java - 关闭sessionFactory将数据保存到HSQL

Question

我使用 HSQL 作为数据库并使用 Hibernate 编写应用程序。找到以下应用程序。

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>

    <session-factory>
        <property name="hibernate.hbm2ddl.auto">create</property>

        <!-- Database Connection settings -->
        <property name="connection.driver_class">org.hsqldb.jdbcDriver</property>
        <property name="connection.url">jdbc:hsqldb:file:employeeDb;shutdown=true;hsqldb.write_delay=false;</property>
        <property name="connection.username">sa</property>
        <property name="connection.password"></property>

        <!-- Enable the logging of all the generated SQL statements to the console -->
        <property name="show_sql">true</property>

        <!-- Format the generated SQL statement to make it more readable, -->
        <property name="format_sql">false</property>

        <!-- Hibernate will put comments inside all generated SQL statements to 
            hint what’s the generated SQL trying to do -->
        <property name="use_sql_comments">false</property>

        <!-- This property makes Hibernate generate the appropriate SQL for the 
            chosen database. -->
        <property name="dialect">org.hibernate.dialect.HSQLDialect</property>

        <!-- mappings for annotated classes -->
        <mapping class="com.sample.Employee" />

    </session-factory>

</hibernate-configuration>

Employee.java

package com.sample;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Employee {
    @Id
    private int id;
    private String firstName;
    private String lastName;
    private String designation;
    private int age;
    private double salary;

    public Employee(){

    }

    public Employee(int id, String firstName, String lastName, String designation, int age, double salary) {
        super();
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.designation = designation;
        this.age = age;
        this.salary = salary;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = 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 getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public double getSalary() {
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }

}

TestEmployee.java

package com.sample;

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

public class TestEmployee {

    /* Step 1: Create session factory */
    private static SessionFactory getSessionFactory() {

        SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();

        return sessionFactory;
    }

    public static void main(String args[]) {
        Employee emp1 = new Employee(1, "Hari Krishna", "Gurram", "Senior Software Developer", 26, 80000);
        Employee emp2 = new Employee(2, "Shreyas", "Desai", "Team Manager", 35, 150000);
        Employee emp3 = new Employee(3, "Piyush", "Rai", "Senior Software Developer", 26, 100000);
        Employee emp4 = new Employee(4, "Maruti", "Borker", "Software Developer", 26, 60000);

        SessionFactory sessionFactory = getSessionFactory();
        Session session = sessionFactory.openSession();
        session.beginTransaction();
        session.save(emp1);
        session.save(emp2);
        session.save(emp3);
        session.save(emp4);
        session.flush();
        session.getTransaction().commit();

        session.close();
        //sessionFactory.close();

    }
}

当我取消注释“TestEmployee.java”文件中的“sessionFactory.close()”行时，应用程序可以完美保存数据。但是当我评论“sessionFactory.close()”行时，我的数据没有被保存。为什么需要关闭sessionFactory？有什么方法可以在不关闭 sessionFactory 的情况下保留数据吗？

查找堆栈跟踪

INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@a22cb6a] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
Hibernate: create table Employee (id integer not null, age integer not null, designation varchar(255), firstName varchar(255), lastName varchar(255), salary double not null, primary key (id))
Nov 09, 2016 6:22:08 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:524)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:470)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.createTable(AbstractSchemaMigrator.java:273)
    at org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:71)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:203)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:110)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:177)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:66)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:309)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:445)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:710)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)
    at com.sample.TestEmployee.<clinit>(TestEmployee.java:8)
Caused by: java.sql.SQLException: Table already exists: EMPLOYEE in statement [create table Employee]
    at org.hsqldb.jdbc.Util.sqlException(Unknown Source)
    at org.hsqldb.jdbc.jdbcStatement.fetchResult(Unknown Source)
    at org.hsqldb.jdbc.jdbcStatement.execute(Unknown Source)
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54)
    ... 13 more

Hibernate: insert into Employee (age, designation, firstName, lastName, salary, id) values (?, ?, ?, ?, ?, ?)
Hibernate: insert into Employee (age, designation, firstName, lastName, salary, id) values (?, ?, ?, ?, ?, ?)
Hibernate: insert into Employee (age, designation, firstName, lastName, salary, id) values (?, ?, ?, ?, ?, ?)
Hibernate: insert into Employee (age, designation, firstName, lastName, salary, id) values (?, ?, ?, ?, ?, ?)
Nov 09, 2016 6:22:08 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl stop
INFO: HHH10001008: Cleaning up connection pool [jdbc:hsqldb:file:employeeDb;shutdown=true;hsqldb.write_delay=false;]

Answer 1

正如您的评论澄清了情况一样，这是 HSQLDB 的正常行为。它将存储所有从工作文件到持久日志文件的信息(由于 shutdown=true)。为了使其工作，您需要在应用程序终止之前关闭工厂。要自动化此过程，只需使用 shutdown hook Runtime.addShutdownHook(Thread)像这样

Runtime.getRuntime().addShutdownHook(new Thread(){
    public void run(){

       //CLOSE SESSION FACTORY HERE
     }
});

所以基本上，您的更改在您的情况下得到了保留，但是您无法从应用程序外部看到它们，因为当您在不同的进程中再次启动 HSQLDB 时(例如从数据库查看器或 Eclipse IDE 中构建)，它们没有恢复数据库工具)