Objekt kann nicht mit Spring und Thymeleaf übertragen werden

Ich habe versucht, eine sehr einfache Anwendung mit Spring und Thymeleaf zu erstellen, aber ich habe ein paar Probleme mit den übertragenen Objekten.Objekt kann nicht mit Spring und Thymeleaf übertragen werden

Klasse Person.java:

public class Person { 

private String firstName; 

private String lastName; 

private int age; 

public Person(String firstName, String lastName, int age) { 
    super(); 
    this.firstName = firstName; 
    this.lastName = lastName; 
    this.age = age; 
} 

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 int getAge() { 
    return age; 
} 

public void setAge(int age) { 
    this.age = age; 
}

}

Mein Controller-Klasse PeoplePageCotroller.java wie folgt aussieht:

@Controller 
@RequestMapping({"/people", "/people/"}) 
public class PeoplePageController { 

    @RequestMapping(method = RequestMethod.GET) 
    public String initPeoplePage(Model model) { 

     ArrayList<Person> people = createRandomPeople(5); 

     model.addAttribute("people", people); 
     return "peoplePage"; 
    } 

    private ArrayList<Person> createRandomPeople(int numberOfPeople) { 
     ArrayList<Person> people = new ArrayList<Person>(); 
     for (int i = 0; i < numberOfPeople; i++) { 
      Person person = new Person("FirstName" + i, "LastName" + i, i + 20); 
      people.add(person); 
     } 
     return people; 
    } 
}

das Fragment meiner HTML-Datei wie folgt aussieht:

<table 
        class="col-md-12 table-bordered table-striped table-condensed cf"> 
        <thead class="cf"> 
         <tr> 
          <th>First name</th> 
          <th>Last name</th> 
          <th>Age</th> 
         </tr> 
        </thead> 
        <tbody> 
         <div th:each="person : ${people}"> 
         <tr> 
          <td th:text="${person.firstName}"></td> 
          <td th:text="${person.lastName}"></td> 
          <td th:text="${person.age}"></td> 
         </tr> 
         </div> 
        </tbody> 
       </table>

Im Ergebnis erhalte ich Ausnahme „SpelEvaluationException“ und ich habe keine Ahnung, wie man es beheben:

org.springframework.expression.spel.SpelEvaluationException: EL1007E:(pos 0): Property or field 'firstName' cannot be found on null 
at org.springframework.expression.spel.ast.PropertyOrFieldReference.readProperty(PropertyOrFieldReference.java:220) ~[spring-expression-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:94) ~[spring-expression-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.expression.spel.ast.PropertyOrFieldReference.access$000(PropertyOrFieldReference.java:46) ~[spring-expression-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.expression.spel.ast.PropertyOrFieldReference$AccessorLValue.getValue(PropertyOrFieldReference.java:374) ~[spring-expression-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:88) ~[spring-expression-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:120) ~[spring-expression-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:267) ~[spring-expression-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.thymeleaf.spring4.expression.SpelVariableExpressionEvaluator.evaluate(SpelVariableExpressionEvaluator.java:139) ~[thymeleaf-spring4-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.standard.expression.VariableExpression.executeVariable(VariableExpression.java:154) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.standard.expression.SimpleExpression.executeSimple(SimpleExpression.java:59) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.standard.expression.Expression.execute(Expression.java:103) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.standard.expression.Expression.execute(Expression.java:133) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.standard.expression.Expression.execute(Expression.java:120) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.standard.processor.attr.AbstractStandardTextChildModifierAttrProcessor.getText(AbstractStandardTextChildModifierAttrProcessor.java:68) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.processor.attr.AbstractTextChildModifierAttrProcessor.getModifiedChildren(AbstractTextChildModifierAttrProcessor.java:59) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.processor.attr.AbstractChildrenModifierAttrProcessor.processAttribute(AbstractChildrenModifierAttrProcessor.java:59) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.processor.attr.AbstractAttrProcessor.doProcess(AbstractAttrProcessor.java:87) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.processor.AbstractProcessor.process(AbstractProcessor.java:212) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.applyNextProcessor(Node.java:1017) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:972) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.dom.Document.process(Document.java:93) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1155) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1060) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1011) ~[thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.spring4.view.ThymeleafView.renderFragment(ThymeleafView.java:335) ~[thymeleaf-spring4-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.thymeleaf.spring4.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring4-2.1.4.RELEASE.jar:2.1.4.RELEASE] 
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1246) ~[spring-webmvc-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1029) ~[spring-webmvc-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:973) ~[spring-webmvc-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:895) ~[spring-webmvc-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967) ~[spring-webmvc-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858) ~[spring-webmvc-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843) ~[spring-webmvc-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:87) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE] 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) ~[tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1502) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1458) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_40] 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_40] 
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.0.33.jar:8.0.33] 
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_40]

Quelle

2016-06-13 Konrad

Getter und Setter? – vzamanillo

In der Klasse Person.java sind sie Getter und Setter, ich habe sie einfach nicht kopiert. Korrigiert es. – Konrad

Vielleicht ist das Problem damit zusammen, wie Sie die Iteration werden unter Verwendung der HTML-Tabelle zu erstellen. Sie müssen kein div hinzufügen, um in jeder Zeile zu iterieren, sondern stattdessen das Tag tr. In Ihrem Beispiel:

<table class="col-md-12 table-bordered table-striped table-condensed cf"> 
    <thead class="cf"> 
    <tr> 
     <th>First name</th> 
     <th>Last name</th> 
     <th>Age</th> 
    </tr> 
    </thead> 
    <tbody> 
    <tr th:each="person : ${people}"> 
     <td th:text="${person.firstName}"></td> 
     <td th:text="${person.lastName}"></td> 
     <td th:text="${person.age}"></td> 
    </tr> 
    </tbody> 
</table>

Mehr Informationen in der Thymeleaf Dokumentation über Iteration: http://www.thymeleaf.org/doc/tutorials/2.1/usingthymeleaf.html#using-theach

Quelle

2016-06-14 06:50:34

Ich habe diesen Code von mir ausprobiert und es funktioniert ohne nur jede errors.It passiert, wenn Null-Objekt zu den Menschen hinzugefügt wird Liste.

ex:

ArrayList<Person> people = createRandomPeople(5); 
people.add(null);

Quelle

2016-06-14 12:48:46

Objekt kann nicht mit Spring und Thymeleaf übertragen werden

Antwort

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