Question

我正在尝试按照一个非常基本的JSF教程但是我在第二页（test.xhtml）中得到一个空指针，如果我尝试在那里读取用户名但是在这里找不到我做错了什么。

那是我的豆子：

import java.io.Serializable;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

@ManagedBean
@SessionScoped
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

这是我的第一个面孔：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
          "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html">

<h:head></h:head>
<body>
    <h:form>
        <h:inputText value="#{user.name}" />
        <h:commandLink action="test" value="go" />
    </h:form>
</body>
</html>

我想在这张脸上打印这个名字：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
          "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html">

<h:head></h:head>
<body>
    <h:form>
        <h:outputText value="#{user.name}" />
    </h:form>
</body>
</html>

这里的错误是什么？

编辑： Stacktrace：

00:09:04,468 ERROR [io.undertow.request] (default task-8) UT005023: Exception handling request to /TestJSF/index.xhtml;jsessionid=WmQDd1vj88TJk7m3GC8DuHSo.xxx: javax.servlet.ServletException: /index.xhtml @10,39 value="#{user.name}": Target Unreachable, identifier 'user' resolved to null
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:659)
    at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:86)
    at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
    at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
    at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
    at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
    at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
    at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:58)
    at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:70)
    at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
    at io.undertow.security.handlers.SecurityInitialHandler.handleRequest(SecurityInitialHandler.java:76)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:278)
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:255)
    at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:80)
    at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
    at io.undertow.server.Connectors.executeRootHandler(Connectors.java:199)
    at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:774)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:744)
Caused by: javax.el.PropertyNotFoundException: /index.xhtml @10,39 value="#{user.name}": Target Unreachable, identifier 'user' resolved to null
    at com.sun.faces.facelets.el.TagValueExpression.getType(TagValueExpression.java:100)
    at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue(HtmlBasicInputRenderer.java:95)
    at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1045)
    at javax.faces.component.UIInput.validate(UIInput.java:975)
    at javax.faces.component.UIInput.executeValidate(UIInput.java:1248)
    at javax.faces.component.UIInput.processValidators(UIInput.java:712)
    at javax.faces.component.UIForm.processValidators(UIForm.java:253)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1260)
    at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1195)
    at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
    ... 27 more
Caused by: javax.el.PropertyNotFoundException: Target Unreachable, identifier 'user' resolved to null
    at com.sun.el.parser.AstValue.getTarget(AstValue.java:174)
    at com.sun.el.parser.AstValue.getType(AstValue.java:86)
    at com.sun.el.ValueExpressionImpl.getType(ValueExpressionImpl.java:201)
    at org.jboss.weld.el.WeldValueExpression.getType(WeldValueExpression.java:93)
    at org.jboss.weld.el.WeldValueExpression.getType(WeldValueExpression.java:93)
    at com.sun.faces.facelets.el.TagValueExpression.getType(TagValueExpression.java:98)
    ... 39 more

编辑2： faces-config.xml看起来像：

<?xml version="1.0" encoding="UTF-8"?>
<faces-config version="2.2" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-facesconfig_2_2.xsd">
</faces-config>

web.xml：

http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"> 面对Servlet javax.faces.webapp.FacesServlet 1 面对Servlet * .xhtml

  <!-- Date Converter use system time zone instead of UTC -->
  <context-param>
    <param-name>javax.faces.DATETIMECONVERTER_DEFAULT_TIMEZONE_IS_SYSTEM_TIMEZONE</param-name>
    <param-value>true</param-value>
  </context-param>

  <!-- Do not send XML comments to the client -->
  <context-param>
    <param-name>javax.faces.FACELETS_SKIP_COMMENTS</param-name>
    <param-value>true</param-value>
  </context-param>

  <!-- Process zero-length input strings as null values -->
  <context-param>
    <param-name>javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL</param-name>
    <param-value>true</param-value>
  </context-param>

  <!-- Use development mode -->
  <context-param>
    <param-name>javax.faces.PROJECT_STAGE</param-name>
    <param-value>Development</param-value>
  </context-param>
  <context-param>
    <param-name>facelets.DEVELOPMENT</param-name>
    <param-value>true</param-value>
  </context-param>

  <!-- Welcome page -->
  <welcome-file-list>
    <welcome-file>index.xhtml</welcome-file>
  </welcome-file-list>
</web-app>

Answer 1

它接缝，问题是bean没有包（或默认包）。将它移动到实际的包解决了这个问题。

JSF - Managed Bean =重定向后为null

1 个答案: