问题
I have simple spring-jpa configuration where I have configured Hibernate's ImprovedNamingStrategy. This means if my entity class has a variable userName, then Hibernate should convert it to user_name for querying the database. But this naming conversion stopped working after I upgraded to Hibernate 5. I am getting the error:
ERROR: Unknown column 'user0_.userName' in 'field list'
This is my Hibernate config:
@Configuration
@EnableJpaRepositories("com.springJpa.repository")
@EnableTransactionManagement
public class DataConfig {
@Bean
public DataSource dataSource(){
DriverManagerDataSource ds = new DriverManagerDataSource();
ds.setDriverClassName("com.mysql.jdbc.Driver");
ds.setUrl("jdbc:mysql://localhost:3306/test");
ds.setUsername("root");
ds.setPassword("admin");
return ds;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory(){
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
vendorAdapter.setShowSql(Boolean.TRUE);
vendorAdapter.setDatabase(Database.MYSQL);
LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
factory.setJpaVendorAdapter(vendorAdapter);
factory.setDataSource(dataSource());
factory.setPackagesToScan("com.springJpa.entity");
Properties jpaProperties = new Properties();
jpaProperties.put("hibernate.ejb.naming_strategy","org.hibernate.cfg.ImprovedNamingStrategy");
jpaProperties.put("hibernate.dialect","org.hibernate.dialect.MySQL5InnoDBDialect");
factory.setJpaProperties(jpaProperties);
factory.afterPropertiesSet();
return factory;
}
@Bean
public SharedEntityManagerBean entityManager() {
SharedEntityManagerBean entityManager = new SharedEntityManagerBean();
entityManager.setEntityManagerFactory(entityManagerFactory().getObject());
return entityManager;
}
@Bean
public PlatformTransactionManager transactionManager() {
JpaTransactionManager txManager = new JpaTransactionManager();
txManager.setEntityManagerFactory(entityManagerFactory().getObject());
return txManager;
}
@Bean
public ImprovedNamingStrategy namingStrategy(){
return new ImprovedNamingStrategy();
}
}
This is my Entity class:
@Getter
@Setter
@Entity
@Table(name="user")
public class User{
@Id
@GeneratedValue
private Long id;
private String userName;
private String email;
private String password;
private String role;
}
I don't want to explicitly name my database fields within the @Column annotations. I want my configuration which can implicitly convert camel case to underscore.
Please guide.
回答1:
Thanks for posting your own solution. It helps me so much to set Hibernate 5 naming strategy!
The hibernate.ejb.naming_strategy property of pre-Hibernate 5.0 seems split into two parts:
hibernate.physical_naming_strategyhibernate.implicit_naming_strategy
The values of these properties do not implement the NamingStrategy interface as did hibernate.ejb.naming_strategy. There are two new interfaces for these purposes:
org.hibernate.boot.model.naming.PhysicalNamingStrategyorg.hibernate.boot.model.naming.ImplicitNamingStrategy
Hibernate 5 provides only one implementation of PhysicalNamingStrategy (PhysicalNamingStrategyStandardImpl) that assumes physical identifier names are the same as logical ones.
There are several implementations of ImplicitNamingStrategy but I found none equivalent to the old ImprovedNamingStrategy. (See: org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyHbmImpl)
So, I implemented my own PhysicalNamingStrategy which is very simple:
public class PhysicalNamingStrategyImpl extends PhysicalNamingStrategyStandardImpl implements Serializable {
public static final PhysicalNamingStrategyImpl INSTANCE = new PhysicalNamingStrategyImpl();
@Override
public Identifier toPhysicalTableName(Identifier name, JdbcEnvironment context) {
return new Identifier(addUnderscores(name.getText()), name.isQuoted());
}
@Override
public Identifier toPhysicalColumnName(Identifier name, JdbcEnvironment context) {
return new Identifier(addUnderscores(name.getText()), name.isQuoted());
}
protected static String addUnderscores(String name) {
final StringBuilder buf = new StringBuilder( name.replace('.', '_') );
for (int i=1; i<buf.length()-1; i++) {
if (
Character.isLowerCase( buf.charAt(i-1) ) &&
Character.isUpperCase( buf.charAt(i) ) &&
Character.isLowerCase( buf.charAt(i+1) )
) {
buf.insert(i++, '_');
}
}
return buf.toString().toLowerCase(Locale.ROOT);
}
}
Note that the addUnderscores() method is from the original org.hibernate.cfg.ImprovedNamingStrategy.
Then, I set this physical strategy into the persistence.xml file :
<property name="hibernate.physical_naming_strategy" value="my.package.PhysicalNamingStrategyImpl" />
It is a trap to set Hibernate 5 naming strategy as previous version settings.
回答2:
Thanks and +1 to Samuel Andrés for the very helpful answer, however it's probably a good idea to avoid the hand-written snake-casing logic. Here is the same solution, using Guava.
It assumes your entity names are written in the StandardJavaClassFormat and column names in the standardJavaFieldFormat
Hopefully this will save some people coming here in future some googling :-)
import org.hibernate.boot.model.naming.Identifier;
import org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl;
import org.hibernate.engine.jdbc.env.spi.JdbcEnvironment;
import static com.google.common.base.CaseFormat.*;
public class SnakeCaseNamingStrategy extends PhysicalNamingStrategyStandardImpl {
public Identifier toPhysicalTableName(Identifier name, JdbcEnvironment context) {
return new Identifier(
UPPER_CAMEL.to(LOWER_UNDERSCORE, name.getText()),
name.isQuoted()
);
}
public Identifier toPhysicalColumnName(Identifier name, JdbcEnvironment context) {
return new Identifier(
LOWER_CAMEL.to(LOWER_UNDERSCORE, name.getText()),
name.isQuoted()
);
}
}
回答3:
thanks for that post. Little anoying that upgrade breaks the table and column name strategy. Instead of copying the logic from ImprovedNamingStrategy you could also use delegation.
public class TableNamingStrategy extends PhysicalNamingStrategyStandardImpl {
private static final String TABLE_PREFIX = "APP_";
private static final long serialVersionUID = 1L;
private static final ImprovedNamingStrategy STRATEGY_INSTANCE = new ImprovedNamingStrategy();
@Override
public Identifier toPhysicalTableName(Identifier name, JdbcEnvironment context) {
return new Identifier(classToTableName(name.getText()), name.isQuoted());
}
@Override
public Identifier toPhysicalColumnName(Identifier name, JdbcEnvironment context) {
return new Identifier(STRATEGY_INSTANCE.classToTableName(name.getText()), name.isQuoted());
}
private String classToTableName(String className) {
return STRATEGY_INSTANCE.classToTableName(TABLE_PREFIX + className);
}
}
回答4:
Every answer posts solution by implementing PhysicalNamingStrategy, but all you need (and should do) is to implement ImplicitNamingStrategy.
When an entity does not explicitly name the database table that it maps to, we need to implicitly determine that table name. Or when a particular attribute does not explicitly name the database column that it maps to, we need to implicitly determine that column name. There are examples of the role of the org.hibernate.boot.model.naming.ImplicitNamingStrategy contract to determine a logical name when the mapping did not provide an explicit name.
And the code can be as easy as this (using the original addUnderscores as in other answers):
public class ImplicitNamingStrategyImpl extends ImplicitNamingStrategyJpaCompliantImpl {
@Override
protected Identifier toIdentifier(String stringForm, MetadataBuildingContext buildingContext) {
return super.toIdentifier(addUnderscores(stringForm), buildingContext);
}
protected static String addUnderscores(String name) {
final StringBuilder buf = new StringBuilder(name.replace('.', '_'));
for (int i = 1; i < buf.length() - 1; i++) {
if (Character.isLowerCase(buf.charAt(i - 1))
&& Character.isUpperCase(buf.charAt(i))
&& Character.isLowerCase(buf.charAt(i + 1))) {
buf.insert(i++, '_');
}
}
return buf.toString().toLowerCase(Locale.ROOT);
}
}
回答5:
hope this helps:
hibernate.implicit_naming_strategy=....ImplicitNamingStrategy hibernate.physical_naming_strategy=....PhysicalNamingStrategyImpl
and here is the code (just re-arrenged from existing code):
import java.io.Serializable;
import java.util.Locale;
import org.hibernate.boot.model.naming.Identifier;
import org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl;
import org.hibernate.engine.jdbc.env.spi.JdbcEnvironment;
public class PhysicalNamingStrategyImpl extends PhysicalNamingStrategyStandardImpl implements Serializable {
public static final PhysicalNamingStrategyImpl INSTANCE = new PhysicalNamingStrategyImpl();
@Override
public Identifier toPhysicalTableName(Identifier name, JdbcEnvironment context) {
return new Identifier(addUnderscores(name.getText()), name.isQuoted());
}
@Override
public Identifier toPhysicalColumnName(Identifier name, JdbcEnvironment context) {
return new Identifier(addUnderscores(name.getText()), name.isQuoted());
}
protected static String addUnderscores(String name) {
final StringBuilder buf = new StringBuilder( name.replace('.', '_') );
for (int i=1; i<buf.length()-1; i++) {
if (
Character.isLowerCase( buf.charAt(i-1) ) &&
Character.isUpperCase( buf.charAt(i) ) &&
Character.isLowerCase( buf.charAt(i+1) )
) {
buf.insert(i++, '_');
}
}
return buf.toString().toLowerCase(Locale.ROOT);
}
}
回答6:
No Guava and Apache utils
public class PhysicalNamingStrategyImpl extends PhysicalNamingStrategyStandardImpl {
public Identifier toPhysicalTableName(Identifier name, JdbcEnvironment context) {
return context.getIdentifierHelper().toIdentifier(
name.getText().replaceAll("((?!^)[^_])([A-Z])", "$1_$2").toLowerCase(),
name.isQuoted()
);
}
public Identifier toPhysicalColumnName(Identifier name, JdbcEnvironment context) {
return context.getIdentifierHelper().toIdentifier(
name.getText().replaceAll("((?!^)[^_])([A-Z])", "$1_$2").toLowerCase(),
name.isQuoted()
);
}
}
回答7:
Just figured out the issue, the configuration is absolutely fine when using a Hibernate version < 5.0 but not for Hibernate >= 5.0.
I was using Hibernate 5.0.0.Final with Spring 4.2.0.RELEASE. I guess the Hibernate 5 is not fully compatible with Spring 4.2 . I just downgraded Hibernate to 4.2.1.Final and things started working fine.
Hibernate's NamingStrategy class is deprecated in Hibernate 5.
来源：https://stackoverflow.com/questions/32437202/improvednamingstrategy-no-longer-working-in-hibernate-5