Question

我让这段代码正常工作

String hql = "FROM Employee ORDER BY last_name";  
Query query = session.createQuery(hql);  
employeeList = query.list();

我尝试了这段代码，但失败了

String hql = "FROM Employee E ORDER BY E.last_name";
Query query = session.createQuery(hql);
employeeList = query.list();

这是例外

Exception in thread "main" java.lang.IllegalArgumentException: org.hibernate.QueryException: could not resolve property: last_name of: com.hibernate.exercise6.model.Employee [FROM com.hibernate.exercise6.model.Employee E ORDER BY E.last_name]
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:131)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:162)
at org.hibernate.internal.AbstractSharedSessionContract.createQuery(AbstractSharedSessionContract.java:631)
at org.hibernate.internal.AbstractSharedSessionContract.createQuery(AbstractSharedSessionContract.java:101)
at com.hibernate.exercise6.service.EmployeeFunctions.listEmployees(EmployeeFunctions.java:208)
at com.hibernate.exercise6.app.GUIMain.displayListMenu(GUIMain.java:329)
at com.hibernate.exercise6.app.GUIMain.manageRecords(GUIMain.java:140)
at com.hibernate.exercise6.app.GUIMain.main(GUIMain.java:62)
Caused by: org.hibernate.QueryException: could not resolve property: last_name of: com.hibernate.exercise6.model.Employee [FROM com.hibernate.exercise6.model.Employee E ORDER BY E.last_name]
at org.hibernate.QueryException.generateQueryException(QueryException.java:120)
at org.hibernate.QueryException.wrapWithQueryString(QueryException.java:103)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:218)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:142)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:115)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:77)
at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:152)
at org.hibernate.internal.AbstractSharedSessionContract.getQueryPlan(AbstractSharedSessionContract.java:521)
at org.hibernate.internal.AbstractSharedSessionContract.createQuery(AbstractSharedSessionContract.java:623)
... 5 more
Caused by: org.hibernate.QueryException: could not resolve property: last_name of: com.hibernate.exercise6.model.Employee
at org.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:62)
at org.hibernate.persister.entity.AbstractPropertyMapping.toType(AbstractPropertyMapping.java:56)
at org.hibernate.persister.entity.AbstractEntityPersister.toType(AbstractEntityPersister.java:1801)
at org.hibernate.hql.internal.ast.tree.FromElementType.getPropertyType(FromElementType.java:393)
at org.hibernate.hql.internal.ast.tree.FromElement.getPropertyType(FromElement.java:505)
at org.hibernate.hql.internal.ast.tree.DotNode.getDataType(DotNode.java:660)
at org.hibernate.hql.internal.ast.tree.DotNode.prepareLhs(DotNode.java:264)
at org.hibernate.hql.internal.ast.tree.DotNode.resolve(DotNode.java:204)
at org.hibernate.hql.internal.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:109)
at org.hibernate.hql.internal.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:104)
at org.hibernate.hql.internal.ast.HqlSqlWalker.resolve(HqlSqlWalker.java:1013)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.expr(HqlSqlBaseWalker.java:1286)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.orderExpr(HqlSqlBaseWalker.java:1860)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.orderExprs(HqlSqlBaseWalker.java:1657)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.orderClause(HqlSqlBaseWalker.java:1630)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:652)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:311)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:259)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:262)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:190)
... 11 more

Employee.java

package com.hibernate.exercise6.model;

import java.util.Set;
import java.util.Comparator;

public class Employee extends Id{
private int uniqueId;
private Name nameInfo;
private Address addressInfo;
private OtherInfo otherInfo;
private Set contact;
private Set role;

public Employee() {}

public Employee(Name nameInfo, Address addressInfo, OtherInfo otherInfo){
    this.nameInfo = nameInfo;
    this.addressInfo = addressInfo;
    this.otherInfo = otherInfo;
}

public void setId(int uniqueId){
    this.uniqueId = uniqueId;
}
public int getId(){
    return uniqueId;
}

public void setName(Name nameInfo){
    this.nameInfo = nameInfo;
}
public Name getName(){
    return nameInfo;
}

public void setAddress(Address addressInfo){
    this.addressInfo = addressInfo;
}
public Address getAddress(){
    return addressInfo;
}

public void setOtherInfo(OtherInfo otherInfo){
    this.otherInfo = otherInfo;
}
public OtherInfo getOtherInfo(){
    return otherInfo;
}

public void setContacts(Set contact){
    this.contact = contact;
}
public Set getContacts(){
    return contact;
}

public void setRole(Set role){
    this.role = role;
}
public Set getRole(){
    return role;
}

public static Comparator<Employee> employeeGwaComparator = new Comparator<Employee>(){
    public int compare(Employee emp1, Employee emp2){
        String emp1Gwa = String.valueOf(emp1.otherInfo.getGwa());
        String emp2Gwa = String.valueOf(emp2.otherInfo.getGwa());

        return emp1Gwa.compareTo(emp2Gwa);
    }       
};
}

Name.java

package com.hibernate.exercise6.model;

public class Name{
private String firstName,
                                lastName,
                                middleName,
                                suffix,
                                title;

public Name() {}

public Name(String title, String firstName, String middleName, String lastName, String suffix){
    this.title = title;
    this.firstName = firstName;
    this.middleName = middleName;
    this.lastName = lastName;
    this.suffix = suffix;
}

public void setTitle(String title){
    this.title = title;
}
public String getTitle(){
    return title;
} 

public void setFirstName(String firstName){
    this.firstName = firstName;
}
public String getFirstName(){
    return firstName;
}

public void setMiddleName(String middleName){
    this.middleName = middleName;
}
public String getMiddleName(){
    return middleName;
}

public void setLastName(String lastName){
    this.lastName = lastName;
}
public String getLastName(){
    return lastName;
}

public void setSuffix(String suffix){
    this.suffix = suffix;
}
public String getSuffix(){
    return suffix;
}
}

不应该是第一个代码和第二个代码的行为方式相同吗？只引入了一个别名，我是否正确？

Answer 1

在HQL中，您可以通过实体的属性访问实际列名称。在您的情况下，属性名称为lastName，列名称为last_name。因此，如果您使用HQL，则必须使用属性，如果要实现NativeQuery，则可以使用列名。

您正在SELECT实体上执行Employee条款，其中name属性为lastName，最后一个属性为String hql = "FROM Employee E ORDER BY E.name.lastName"; Query query = session.createQuery(hql); employeeList = query.list();。所以你的查询必须写成如下：

typedef struct libvlc_media_track_t
{
  /* Codec fourcc */
  uint32_t    i_codec;
  uint32_t    i_original_fourcc;
  int         i_id;
  libvlc_track_type_t i_type;

  /* Codec specific */
  int         i_profile;
  int         i_level;

  union {
      libvlc_audio_track_t *audio;
      libvlc_video_track_t *video;
      libvlc_subtitle_track_t *subtitle;
  };

  unsigned int i_bitrate;
  char *psz_language;
  char *psz_description;
} libvlc_media_track_t;

引起：org.hibernate.QueryException：无法解析属性：last_name

1 个答案: