可怕的500错误试图获取Hibernate和海报到百里香的MySql信息:(
[英]Dreaded 500 error trying to get MySql info with hibernate and poster into thymeleaf :(
问题描述
Trying to trying to grab names from MySql with Hibernate and via spring boot post them on a simple thyme leaf page but can't figure out what I'm doing wrong for the life of me. 
试图用Hibernate从MySql中获取名称并通过spring boot将它们发布在一个简单的百里香页面上，但无法弄清楚我在生活中做错了什么。 Thanks for any advice. 谢谢你的建议。
Entity: 实体：
@Entity
@Table(name = "customer")
public class Customer {
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Id
private int id;
@Column(name = "first_name")
private String firstName;
@Column(name = "last_name")
private String lastName;
@Column(name = "email")
private String email;
public Customer(){}
@Override
public String toString() {
return "Customer{" +
"id=" + id +
", firstName='" + firstName + '\'' +
", lastName='" + lastName + '\'' +
", email='" + email + '\'' +
'}';
}
public Customer(String firstName, String lastName, String email){
this.firstName = firstName;
this.lastName = lastName;
this.email = email;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
DAO: DAO：
public interface CustomerDAO extends CrudRepository<Customer, Integer> {
public List<Customer> findAll();
}
Controller: 控制器：
@Controller
public class CustomerController {
private CustomerDAO customerDAO;
@RequestMapping("/")
public String listCustomers(Model model){
List<Customer> customers = customerDAO.findAll();
model.addAttribute("customers", customers);
return "home";
}
}
Thymeleaf: Thymeleaf：
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head lang="en">
<title>Title</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
</head>
<body>
<div th:each="customer: ${customers}">
<h3 th:text="${customer}"></h3>
</div>
</body>
</html>
Stack Trace: 堆栈跟踪：
/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/bin/java "-javaagent:/Applications/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar=49470:/Applications/IntelliJ IDEA CE.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath /Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/lib/tools.jar:/Users/ronaldpitt/Desktop/JavaProjects/target/classes:/Users/ronaldpitt/.m2/repository/org/springframework/boot/spring-boot-starter-web/1.5.2.RELEASE/spring-boot-starter-web-1.5.2.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/boot/spring-boot-starter/1.5.2.RELEASE/spring-boot-starter-1.5.2.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/boot/spring-boot/1.5.2.RELEASE/spring-boot-1.5.2.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/1.5.2.RELEASE/spring-boot-autoconfigure-1.5.2.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/boot/spring-boot-starter-logging/1.5.2.RELEASE/spring-boot-starter-logging-1.5.2.RELEASE.jar:/Users/ronaldpitt/.m2/repository/ch/qos/logback/logback-classic/1.1.11/logback-classic-1.1.11.jar:/Users/ronaldpitt/.m2/repository/ch/qos/logback/logback-core/1.1.11/logback-core-1.1.11.jar:/Users/ronaldpitt/.m2/repository/org/slf4j/jul-to-slf4j/1.7.24/jul-to-slf4j-1.7.24.jar:/Users/ronaldpitt/.m2/repository/org/slf4j/log4j-over-slf4j/1.7.24/log4j-over-slf4j-1.7.24.jar:/Users/ronaldpitt/.m2/repository/org/yaml/snakeyaml/1.17/snakeyaml-1.17.jar:/Users/ronaldpitt/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/1.5.2.RELEASE/spring-boot-starter-tomcat-1.5.2.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/8.5.11/tomcat-embed-core-8.5.11.jar:/Users/ronaldpitt/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/8.5.11/tomcat-embed-el-8.5.11.jar:/Users/ronaldpitt/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/8.5.11/tomcat-embed-websocket-8.5.11.jar:/Users/ronaldpitt/.m2/repository/org/hibernate/hibernate-validator/5.3.4.Final/hibernate-validator-5.3.4.Final.jar:/Users/ronaldpitt/.m2/repository/javax/validation/validation-api/1.1.0.Final/validation-api-1.1.0.Final.jar:/Users/ronaldpitt/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.8.7/jackson-databind-2.8.7.jar:/Users/ronaldpitt/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.8.0/jackson-annotations-2.8.0.jar:/Users/ronaldpitt/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.8.7/jackson-core-2.8.7.jar:/Users/ronaldpitt/.m2/repository/org/springframework/spring-web/4.3.7.RELEASE/spring-web-4.3.7.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/spring-aop/4.3.7.RELEASE/spring-aop-4.3.7.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/spring-context/4.3.7.RELEASE/spring-context-4.3.7.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/spring-webmvc/4.3.7.RELEASE/spring-webmvc-4.3.7.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/spring-expression/4.3.7.RELEASE/spring-expression-4.3.7.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/spring-core/4.3.7.RELEASE/spring-core-4.3.7.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/boot/spring-boot-starter-thymeleaf/1.5.2.RELEASE/spring-boot-starter-thymeleaf-1.5.2.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/thymeleaf/thymeleaf-spring4/2.1.5.RELEASE/thymeleaf-spring4-2.1.5.RELEASE.jar:/Users/ronaldpitt/.m2/repository/nz/net/ultraq/thymeleaf/thymeleaf-layout-dialect/1.4.0/thymeleaf-layout-dialect-1.4.0.jar:/Users/ronaldpitt/.m2/repository/org/codehaus/groovy/groovy/2.4.9/groovy-2.4.9.jar:/Users/ronaldpitt/.m2/repository/org/hibernate/hibernate-core/5.2.9.Final/hibernate-core-5.2.9.Final.jar:/Users/ronaldpitt/.m2/repository/org/jboss/logging/jboss-logging/3.3.0.Final/jboss-logging-3.3.0.Final.jar:/Users/ronaldpitt/.m2/repository/org/hibernate/javax/persistence/hibernate-jpa-2.1-api/1.0.0.Final/hibernate-jpa-2.1-api-1.0.0.Final.jar:/Users/ronaldpitt/.m2/repository/org/javassist/javassist/3.21.0-GA/javassist-3.21.0-GA.jar:/Users/ronaldpitt/.m2/repository/antlr/antlr/2.7.7/antlr-2.7.7.jar:/Users/ronaldpitt/.m2/repository/org/jboss/spec/javax/transaction/jboss-transaction-api_1.2_spec/1.0.1.Final/jboss-transaction-api_1.2_spec-1.0.1.Final.jar:/Users/ronaldpitt/.m2/repository/org/jboss/jandex/2.0.3.Final/jandex-2.0.3.Final.jar:/Users/ronaldpitt/.m2/repository/com/fasterxml/classmate/1.3.3/classmate-1.3.3.jar:/Users/ronaldpitt/.m2/repository/dom4j/dom4j/1.6.1/dom4j-1.6.1.jar:/Users/ronaldpitt/.m2/repository/org/hibernate/common/hibernate-commons-annotations/5.0.1.Final/hibernate-commons-annotations-5.0.1.Final.jar:/Users/ronaldpitt/.m2/repository/org/springframework/data/spring-data-commons/1.13.1.RELEASE/spring-data-commons-1.13.1.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/springframework/spring-beans/4.3.7.RELEASE/spring-beans-4.3.7.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/slf4j/slf4j-api/1.7.24/slf4j-api-1.7.24.jar:/Users/ronaldpitt/.m2/repository/org/slf4j/jcl-over-slf4j/1.7.24/jcl-over-slf4j-1.7.24.jar:/Users/ronaldpitt/.m2/repository/mysql/mysql-connector-java/6.0.6/mysql-connector-java-6.0.6.jar:/Users/ronaldpitt/.m2/repository/org/hibernate/hibernate-entitymanager/5.2.9.Final/hibernate-entitymanager-5.2.9.Final.jar:/Users/ronaldpitt/.m2/repository/net/bytebuddy/byte-buddy/1.6.6/byte-buddy-1.6.6.jar:/Users/ronaldpitt/.m2/repository/org/thymeleaf/thymeleaf-spring3/3.0.3.RELEASE/thymeleaf-spring3-3.0.3.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/thymeleaf/thymeleaf/2.1.5.RELEASE/thymeleaf-2.1.5.RELEASE.jar:/Users/ronaldpitt/.m2/repository/org/unbescape/unbescape/1.1.0.RELEASE/unbescape-1.1.0.RELEASE.jar com.luv2code.App
objc[512]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/bin/java (0x1058f74c0) and /Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/lib/libinstrument.dylib (0x1059bf4e0). One of the two will be used. Which one is undefined.
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.2.RELEASE)
2017-04-21 21:24:58.441 INFO 512 --- [ main] com.luv2code.App : Starting App on Ronalds-MacBook-Pro.local with PID 512 (/Users/ronaldpitt/Desktop/JavaProjects/target/classes started by ronaldpitt in /Users/ronaldpitt/Desktop/JavaProjects)
2017-04-21 21:24:58.444 INFO 512 --- [ main] com.luv2code.App : No active profile set, falling back to default profiles: default
2017-04-21 21:24:58.713 INFO 512 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@4ba2ca36: startup date [Fri Apr 21 21:24:58 EDT 2017]; root of context hierarchy
2017-04-21 21:25:00.331 INFO 512 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-04-21 21:25:00.350 INFO 512 --- [ main] o.apache.catalina.core.StandardService : Starting service Tomcat
2017-04-21 21:25:00.352 INFO 512 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.11
2017-04-21 21:25:00.510 INFO 512 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2017-04-21 21:25:00.510 INFO 512 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1803 ms
2017-04-21 21:25:00.719 INFO 512 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2017-04-21 21:25:00.725 INFO 512 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-04-21 21:25:00.726 INFO 512 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-04-21 21:25:00.726 INFO 512 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-04-21 21:25:00.726 INFO 512 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2017-04-21 21:25:01.160 INFO 512 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@4ba2ca36: startup date [Fri Apr 21 21:24:58 EDT 2017]; root of context hierarchy
2017-04-21 21:25:01.252 INFO 512 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto public java.lang.String com.luv2code.controller.CustomerController.listCustomers(org.springframework.ui.Model)
2017-04-21 21:25:01.258 INFO 512 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2017-04-21 21:25:01.258 INFO 512 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2017-04-21 21:25:01.300 INFO 512 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-21 21:25:01.300 INFO 512 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-21 21:25:01.354 INFO 512 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-21 21:25:01.991 INFO 512 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2017-04-21 21:25:02.080 INFO 512 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-04-21 21:25:02.086 INFO 512 --- [ main] com.luv2code.App : Started App in 14.278 seconds (JVM running for 15.114)
2017-04-21 21:25:06.442 INFO 512 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring FrameworkServlet 'dispatcherServlet'
2017-04-21 21:25:06.442 INFO 512 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization started
2017-04-21 21:25:06.466 INFO 512 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 24 ms
2017-04-21 21:25:06.518 ERROR 512 --- [nio-8080-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 com.luv2code.controller.CustomerController.listCustomers(CustomerController.java:23) ~[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-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.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-4.3.7.RELEASE.jar:4.3.7.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-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.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-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.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-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.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-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.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_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-8.5.11.jar:8.5.11]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_131]
2017-04-21 21:25:31.412 INFO 512 --- [ Thread-3] ationConfigEmbeddedWebApplicationContext : Closing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@4ba2ca36: startup date [Fri Apr 21 21:24:58 EDT 2017]; root of context hierarchy
2017-04-21 21:25:31.414 INFO 512 --- [ Thread-3] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
Process finished with exit code 130 (interrupted by signal 2: SIGINT)
1 个解决方案
解决方案1
0 2017-04-22 01:57:55
The problem is that you haven't initialized the customerDAO variable. 问题是您尚未初始化customerDAO变量。 It needs to either be explicitly initialized, or initialized by DI (eg autowiring). 它需要显式初始化，或者由DI初始化（例如自动装配）。
But this line fails with an NPE because customerDAO is null : 但是这条线因NPE而失败，因为customerDAO为null ：
List<Customer> customers = customerDAO.findAll();
Please read the following Answer on how to find / fix NPEs for yourself: 请阅读以下有关如何为自己查找/修复NPE的答案：
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