異常在線程「主」org.hibernate.exception.LockAcquisitionException：無法執行語句

Question

我想更新表中使用Hibernate的記錄，但記錄不更新，並在下次執行它需要很多時間，並引發以下錯誤：Exception in thread "main" org.hibernate.exception.LockAcquisitionException: could not execute statement

員工：

import javax.persistence.CascadeType; 
    import javax.persistence.Entity; 
    import javax.persistence.GeneratedValue; 
    import javax.persistence.Id; 
    import javax.persistence.OneToOne; 
    import javax.persistence.Table; 

    import org.hibernate.annotations.*; 

    @Entity 
    @Table(name = "Emp_Table") 
    public class Employee { 
     @Id 
     @GeneratedValue 
     private int id; 
     private String name; 
     private double salary; 

     @OneToOne(mappedBy = "emp") 
     @Cascade(value = org.hibernate.annotations.CascadeType.ALL) 
     private Address addr; 

     /* Getter-Setter methods */ 
    } 

地址：

import javax.persistence.Column; 
    import javax.persistence.Entity; 
    import javax.persistence.GeneratedValue; 
    import javax.persistence.Id; 
    import javax.persistence.OneToOne; 
    import javax.persistence.PrimaryKeyJoinColumn; 
    import javax.persistence.Table; 

    import org.hibernate.annotations.GenericGenerator; 
    import org.hibernate.annotations.Parameter; 

    @Entity 
    @Table(name = "Addr_Table") 
    public class Address { 

     @Id 
     @Column(name = "eid") 
     @GeneratedValue(generator = "gen") 
     @GenericGenerator(name = "gen", strategy = "foreign", parameters = {@Parameter(name = "property", value = "emp")}) 
     private int id; 
     private String state; 
     private String country; 

     @OneToOne 
     @PrimaryKeyJoinColumn 
     private Employee emp; 

     /* Getter-Setter methods */ 
    } 

HQLExample包含CRUD操作。

package com.Hibernate.Main; 

import java.util.List; 

import org.hibernate.Query; 
import org.hibernate.Session; 
import org.hibernate.SessionFactory; 
import org.hibernate.Transaction; 
import org.hibernate.cfg.Configuration; 

import com.Hibernate.Model.Employee; 
import com.Hibernate.Util.HibernateUtil; 

public class HQLExample { 

    @SuppressWarnings("unchecked") 
    public static void main(String[] args) { 

     SessionFactory factory = new Configuration().configure().buildSessionFactory(); 
     Session session = factory.openSession(); 

     Transaction tx = session.beginTransaction(); 
     Query query = session.createQuery("from Employee"); 
     List<Employee> emp = query.list(); 
     for (Employee empList : emp) { 
      System.out.println("\nID:\t" + empList.getId() + "\nName:\t" + empList.getName() + "\nSalary:\t" 
        + empList.getSalary()); 
     } 

     Query query1 = session.createQuery("from Employee where id = :id"); 
     query1.setInteger("id", 2); 
     Employee empList = (Employee) query1.uniqueResult(); 
     System.out.println(
       "\nID:\t" + empList.getId() + "\nName:\t" + empList.getName() + "\nSalary:\t" + empList.getSalary()); 


     Query query2 = session.createQuery("from Employee"); 
     query2.setFirstResult(1); 
     query2.setFetchSize(1); 
     emp = query2.list(); 
     for (Employee empList1 : emp) { 
      System.out.println("\nID:\t" + empList1.getId() + "\nName:\t" + empList1.getName() + "\nSalary:\t" 
        + empList1.getSalary()); 
     } 

     query = session.createQuery("update Employee set name = :name where id = :id"); 
     query.setParameter("name", "Gaurav"); 
     query.setInteger("id", 2); 
     int result = query.executeUpdate(); 
     System.out.println("\n\nEmployee updated successfully: "+result); 



     query = session.createQuery("delete from Employee where id: eid"); 
     query.setInteger("eid", 4); 
     result = query.executeUpdate(); 
     System.out.println("Employee deleted successfully "+ result);*/ 
    } 
} 

我能夠檢索記錄，但更新記錄期間，它要麼不更新記錄或需要很長的時間，並拋出錯誤：異常線程「main」 org.hibernate.exception.LockAcquisitionException：可能不執行聲明。

使用命令顯示進程列表我試圖殺死那裏處於睡眠模式的進程。殺死那些進程後，我能夠執行更新語句，但它沒有反映到數據庫中。當試圖再次執行代碼時會長時間運行並失敗。

的hibernate.cfg.xml：

<?xml version="1.0" encoding="utf-8"?> 
<!DOCTYPE hibernate-configuration PUBLIC 
     "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 
     "http://hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 
<hibernate-configuration> 
    <session-factory> 
     <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> 
     <property name="hibernate.connection.username">root</property> 
     <property name="hibernate.connection.password">root.123</property> 
     <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/Hibernate</property> 
     <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> 
     <property name="hibernate.current_session_context_class">thread</property> 
     <property name="hibernate.hbm2ddl.auto">update</property> 
     <property name="hibernate.show_sql">true</property> 
     <mapping class="com.Hibernate.Model.Address"></mapping> 
     <mapping class="com.Hibernate.Model.Employee"></mapping> 
    </session-factory> 
</hibernate-configuration> 

Answer 1

您必須承諾的修改保存到數據庫的事務。你也必須關閉會話和會話工廠。如果您沒有關閉資源，則意味着代碼將鎖定數據庫中的記錄。

此外，我觀察到您的刪除查詢語法錯誤。以下是您可以做的改變代碼的工作。

query = session.createQuery("delete from Employee where id = :eid"); 
query.setInteger("eid", 4); 
result = query.executeUpdate(); 
System.out.println("Employee deleted successfully " + result); 

tx.commit(); // commit the transaction 
session.close(); // close the session 
factory.close(); // close the factory