Hibernate不会自动创建表，但是在创建表时，它会将值插入表中

时间：2017-06-16 06:16:55

标签： java hibernate hibernate-mapping hibernate-criteria

如果已存在表名员工，则此程序会将值更新到数据库中。如果该表不存在，则它不会创建一个表，而是提供错误消息。有人好心地拍这个。我不确定我的问题在哪里

hibernate.cfg.xml
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM 
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->   
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost/salarymanagement</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>

 <!-- JDBC connection pool -->  
 <property name="connection.pool_size">1</property>

 <!-- SQL dialect -->
 <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

 <!-- Disable the second level cache -->
 <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

 <!-- Echo all executed SQl to stdout-->
<property name="show_sql">true</property>

 <!-- drop and re-create the database schema-->
<property name="hibernate.hbm2ddl.auto">create</property>

<!-- Lists the annotated entity class -->
<mapping class="com.Hibernate.Employee"/>
</session-factory>
</hibernate-configuration>

MainClass 

package com.Hibernate;

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

public class EmployeeExecution 
{
 public static void main(String args[])
 {
 Employee e1 = new Employee(1,"sri",27,30000);
 SessionFactory sessionfactory = new 
 Configuration().configure().buildSessionFactory();
Session session=sessionfactory.openSession();
session.beginTransaction();
session.save(e1);
session.getTransaction().commit();
}

}

POJO班

package com.Hibernate;

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


@Entity 
public class Employee 
{
@Id
private int id;
private String name;
private int age;
private int salary;


public Employee(int id, String name, int age, int salary) {
    super();
    this.id = id;
    this.name = name;
    this.age = age;
    this.salary = salary;
}


public int getId() {
    return id;
}

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

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public int getAge() {
    return age;
}

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

public int getSalary() {
    return salary;
}

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

错误消息

Exception in thread "main" javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not execute statement
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:147)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:162)
at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1441)
at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:491)
at 

org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3201)
    at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2411)
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:467)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:146)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:220)
    at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:68)
    at com.Hibernate.EmployeeExecution.main(EmployeeExecution.java:17)
Caused by: org.hibernate.exception.SQLGrammarException: could not execute statement
    at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:63)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:208)
    at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:45)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3003)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3503)
    at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:89)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:589)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:463)
    at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337)
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39)
    at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1435)
    ... 9 more
Caused by: java.sql.SQLSyntaxErrorException: Table 'salarymanagement.employee' doesn't exist
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:536)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:513)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:115)
    at com.mysql.cj.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:1983)
    at com.mysql.cj.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1826)
    at com.mysql.cj.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2034)
    at com.mysql.cj.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:1970)
    at com.mysql.cj.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5001)
    at com.mysql.cj.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1955)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:205)
    ... 18 more
00:52:26.579 [pool-1-thread-1] DEBUG org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl - Connection pool now considered primed; min-size will be maintained

2 个答案:

答案 0 :(得分：2)

hibernate.cfg.xml文件

`           ＆＃34; - // Hibernate / Hibernate配置DTD 3.0 // EN＆＃34;
          ＆＃34; HTTP：//hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"＆GT; 

<session-factory>  

    <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="connection.url">jdbc:mysql://localhost:3306/ems</property>

    <property name="connection.username">root</property>  
    <property name="connection.password">root</property>

    <property name="hbm2ddl.auto">create</property>  

    <mapping class="com.scs.model.Employee1" />



</session-factory>

`

Employee.java `@Entity 公共类Employee1 {

@Id
private int id; 
private String name;
private int age;
private int salary;


public Employee1(int id, String name, int age, int salary) {
    super();
    this.id = id;
    this.name = name;
    this.age = age;
    this.salary = salary;
}


public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public int getAge() {
    return age;
}
public void setAge(int age) {
    this.age = age;
}
public int getSalary() {
    return salary;
}
public void setSalary(int salary) {
    this.salary = salary;
}

} `

Main.java

`public class Main {

    public static void main(String arg[]){

        //Creating Configuration file
        Configuration cfg = new AnnotationConfiguration().configure();

        //opening session
        Session session = cfg.buildSessionFactory().openSession();

        Transaction transaction = session.beginTransaction();

        Employee1 emp1 = new Employee1(1,"sri",27,30000); 

        session.persist(emp1);

        transaction.commit();
    }`

答案 1 :(得分：1)

请尝试这个

<prop key="hibernate.hbm2ddl.auto">create</prop>

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