JSF错误目标无法访问，'null'返回null [英] JSF Error Target Unreachable, 'null' returned null

问题描述

你好大家现在我使用JSF 2.0和EJB3，我使用了Primefaces显示错误消息或成功消息，我有两个问题是
一个当我把Button sumit（JSF命令按钮）下一页错误显示

/register.xhtml @ 26,172 value =＃{userController.user.username}：Target Unreachable，'null'returned null

我的代码是

用户实体

  / * 
 *要更改此模板，请选择工具模板
 *并在编辑器中打开模板。 
 * / 
 
包com.demoejb.entity; 
 
 import java.io.Serializable; 
 import java.util.Date; 
 import java.util.List; 
 import javax.persistence.Basic; 
 import javax.persistence.CascadeType; 
 import javax.persistence.Column; 
 import javax.persistence.Entity; 
 import javax.persistence.GeneratedValue; 
 import javax.persistence.GenerationType; 
 import javax.persistence.Id; 
 import javax.persistence.JoinColumn; 
 import javax.persistence.ManyToOne; 
 import javax.persistence.NamedQueries; 
 import javax.persistence.NamedQuery; 
 import javax.persistence.OneToMany; 
 import javax.persistence.Table; 
 import javax.persistence.Temporal; 
 import javax.persistence.TemporalType; 
 
 / ** 
 * 
 * @author KencyWindy 
 * / 
 @Entity 
 @Table（name =iuser）
 @NamedQueries（{
 @NamedQuery（name =Iuser.findAll，query =SELECT i FROM Iuser i），
 @NamedQuery（name =Iuser.findByUid，query = SELECT i FROM Iuser i WHERE i.uid =：uid），
 @NamedQuery（name =Iuser.findByUsername，query =SELECT i FROM Iuser i WHERE i.username =：username），
 @NamedQuery（name =Iuser.findByPassword，query =SELECT i FROM Iuser i WHERE i.password =：password），
 @NamedQuery（name =Iuser.findByPnum，query = SELECT i FROM Iuser i WHERE i.pnum =：pnum），
 @NamedQuery（name =Iuser.findByZipcode，query =SELECT i FROM Iuser i WHERE i.zipcode =：zipcode），
 @NamedQuery（name =Iuser.findByState，query =SELECT i FROM Iuser i WHERE i.state =：state），
 @NamedQuery（name =Iuser.findByDob，query =SELECT我从Iuser我WHERE i.dob =：dob），
 @NamedQuery（name =Iuser.findByEmail， query =SELECT i FROM Iuser i WHERE i.email =：email），
 @NamedQuery（name =Iuser.findByLastlogin，query =SELECT i FROM Iuser i WHERE i.lastlogin =：lastlogin） ，
 @NamedQuery（name =Iuser.findByRegdate，query =SELECT i FROM Iuser i WHERE i.regdate =：regdate），
 @NamedQuery（name =Iuser.findByAddress，query =SELECT i FROM Iuser i WHERE i.address =：address），
 @NamedQuery（name =Iuser.findByCity，query =SELECT i FROM Iuser i WHERE i.city =：city）} ）
 public class Iuser implements Serializable {
 private static final long serialVersionUID = 1L; 
 @Id 
 @GeneratedValue（strategy = GenerationType.IDENTITY）
 @Basic（optional = false）
 @Column（name =uid）
 private Integer uid ; 
 @Basic（optional = false）
 @Column（name =username）
 private String username; 
 @Basic（optional = false）
 @Column（name =password）
 private String password; 
 @Basic（optional = false）
 @Column（name =pnum）
 private int pnum; 
 @Basic（optional = false）
 @Column（name =zipcode）
 private int zipcode; 
 @Basic（optional = false）
 @Column（name =state）
 private String state; 
 @Basic（optional = false）
 @Column（name =dob）
 @Temporal（TemporalType.TIMESTAMP）
 private Date dob; 
 @Basic（optional = false）
 @Column（name =email）
 private String email; 
 @Column（name =lastlogin）
 @Temporal（TemporalType.TIMESTAMP）
私人日期lastlogin; 
 @Column（name =regdate）
 @Temporal（TemporalType.TIMESTAMP）
 private Date regdate; 
 @Basic（optional = false）
 @Column（name =address）
 private String address; 
 @Basic（optional = false）
 @Column（name =city）
 private String city; 
 @JoinColumn（name =group，referencedColumnName =g_id）
 @ManyToOne（optional = false）
 private Igroup igroup; 
 @OneToMany（cascade = CascadeType.ALL，mappedBy =iuser）
 private List< Irent> irentList; 
 @OneToMany（cascade = CascadeType.ALL，mappedBy =iuser）
 private List< Ipayment> ipaymentList; 
 
 public Iuser（）{
} 
 
 public Iuser（Integer uid）{
 this.uid = uid; 
} 
 
 public Iuser（Integer uid，String username，String password，int pnum，int zipcode，String state，Date dob，String email，String address，String city）{
 this.uid = uid; 
 this.username = username; 
 this.password = password; 
 this.pnum = pnum; 
 this.zipcode = zipcode; 
 this.state = state; 
 this.dob = dob; 
 this.email = email; 
 this.address = address; 
 this.city = city; 
} 
 
 public Integer getUid（）{
 return uid; 
} 
 
 public void setUid（Integer uid）{
 this.uid = uid; 
} 
 
 public String getUsername（）{
 return username; 
} 
 
 public void setUsername（String username）{
 this.username = username; 
} 
 
 public String getPassword（）{
 return password; 
} 
 
 public void setPassword（String password）{
 this.password = password; 
} 
 
 public int getPnum（）{
 return pnum; 
} 
 
 public void setPnum（int pnum）{
 this.pnum = pnum; 
} 
 
 public int getZipcode（）{
 return zipcode; 
} 
 
 public void setZipcode（int zipcode）{
 this.zipcode = zipcode; 
} 
 
 public String getState（）{
 return state; 
} 
 
 public void setState（String state）{
 this.state = state; 
} 
 
 public Date getDob（）{
 return dob; 
} 
 
 public void setDob（Date dob）{
 this.dob = dob; 
} 
 
 public String getEmail（）{
 return email; 
} 
 
 public void setEmail（String email）{
 this.email = email; 
} 
 
 public Date getLastlogin（）{
 return lastlogin; 
} 
 
 public void setLastlogin（Date lastlogin）{
 this.lastlogin = lastlogin; 
} 
 
 public Date getRegdate（）{
 return regdate; 
} 
 
 public void setRegdate（Date regdate）{
 this.regdate = regdate; 
} 
 
 public String getAddress（）{
 return address; 
} 
 
 public void setAddress（String address）{
 this.address = address; 
} 
 
 public String getCity（）{
 return city; 
} 
 
 public void setCity（String city）{
 this.city = city; 
} 
 
 public Igroup getIgroup（）{
 return igroup; 
} 
 
 public void setIgroup（Igroup igroup）{
 this.igroup = igroup; 
} 
 
 public List< Irent> getIrentList（）{
 return irentList; 
} 
 
 public void setIrentList（List< Irent> irentList）{
 this.irentList = irentList; 
} 
 
 public List< Ipayment> getIpaymentList（）{
 return ipaymentList; 
} 
 
 public void setIpaymentList（List< Ipayment> ipaymentList）{
 this.ipaymentList = ipaymentList; 
} 
 
 @Override 
 public int hashCode（）{
 int hash = 0; 
 hash + =（uid！= null？uid.hashCode（）：0）; 
返回哈希; 
} 
 
 @Override 
 public boolean equals（Object object）{
 // TODO：Warning  - 此方法在id字段为没有设置
 if（！（object instanceof Iuser））{
 return false; 
} 
 Iuser其他=（Iuser）对象; 
 if（（this.uid == null&& other.uid！= null）||（this.uid！= null&！this.uid.equals（other.uid））） {
 return false; 
} 
返回true; 
} 
 
 @Override 
 public String toString（）{
 returncom.demoejb.entity.Iuser [uid =+ uid +]; 
} 
 
} 
  

会话Bean类

  / * 
 *要更改此模板，请选择工具模板
 *并在编辑器中打开模板。 
 * / 
 
 package com.demoejb.DAO; 
 
 import com.demoejb.entity.Igroup; 
 import com.demoejb.entity.Iuser; 
 import java.util.List; 
 import javax.ejb.Stateless; 
 import javax.ejb.LocalBean; 
 import javax.persistence.EntityManager; 
 import javax.persistence.PersistenceContext; 
 
 / ** 
 * 
 * @author KencyWindy 
 * / 
 @Stateless 
 @LocalBean 
 public class UserSessionBean { 
 @PersistenceContext（unitName =DemoEJB3-ejbPU）
 private EntityManager em; 
 
 //在下面添加业务逻辑。 （右键单击编辑器并选择
 //插入代码>添加业务方法）
 
 
 
 public void persist（Object object）{
 em.persist（object）; 
} 
 
 public Object persistEntity（Object entity）{
 em.persist（entity）; 
返回实体; 
} 
 
 public Object updateEntity（Object entity）{
 return em.merge（entity）; 
} 
 
 public void removeUser（Iuser user）{
 user = em.find（Iuser.class，user.getUid（））; 
} 
 
 public List< Iuser> getAllUser（）{
 return em.createNamedQuery（Iuser.findAll）。getResultList（）; 
} 
 
 / *如果新用户输入表单
 *，检查用户名和电子邮件如果存在抛出异常，此功能将用于控制器
 * / 
 public Iuser checkExistUser（String email，String username）{
 Iuser entity = null; 
 try {
 javax.persistence.Query query = em.createQuery（从uuser中选择u，其中iuser.email =：email或iuser.username =：username）; 
 query.setParameter（email，email）; 
 query.setParameter（username，username）; 
 entity =（Iuser）query.getResultList（）; 
} catch（Exception e）{
} 
 return entity; 
} 
 
 public Iuser addUser（Iuser user）{
 
 persist（user）; 
返回用户; 
} 
 
 public void persist1（Object object）{
 em.persist（object）; 
} 
 / * 
 *获取数据库中的所有组
 * / 
 public List< Igroup> getGroup（）{
 
 return em.createNamedQuery（Igroup.findAll）。getResultList（）; 
} 
 
 
} 
  

JSF托管Bean课程

  / * 
 *要更改此模板，请选择工具模板
 *并在编辑器中打开模板。 
 * / 
 
 package com.demo.controller; 
 
 import com.demoejb.DAO.UserSessionBean; 
 import com.demoejb.entity.Igroup; 
 import com.demoejb.entity.Iuser; 
 import java.util.Date; 
 import java.util.List; 
 import javax.ejb.EJB; 
 import javax.faces.application.FacesMessage; 
 import javax.faces.context.FacesContext; 
 import javax.faces.model.SelectItem; 
 
 
 / ** 
 * 
 * @author KencyWindy 
 * / 
 public class UserController {
 @EJB 
 private UserSessionBean userSessionBean; 
私人Iuser用户; 
 
 
 
 
 
 
 / **创建UserController * / 
的新实例public UserController（）{
} 
 
 public Iuser getUser（）{
 return user; 
} 
 
 public void setUser（Iuser user）{
 this.user = user; 
} 
 
 public String addUser（）{
 String toReturn =false; 
 String email = user.getEmail（）; 
 String username = user.getUsername（）; 
尝试{
 if（userSessionBean.checkExistUser（email，username）！= null）{
 FacesContext context = FacesContext.getCurrentInstance（）; 
 context.addMessage（null，new FacesMessage（FacesMessage.SEVERITY_INFO，
Error，username or email id has been exists！））; 
 toReturn =False; 
} 
 else {
 Igroup g = new Igroup（）; 
 Date date = new Date（）; 
 java.text.SimpleDateFormat sdf = new java.text.SimpleDateFormat（yyyy-MM-dd HH：mm：ss）; 
 String getDate = sdf.format（date）; 
日期regDate = sdf.parse（getDate）; 
 user.setRegdate（regDate）; 
 user.setLastlogin（regDate）; 
 g.setGId（1）; 
 user.setIgroup（g）; 
 user = userSessionBean.addUser（user）; 
 FacesContext context = FacesContext.getCurrentInstance（）; 
 context.addMessage（null，new FacesMessage（FacesMessage.SEVERITY_INFO，
Sucessful，New user has been created！））; 
 
} 
} catch（异常e）{
} 
 
 return toReturn; 
} 
 
 / * 
 *为用户创建列表组可以选择编辑
 * warning !!!!这个功能可以为管理员
 * / 
 
 public javax.faces.model.SelectItem [] getGrouplist（）{
 SelectItem [] options = null; 
列表< Igroup> lGroups = userSessionBean.getGroup（）; 
 if（lGroups！= null&& lGroups.size（）> 0）{
 int i = 0; 
 options = new SelectItem [lGroups.size（）]; 
（Igroup iGroup：lGroups）{
 options [i ++] = new SelectItem（iGroup.getGId（），iGroup.getGName（））; 
} 
} 
返回选项; 
} 
 
 
} 
  

Face- config

 <？xml version ='1.0'encoding ='UTF-8'？> 
 
<！ -  ===========完整配置文件===================== ===========  - > 
 
< faces-config version =2.0
 xmlns =http://java.sun.com/xml/ns/javaee
 xmlns：xsi = http://www.w3.org/2001/XMLSchema-instance
 xsi：schemaLocation =http://java.sun.com/xml/ns/javaee http://java.sun.com/ XML / NS / JavaEE的/网络facesconfig_2_0.xsd> 
< managed-bean> 
< description> enntire的控制器用户模块< / description> 
< managed-bean-name> userController< / managed-bean-name> 
< managed-bean-class> com.demo.controller.UserController< / managed-bean-class> 
< managed-bean-scope>请求< / managed-bean-scope> 
< / managed-bean> 
< / faces-config> 
  

第二个问题是我没有使用h将组表放入组合框：selectOne

 < h：outputLabel value =Igroup：for =igroup/> 
< h：selectOneMenu id =igroupvalue =＃{userController.user.igroup}title =Igrouprequired =truerequiredMessage =Igroup字段是必需的。 
<！ -  TODO：更新以下可用项目列表的参考 - > 
< f：selectItems value =＃{userController.grouplist}/> 
< / h：selectOneMenu> 
  

当我使用错误发生时，我不知道为什么会发生错误？我从JSFManageBean编写getGrouplist并且有1个方法getAllGroup数据库中的表的当前数据。

解决方案

嘿，我刚刚遇到了一个非常类似的问题，并从Google那里绊倒了。我通过在ManagedBean中创建一个空数据对象来修复它，在您将其映射到的情况下，将修正

private Iuser user;

到

私人Iuser user = new Iuser（）;

在UserController类。

由于我对我自己很新，我无法真正解释为什么，但它帮助我和希望它也解决你的问题...

Hello Everybody now i working with JSF 2.0 and EJB3 and i used Primefaces to display error message or success message, i have two problem are one when i put Button sumit (JSF command button) next page Error display

/register.xhtml @26,172 value="#{userController.user.username}": Target Unreachable, 'null' returned null

my code are

User Entity

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package com.demoejb.entity;

import java.io.Serializable;
import java.util.Date;
import java.util.List;
import javax.persistence.Basic;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

/**
 *
 * @author KencyWindy
 */
@Entity
@Table(name = "iuser")
@NamedQueries({
    @NamedQuery(name = "Iuser.findAll", query = "SELECT i FROM Iuser i"),
    @NamedQuery(name = "Iuser.findByUid", query = "SELECT i FROM Iuser i WHERE i.uid = :uid"),
    @NamedQuery(name = "Iuser.findByUsername", query = "SELECT i FROM Iuser i WHERE i.username = :username"),
    @NamedQuery(name = "Iuser.findByPassword", query = "SELECT i FROM Iuser i WHERE i.password = :password"),
    @NamedQuery(name = "Iuser.findByPnum", query = "SELECT i FROM Iuser i WHERE i.pnum = :pnum"),
    @NamedQuery(name = "Iuser.findByZipcode", query = "SELECT i FROM Iuser i WHERE i.zipcode = :zipcode"),
    @NamedQuery(name = "Iuser.findByState", query = "SELECT i FROM Iuser i WHERE i.state = :state"),
    @NamedQuery(name = "Iuser.findByDob", query = "SELECT i FROM Iuser i WHERE i.dob = :dob"),
    @NamedQuery(name = "Iuser.findByEmail", query = "SELECT i FROM Iuser i WHERE i.email = :email"),
    @NamedQuery(name = "Iuser.findByLastlogin", query = "SELECT i FROM Iuser i WHERE i.lastlogin = :lastlogin"),
    @NamedQuery(name = "Iuser.findByRegdate", query = "SELECT i FROM Iuser i WHERE i.regdate = :regdate"),
    @NamedQuery(name = "Iuser.findByAddress", query = "SELECT i FROM Iuser i WHERE i.address = :address"),
    @NamedQuery(name = "Iuser.findByCity", query = "SELECT i FROM Iuser i WHERE i.city = :city")})
public class Iuser implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "uid")
    private Integer uid;
    @Basic(optional = false)
    @Column(name = "username")
    private String username;
    @Basic(optional = false)
    @Column(name = "password")
    private String password;
    @Basic(optional = false)
    @Column(name = "pnum")
    private int pnum;
    @Basic(optional = false)
    @Column(name = "zipcode")
    private int zipcode;
    @Basic(optional = false)
    @Column(name = "state")
    private String state;
    @Basic(optional = false)
    @Column(name = "dob")
    @Temporal(TemporalType.TIMESTAMP)
    private Date dob;
    @Basic(optional = false)
    @Column(name = "email")
    private String email;
    @Column(name = "lastlogin")
    @Temporal(TemporalType.TIMESTAMP)
    private Date lastlogin;
    @Column(name = "regdate")
    @Temporal(TemporalType.TIMESTAMP)
    private Date regdate;
    @Basic(optional = false)
    @Column(name = "address")
    private String address;
    @Basic(optional = false)
    @Column(name = "city")
    private String city;
    @JoinColumn(name = "group", referencedColumnName = "g_id")
    @ManyToOne(optional = false)
    private Igroup igroup;
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "iuser")
    private List<Irent> irentList;
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "iuser")
    private List<Ipayment> ipaymentList;

    public Iuser() {
    }

    public Iuser(Integer uid) {
        this.uid = uid;
    }

    public Iuser(Integer uid, String username, String password, int pnum, int zipcode, String state, Date dob, String email, String address, String city) {
        this.uid = uid;
        this.username = username;
        this.password = password;
        this.pnum = pnum;
        this.zipcode = zipcode;
        this.state = state;
        this.dob = dob;
        this.email = email;
        this.address = address;
        this.city = city;
    }

    public Integer getUid() {
        return uid;
    }

    public void setUid(Integer uid) {
        this.uid = uid;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public int getPnum() {
        return pnum;
    }

    public void setPnum(int pnum) {
        this.pnum = pnum;
    }

    public int getZipcode() {
        return zipcode;
    }

    public void setZipcode(int zipcode) {
        this.zipcode = zipcode;
    }

    public String getState() {
        return state;
    }

    public void setState(String state) {
        this.state = state;
    }

    public Date getDob() {
        return dob;
    }

    public void setDob(Date dob) {
        this.dob = dob;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Date getLastlogin() {
        return lastlogin;
    }

    public void setLastlogin(Date lastlogin) {
        this.lastlogin = lastlogin;
    }

    public Date getRegdate() {
        return regdate;
    }

    public void setRegdate(Date regdate) {
        this.regdate = regdate;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public Igroup getIgroup() {
        return igroup;
    }

    public void setIgroup(Igroup igroup) {
        this.igroup = igroup;
    }

    public List<Irent> getIrentList() {
        return irentList;
    }

    public void setIrentList(List<Irent> irentList) {
        this.irentList = irentList;
    }

    public List<Ipayment> getIpaymentList() {
        return ipaymentList;
    }

    public void setIpaymentList(List<Ipayment> ipaymentList) {
        this.ipaymentList = ipaymentList;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (uid != null ? uid.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Iuser)) {
            return false;
        }
        Iuser other = (Iuser) object;
        if ((this.uid == null && other.uid != null) || (this.uid != null && !this.uid.equals(other.uid))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "com.demoejb.entity.Iuser[uid=" + uid + "]";
    }

}

Session Bean class

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package com.demoejb.DAO;

import com.demoejb.entity.Igroup;
import com.demoejb.entity.Iuser;
import java.util.List;
import javax.ejb.Stateless;
import javax.ejb.LocalBean;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

/**
 *
 * @author KencyWindy
 */
@Stateless
@LocalBean
public class UserSessionBean {
    @PersistenceContext(unitName = "DemoEJB3-ejbPU")
    private EntityManager em;

    // Add business logic below. (Right-click in editor and choose
    // "Insert Code > Add Business Method")



    public void persist(Object object) {
        em.persist(object);
    }

   public Object persistEntity(Object entity) {
         em.persist(entity);
         return entity;
    }

   public Object updateEntity(Object entity){
    return em.merge(entity);
   }

   public void removeUser(Iuser user){
    user = em.find(Iuser.class, user.getUid());
   }

   public List<Iuser> getAllUser(){
    return em.createNamedQuery("Iuser.findAll").getResultList();
   }

   /*Check username and email if new user enter into form
    * if exist throw exception, this feature will be used in controller
    */
   public Iuser checkExistUser(String email,String username){
        Iuser entity = null;
       try {
            javax.persistence.Query query = em.createQuery("select u from iuser u where iuser.email = : email or iuser.username = :username");
            query.setParameter("email", email);
            query.setParameter("username", username);
            entity = (Iuser) query.getResultList();
       } catch (Exception e) {
       }
        return entity;
   }

   public Iuser addUser(Iuser user){

        persist(user);
       return  user;
   }

    public void persist1(Object object) {
        em.persist(object);
    }
    /*
     * Get all group in database
     */
    public List<Igroup> getGroup() {

        return em.createNamedQuery("Igroup.findAll").getResultList();
    }


}

JSF Managed Bean class

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package com.demo.controller;

import com.demoejb.DAO.UserSessionBean;
import com.demoejb.entity.Igroup;
import com.demoejb.entity.Iuser;
import java.util.Date;
import java.util.List;
import javax.ejb.EJB;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.faces.model.SelectItem;


/**
 *
 * @author KencyWindy
 */
public class UserController {
    @EJB
    private UserSessionBean userSessionBean;
    private Iuser user;






    /** Creates a new instance of UserController */
    public UserController() {
    }

    public Iuser getUser() {
        return user;
    }

    public void setUser(Iuser user) {
        this.user = user;
    }

     public String addUser(){
        String toReturn =  "false";
        String email = user.getEmail();
        String username = user.getUsername();
        try {
                if(userSessionBean.checkExistUser(email, username) != null){
                    FacesContext context = FacesContext.getCurrentInstance();
                     context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO,
                    "Error", "username or email id has been exist!"));
                    toReturn = "False";
                }
                 else   {
                 Igroup g = new Igroup();
                 Date date = new Date();
                 java.text.SimpleDateFormat sdf = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                 String getDate = sdf.format(date);
                 Date regDate = sdf.parse(getDate);
                 user.setRegdate(regDate);
                 user.setLastlogin(regDate);
                 g.setGId(1);
                 user.setIgroup(g);
                 user = userSessionBean.addUser(user);
                 FacesContext context = FacesContext.getCurrentInstance();
                context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO,
                    "Sucessful", "New user has been created!"));

             }
        } catch (Exception e) {
        }

        return toReturn;
    }

    /*
     * Create list group for user can choose to edit
     * warning !!!! this feature it can posible for administrator
     */

     public javax.faces.model.SelectItem[] getGrouplist(){
        SelectItem[] options = null;
        List<Igroup> lGroups = userSessionBean.getGroup();
        if(lGroups != null && lGroups.size() > 0){
            int i = 0 ;
            options = new SelectItem[lGroups.size()];
            for (Igroup iGroup : lGroups){
                options[i++] = new SelectItem(iGroup.getGId(), iGroup.getGName());
            }
        }
        return options;
     }


}

Face- config

<?xml version='1.0' encoding='UTF-8'?>

<!-- =========== FULL CONFIGURATION FILE ================================== -->

<faces-config version="2.0"
    xmlns="http://java.sun.com/xml/ns/javaee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_2_0.xsd">
    <managed-bean>
        <description>Controller for enntire User module</description>
        <managed-bean-name>userController</managed-bean-name>
        <managed-bean-class>com.demo.controller.UserController</managed-bean-class>
        <managed-bean-scope>request</managed-bean-scope>
    </managed-bean>
</faces-config>

Second problem is i not give group table into combobox with h:selectOne

<h:outputLabel value="Igroup:" for="igroup" />
                    <h:selectOneMenu id="igroup" value="#{userController.user.igroup}" title="Igroup" required="true" requiredMessage="The Igroup field is required.">
                        <!-- TODO: update below reference to list of available items-->
                        <f:selectItems value="#{userController.grouplist}"/>
                    </h:selectOneMenu>

When i used error occured, i dont know why occur error? i write getGrouplist from JSFManageBean and have 1 method getAllGroup Current of table in database.

解决方案

Hey, I just ran into a very similar problem and stumbled upon this from Google. I fixed it by creating an empty data object in the ManagedBean that you're mapping it to, in your case that would be correcting

"private Iuser user;"

to

"private Iuser user = new Iuser();"

in the UserController class.

As I'm pretty new to EE myself, I can't really explain why, but it helped me & hope it solves your problem too...

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