生成目标遇到异常接受命令：通过 JDBC 语句执行 DDL 引擎 =MyISAM" 时出错

Question

我在Hibernate中遇到了一个非常奇怪的错误，直到今天才出现，因为昨天一切都正常，我没有对配置文件进行任何更改。看起来java想要执行定义的列并将它们导出到数据库，但随后出现了Error executing DDL engine=MyISAM" via JDBC Statement。

我已经读到，由于hibernate.cfg.xml中的MySQLDialect而不是MySQL5Dialect，可能会出现错误，但这不是问题，因为我从一开始就使用MySQL5Dialect。

我在连接到的本地数据库上操作。

---

休眠.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://www.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.url">jdbc:mysql://localhost:3306/users</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
<property name="show_sql">true</property>
<property name="format_sql">true</property>
<property name="hbm2ddl.auto">update </property> 
<mapping class="UserData"/> 
</session-factory>
</hibernate-configuration>

用户数据.java

import javax.persistence.*;
@Table
@Entity(name="users")
public class UserData {

@Id 
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column
private String firstName;
@Column
private String lastName;
@Column
private int telephoneNo;
@Column
private String email;
@Column
private String pickUp;
@Column
private String dropOff;
public UserData(){}

public UserData(String firstName, String lastName, int telephoneNo, String email, String pickUp, String dropOff){
this.firstName = firstName;
this.lastName = lastName;
this.telephoneNo = telephoneNo;
this.email = email;
this.pickUp = pickUp;
this.dropOff = dropOff;
}

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 int getTelephoneNo() {
return telephoneNo;
}
public void setTelephoneNo(int telephoneNo) {
this.telephoneNo = telephoneNo;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPickUp() {
return pickUp;
}
public void setPickUp(String pickUp) {
this.pickUp = pickUp;
}
public String getDropOff() {
return dropOff;
}
public void setDropOff(String dropOff) {
this.dropOff = dropOff;
}
}

sample.csv

1,Reanna,Colepio,159031625,[e-mail],London,Glasgow

Hibernate Config.java

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

public class HibernateConfig {
private static final SessionFactory sessionFactory = buildSessionFactory();
private static SessionFactory buildSessionFactory(){
try {
return new Configuration().configure().buildSessionFactory();
}
catch (Throwable ex){
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory(){
return sessionFactory;
}
public static void shutdown(){
getSessionFactory().close();
}
}

管理数据.java

import org.hibernate.Session;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
public class ManageData {
public static void readFile() {
String line = "";
Session session = HibernateConfig.getSessionFactory().openSession();
try (BufferedReader br = new BufferedReader(new FileReader("/Users/ggabrychowicz/IdeaProjects/Bus Managing System/src/main/java/sample.csv"))){
while ((line = br.readLine()) != null){
String[] tempArr = line.split(",");
UserData userData = new UserData();

userData.setFirstName(tempArr[1]);
userData.setLastName(tempArr[2]);
userData.setTelephoneNo(Integer.parseInt(tempArr[3]));
userData.setEmail(tempArr[4]);
userData.setPickUp(tempArr[5]);
userData.setDropOff(tempArr[6]);
session.beginTransaction();
session.save(userData);
session.getTransaction().commit();
}
session.close();
}
catch (IOException e) {
if (session!=null){
session.getTransaction().rollback();
}
e.printStackTrace();
}
}
}

堆叠轨道：

Mar 25, 2020 11:20:43 AM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.4.10.Final}
Mar 25, 2020 11:20:43 AM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
Mar 25, 2020 11:20:43 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Mar 25, 2020 11:20:43 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/users]
Mar 25, 2020 11:20:43 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {password=****, user=root}
Mar 25, 2020 11:20:43 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
Mar 25, 2020 11:20:43 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
Wed Mar 25 11:20:43 CET 2020 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
Mar 25, 2020 11:20:44 AM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect
Mar 25, 2020 11:20:44 AM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@423b2b62] 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.
Mar 25, 2020 11:20:44 AM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "
create table users (
firstName varchar(255) not null auto_increment,
dropOff varchar(255),
email varchar(255),
lastName varchar(255),
pickUp varchar(255),
telephoneNo integer,
primary key (firstName)
) engine=MyISAM" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "
create table users (
firstName varchar(255) not null auto_increment,
dropOff varchar(255),
email varchar(255),
lastName varchar(255),
pickUp varchar(255),
telephoneNo integer,
primary key (firstName)
) engine=MyISAM" 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:559)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.createTable(AbstractSchemaMigrator.java:277)
at org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:71)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:207)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:320)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:462)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)
at HibernateConfig.buildSessionFactory(HibernateConfig.java:12)
at HibernateConfig.<clinit>(HibernateConfig.java:7)
at ManageData.readFile(ManageData.java:14)
at Main.main(Main.java:4)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Incorrect column specifier for column 'firstName'
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.Util.getInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:944)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3933)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3869)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2524)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2675)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2465)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2439)
at com.mysql.jdbc.StatementImpl.executeInternal(StatementImpl.java:829)
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:729)
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54)
... 16 more
Hibernate: 
create table users (
firstName varchar(255) not null auto_increment,
dropOff varchar(255),
email varchar(255),
lastName varchar(255),
pickUp varchar(255),
telephoneNo integer,
primary key (firstName)
) engine=MyISAM
Mar 25, 2020 11:20:44 AM org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformInitiator initiateService
INFO: HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
Exception in thread "main" java.lang.NumberFormatException: For input string: "Colepio"
at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:68)
at java.base/java.lang.Integer.parseInt(Integer.java:658)
at java.base/java.lang.Integer.parseInt(Integer.java:776)
at ManageData.readFile(ManageData.java:27)
at Main.main(Main.java:4)
Process finished with exit code 1

Answer 1

异常是：

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: 
Incorrect column specifier for column 'firstName'

这是因为它试图添加具有auto_increment的列firstName。auto_increment不适用于VARCHAR列。

在你的代码中你有：

@Id 
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column
private String firstName;

我假设您忘记了id属性，它应该看起来像：

@Id 
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
@Column
private String firstName;

Answer 2

检查application.properties 下是否使用了正确的方言

在application.properties.中使用spring.jpa.database-platform = org.hibernate.dialect.MySQL5Dialect