ImprovedNamingStrategy 不再适用于 Hibernate 5

Question

我有简单的 spring-jpa 配置，其中配置了 Hibernate 的 ImprovedNamingStrategy。这意味着如果我的实体 class 有一个变量 userName，那么 Hibernate 应该将它转换为 user_name 以便查询数据库。但是在我升级到 Hibernate 5 之后，这个命名转换停止工作了。我收到错误：

ERROR: Unknown column 'user0_.userName' in 'field list'

这是我的 Hibernate 配置：

@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();
    }
}

这是我的实体 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;

}

我不想在@Column 注释中明确命名我的数据库字段。我想要我的配置可以隐式地将驼峰大小写转换为下划线。

请指导。

Answer 1

刚刚解决了这个问题，当使用 Hibernate 版本 < 5.0 时配置绝对没问题，但 Hibernate >= 5.0 则不行。

我使用的是 Hibernate 5.0.0.Final 和 Spring 4.2.0.RELEASE。我猜 Hibernate 5 与 Spring 4.2 不完全兼容。我刚刚将 Hibernate 降级到 4.2.1.Final 并且一切正常。

Hibernate 的 NamingStrategy class 在 Hibernate 5 中已弃用。

Answer 2

感谢您发布自己的解决方案。设置 Hibernate 5 命名策略对我帮助很大！

pre-Hibernate 5.0 的 hibernate.ejb.naming_strategy 属性似乎分为两部分：

hibernate.physical_naming_strategy
hibernate.implicit_naming_strategy

这些属性的值没有像 hibernate.ejb.naming_strategy 那样实现 NamingStrategy 接口。有两个用于这些目的的新界面：

org.hibernate.boot.model.naming.PhysicalNamingStrategy
org.hibernate.boot.model.naming.ImplicitNamingStrategy

Hibernate 5 仅提供了一种 PhysicalNamingStrategy (PhysicalNamingStrategyStandardImpl) 的实现，它假定物理标识符名称与逻辑名称相同。

ImplicitNamingStrategy 有多种实现，但我发现 none 等同于旧的 ImprovedNamingStrategy。（参见：org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyHbmImpl）

所以，我实现了自己的 PhysicalNamingStrategy，这非常简单：

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);
 }
}

请注意，addUnderscores() 方法来自原始 org.hibernate.cfg.ImprovedNamingStrategy。

然后，我将这个物理策略设置到 persistence.xml 文件中：

  <property name="hibernate.physical_naming_strategy" value="my.package.PhysicalNamingStrategyImpl" />

将Hibernate 5命名策略设置为以前的版本设置是一个陷阱。

Answer 3

希望这对您有所帮助：

hibernate.implicit_naming_strategy=....隐式命名策略 hibernate.physical_naming_strategy=....PhysicalNamingStrategyImpl

这是代码（只是从现有代码重新排列）：

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);
    }

}

Answer 4

感谢并 +1 Samuel Andrés 的非常有用的答案，但是避免手写蛇套逻辑可能是个好主意。这是相同的解决方案，使用番石榴。

它假定您的实体名称写在 StandardJavaClassFormat 中，列名写在 standardJavaFieldFormat

中

希望这会节省一些将来来这里的人一些谷歌搜索:-)

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()
    );
  }
}

Answer 5

感谢 post。升级会破坏 table 和列名策略，这有点让人恼火。除了从 ImprovedNamingStrategy 复制逻辑，您还可以使用委托。

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);
    }
}

Answer 6

没有 Guava 和 Apache 实用程序

public class PhysicalNamingStrategyImpl extends PhysicalNamingStrategyStandardImpl {

    public Identifier toPhysicalTableName(Identifier name, JdbcEnvironment context) {
        return context.getIdentifierHelper().toIdentifier(
                name.getText().replaceAll("((?!^)[^_])([A-Z])", "_").toLowerCase(),
                name.isQuoted()
        );
    }

    public Identifier toPhysicalColumnName(Identifier name, JdbcEnvironment context) {
        return context.getIdentifierHelper().toIdentifier(
                name.getText().replaceAll("((?!^)[^_])([A-Z])", "_").toLowerCase(),
                name.isQuoted()
        );
    }
}

Answer 7

每个答案都通过实施 PhysicalNamingStrategy 来发布解决方案，但您需要（并且应该做的）就是实施 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.

代码可以像这样简单（使用其他答案中的原始 addUnderscores）：

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);
    }
}

Answer 8

而不是

jpaProperties.put("hibernate.ejb.naming_strategy",
                  "org.hibernate.cfg.ImprovedNamingStrategy");

更改为新的物理命名策略和新的实现 CamelCaseToUnderscoresNamingStrategy，其行为与旧的 ImprovedNamingStrategy:

jpaProperties.put("hibernate.physical_naming_strategy",
                  "org.hibernate.boot.model.naming.CamelCaseToUnderscoresNamingStrategy");

在 Hibernate 5.6 中可用。1.FINAL

ImprovedNamingStrategy 不再适用于 Hibernate 5

ImprovedNamingStrategy no longer working in Hibernate 5

java

hibernate

jpa

spring-data-jpa

hibernate-5.x