当我尝试显示来自EmergencyContact的数据时，我得到以下异常。 SurveyData和EmergencyData与OneToMany相关。我能够保留数据，但无法将其恢复。
我想提供一个SurveyID作为输入，并获得该调查的紧急联系人。我验证了所有的setter和getter方法，看起来没问题。我无法追查我弄错的地方。任何帮助表示赞赏。
16:53:42,029 ERROR [stderr] (http-localhost-127.0.0.1-8080-1) Caused by: org.hibernate.QueryException: could not resolve property: survey_id of: masonsurveyejb.businesslogic.EmergencyContact [SELECT emc FROM masonsurveyejb.businesslogic.EmergencyContact emc WHERE emc.survey_id = 11]
我的查询字符串如下所示。我在此方法中收到survey_id变量值作为参数。
"SELECT emc FROM EmergencyContact emc WHERE emc.survey_id = " + survey_id
以下是我的EmergencyContact和SurveyData类
package masonsurveyejb.businesslogic;
import java.io.Serializable;
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.SequenceGenerator;
import javax.persistence.Table;
@Entity
@Table(name = "EmergencyData")
public class EmergencyContact implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@SequenceGenerator(name = "EMERGENCY_SEQUENCE", sequenceName = "Survey_Seq", initialValue = 100, allocationSize = 1)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "EMERGENCY_SEQUENCE")
private Integer contactId;
@Column(name = "Name")
private String emName;
@Column(name = "Phone")
private String emPhone;
@Column(name = "Email")
private String emEmail;
@ManyToOne
@JoinColumn(name = "SurveyID")
private SurveyData surveyData;
public Integer getContactId() {
return contactId;
}
public void setContactId(Integer contactId) {
this.contactId = contactId;
}
public SurveyData getSurveyData() {
return surveyData;
}
public void setSurveyData(SurveyData surveyData) {
this.surveyData = surveyData;
}
public String getEmName() {
return emName;
}
public void setEmName(String emName) {
this.emName = emName;
}
public String getEmPhone() {
return emPhone;
}
public void setEmPhone(String emPhone) {
this.emPhone = emPhone;
}
public String getEmEmail() {
return emEmail;
}
public void setEmEmail(String emEmail) {
this.emEmail = emEmail;
}
}
///////////////////////////////////////////////////////////////////////////////
// @filename: Student.java
// @description: This file is the a simple class which is used as a model
// object for Student.
//
// Modification History
// Date Author Change Reason
// ==== ====== =============
// 2014-02-20 Santosh K Tadikonda Initial Creation
//
///////////////////////////////////////////////////////////////////////////////
package masonsurveyejb.businesslogic;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.SequenceGenerator;
@Entity
public class SurveyData {
@Id
@SequenceGenerator(name = "SURVEY_SEQUENCE", sequenceName = "Survey_Seq", initialValue = 100, allocationSize = 1)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SURVEY_SEQUENCE")
@Column(name = "SurveyID")
private Integer survey_id;
private String firstname;
private String lastname;
private String address;
private String city;
private String state;
private String zipcode;
private String telephone;
private String email;
private String surveydate;
@Column(name = "Likes")
private String chklike;
@Column(name = "Know")
private String radioknow;
private String recommend;
private String raffle;
private String comments;
@OneToMany(mappedBy = "surveyData", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private List<EmergencyContact> emContacts;
public List<EmergencyContact> getEmContacts() {
return emContacts;
}
public void setEmContacts(List<EmergencyContact> emContacts) {
this.emContacts = emContacts;
}
public Integer getSurvey_id() {
return survey_id;
}
public void setSurvey_id(Integer survey_id) {
this.survey_id = survey_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 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 String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getZipcode() {
return zipcode;
}
public void setZipcode(String zipcode) {
this.zipcode = zipcode;
}
public String getTelephone() {
return telephone;
}
public void setTelephone(String telephone) {
this.telephone = telephone;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getSurveydate() {
return surveydate;
}
public void setSurveydate(String surveydate) {
this.surveydate = surveydate;
}
public String getChklike() {
return chklike;
}
public void setChklike(String chklike) {
this.chklike = chklike;
}
public String getRadioknow() {
return radioknow;
}
public void setRadioknow(String radioknow) {
this.radioknow = radioknow;
}
public String getRecommend() {
return recommend;
}
public void setRecommend(String recommend) {
this.recommend = recommend;
}
public String getRaffle() {
return raffle;
}
public void setRaffle(String raffle) {
this.raffle = raffle;
}
public String getComments() {
return comments;
}
public void setComments(String comments) {
this.comments = comments;
}
public String toString() {
String studentString;
studentString = getSurvey_id() + ";" +getFirstname() + ";" + getLastname() + ";"
+ getAddress() + ";" + getCity() + ";" + getState() + ";"
+ getZipcode() + ";" + getTelephone() + ";" + getEmail() + ";"
+ getSurveydate() + ";" + getChklike() + ";" + getRadioknow()
+ ";" + getRecommend() + ";" + getRaffle() + ";"
+ getComments();
return studentString;
}
}
以下是我进行查询的方法
@Override
public ArrayList<EmergencyContact> GetEmergencyContacts(String survey_id) {
try {
if (survey_id == null || survey_id.length() == 0) {
System.out.println("Received a null or empty survey ID.");
return null;
}
System.out.println("Getting emergency contacts for " + survey_id);
String queryStr = "SELECT emc FROM EmergencyContact emc WHERE emc.survey_id = "
+ survey_id;
Query query = entityManager.createQuery(queryStr);
List resultList = query.getResultList();
if (resultList != null && resultList.size() > 0) {
ArrayList<EmergencyContact> emList = new ArrayList<EmergencyContact>();
for (Object result : resultList) {
EmergencyContact emc = new EmergencyContact();
emc = (EmergencyContact) result;
emList.add(emc);
}
return emList;
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
答案 0 :(得分：0)
您收到例外是因为实体＆＃39; EmergencyContact＆＃39;没有名为＆＃39; survey_id＆＃39;。
的财产您的查询应该是：
String queryStr = "SELECT emc FROM EmergencyContact emc WHERE emc.surveyData.survey_id = :id";
Query query = entityManager.createQuery(queryStr).setParameter("id", survey_id);
List resultList = query.getResultList();
请考虑以下两点：