

     DepartmentEntity that = (DepartmentEntity) o; 

     if (id != that.id) return false; 
     if (empId != that.empId) return false; 
     if (dept != null ? !dept.equals(that.dept) : that.dept != null) return false; 

     return true; 
    } 

    @Override 
    public int hashCode() { 
     int result = id; 
     result = 31 * result + (dept != null ? dept.hashCode() : 0); 
     result = 31 * result + empId; 
     return result; 
    } 
}

错误

2017-08-12 22:54:26.572 ERROR 12596 --- [nio-9002-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause 

java.lang.NullPointerException: null 
    at dod.data.dao.DepartmentDao.getAllDepartments(DepartmentDao.java:34) ~[classes/:na] 
    at dod.data.service.DepartmentService.getAllDepartments(DepartmentService.java:19) ~[classes/:na] 
    at dod.data.DoddataApplication.test(DoddataApplication.java:22) ~[classes/:na] 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_131] 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_131] 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_131] 
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_131] 
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:208) ~[spring-security-web-4.2.3.RELEASE.jar:4.2.3.RELEASE] 
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177) ~[spring-security-web-4.2.3.RELEASE.jar:4.2.3.RELEASE] 
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_131] 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_131] 
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.16.jar:8.5.16] 
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_131]

我使用的IntelliJ &它连接到Postgres的。我还包括春季靴子所需的罐子。

我跟着这个link for spring boot & this for postgres config。不知道我在哪里犯错。

来源

2017-08-12 brk

你介意在GitHub上分享一个项目链接，它重现了这个问题吗？ –

NPE在哪里抛出？实体管理器为空？另一件事是，你可以使用'JPARepository' - 创建查询更容易，它本身提供了很多方法 – ByeBye

你可以共享DepartmentService.class，我想知道如果DepartmentDao是自动装配的。 –

我试图复制你的DepartmentDao代码模拟你的情况，改变一点点在FirstFewLines.com

与例子混合我下载了那里的全部源代码的压缩文件，解压缩它，导入的IntelliJ和添加此类：

package com.firstfewlines.repository; 

import com.firstfewlines.domain.Student; 
import org.springframework.stereotype.Repository; 
import org.springframework.transaction.annotation.Transactional; 

import javax.persistence.EntityManager; 
import javax.persistence.PersistenceContext; 
import java.util.List; 

@Transactional 
@Repository 
public class AnotherRepository { 
    @PersistenceContext 
    private EntityManager entityManager; 

    @SuppressWarnings("unchecked") 
    public List<Student> getAllStudents() { 
     System.out.println("From Dao"); 
     String hql = "SELECT c FROM com.firstfewlines.domain.Student as c"; 
     return (List<Student>) entityManager.createQuery(hql).getResultList(); 
    } 
}

而且这是工作的罚款。

如果你可以分享你的整个代码，我可以看看。

来源

2017-09-24 05:42:27

尝试配置弹簧引导时出现NullPointerException＆posgres

回答

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