Hibernate註解執行內部聯接

Question

你好，我剛開始學習休眠。請糾正我在哪裏做錯了。我想用一個使用hibernate註釋的連接表在兩個表之間建立一對多的關係。

create table assembly 
(
    assembly_id serial primary key, 
    number  text, 
    user_id  int 
); 

    create table assembly_properties 
(
    property_id serial primary key, 
    property_name text, 
    property_type  text 
); 

create table assembly_properties_mapping 
(
mapping_id  serial primary key, 
assembly_id  int, 
property_id  int, 
property_value text, 
CONSTRAINT FK_assembly_id FOREIGN KEY (assembly_id) REFERENCES assembly(assembly_id), 
CONSTRAINT FK_property_id  FOREIGN KEY (property_id)  REFERENCES assembly_properties(property_id) 
    ); 

我已經在postgres sql數據庫中創建了這三個表。下面是我Assembly.class

 package com.development.wrapper; 


     @Entity 
     @Table(name = "assembly") 
     public class Assembly { 


      @Id 
      @GeneratedValue(strategy = GenerationType.IDENTITY) 
      @Column(name = "assembly_id") 
       private int assembly_id; 


      @Column(name = "number") 
      private String number; 



      @Column(name ="UserID") 
      private int userId; 


      @Column 
      @ElementCollection(targetClass = AssemblyProperties.class) 
      private Set<AssemblyProperties> assembly_properties; 

      public int getAssembly_id() { 
       return assembly_id; 
      } 

      public void setAssembly_id(int assembly_id) { 
       this.assembly_id = assembly_id; 
      } 

      public String getNumber() { 
       return number; 
      } 

      public void setNumber(String number) { 
       this.number = number; 
      } 

      public int getUserId() { 
       return userId; 
      } 

      public void setUserId(int userId) { 
       this.userId = userId; 
      } 

      @OneToMany(targetEntity = AssemblyProperties.class, cascade = CascadeType.ALL) 
      @JoinTable(name = "assembly_properties_mapping", joinColumns = { @JoinColumn(name = "assembly_id") }, inverseJoinColumns = { @JoinColumn(name = "property_id") }) 


      public Set<AssemblyProperties> getAssembly_properties() { 
       return assembly_properties; 
      } 

      public void setAssembly_properties(Set<AssemblyProperties> assembly_properties) { 
       this.assembly_properties = assembly_properties; 
      } 

     } 

下面是AssemblyProperties.class 包com.development.wrapper;

 @Entity 
     @Table(name = "assembly_properties") 
     public class AssemblyProperties { 
      @Id 
      @GeneratedValue(strategy = GenerationType.IDENTITY) 
      @Column(name = "property_id") 
       private int property_id; 

      @Column(name = "property_name") 
      private String property_name; 

      @Column(name = "property_type") 
      private String property_type; 

      public int getProperty_id() { 
       return property_id; 
      } 

      public void setProperty_id(int property_id) { 
       this.property_id = property_id; 
      } 

      public String getProperty_name() { 
       return property_name; 
      } 

      public void setProperty_name(String property_name) { 
       this.property_name = property_name; 
      } 

      public String getProperty_type() { 
       return property_type; 
      } 

      public void setProperty_type(String property_type) { 
       this.property_type = property_type; 
      } 

     } 

當我試圖給出在數據庫表中加載數據低於我越來越無法創建SessionFactory的object.org.hibernate.MappingException錯誤：無法確定類型：com.development.wrapper。 AssemblyProperties，在表：Assembly_assembly_properties，爲列：[org.hibernate.mapping.Column（assembly_properties） 異常線程 「main」 java.lang.ExceptionInInitializerError

下面

的代碼我試圖運行

 public class Test 
     { 
      SessionFactory factory; 

      public Test() throws Exception 
      { 

        try 
        { 
          factory = new AnnotationConfiguration().configure(). 
           addPackage("com.development.wrapper"). //add package if used. 
              addAnnotatedClass(Assembly.class).buildSessionFactory(); 
        } 
        catch (Throwable ex) 
        { 
          System.err.println("Failed to create sessionFactory object." + ex); 
          throw new ExceptionInInitializerError(ex); 
        } 

      } 


      public Integer addClass(Assembly assembly) 
      { 
        Session session = factory.openSession(); 
        Transaction tx = null; 
        Integer assemblyid = null; 

        try 
        { 
          tx = session.beginTransaction(); 

          assemblyid = (Integer) session.save(assembly); 
          System.out.println(assemblyid); 
          tx.commit(); 
        } 
        catch (HibernateException e) 
        { 
          if (tx != null) 
            tx.rollback(); 
          e.printStackTrace(); 
        } 
        finally 
        { 
          session.close(); 
        } 
        return assemblyid; 
      } 

     public static void main(String[] args) throws Exception { 
      Set<AssemblyProperties> assemblyProperties = new HashSet<AssemblyProperties>(); 
      AssemblyProperties ass=new AssemblyProperties(); 
      ass.setProperty_name("xx"); 
      ass.setProperty_type("List"); 
      assemblyProperties.add(ass); 

      Assembly assembly =new Assembly(); 
      assembly.setAssembly_properties(assemblyProperties); 
      assembly.setNumber("aaa"); 
      assembly.setUserId(1); 
      Test test=new Test(); 
      test.addClass(assembly); 


     } 
     } 

請幫我解決這個錯誤/提前致謝。當公共setter和私人領域的批註中一類混合

Answer 1

Hibernate無法處理。

一個可能的解決辦法是讓所有的註釋在公衆制定者，而不是私人領域和公共制定者之間的混合，這樣就可以避免那裏都處於public和private訪問修飾符註釋的情況下。

Answer 2

你的註解是相互矛盾的。這樣的：

@Column 
@ElementCollection(targetClass = AssemblyProperties.class) 
private Set<AssemblyProperties> assembly_properties; 

這：

@OneToMany(targetEntity = AssemblyProperties.class, cascade = CascadeType.ALL) 
@JoinTable(name = "assembly_properties_mapping", joinColumns = { @JoinColumn(name = "assembly_id") }, inverseJoinColumns = { @JoinColumn(name = "property_id") }) 
public Set<AssemblyProperties> getAssembly_properties() { 
       return assembly_properties; 
      } 

只是刪除第一annotaions在私人領域（assembly_properties）。一般混合域/吸氣JPA註釋