Hibernate 5 隐式命名策略

Question

我想使用休眠 5.x。在 hibernate 5.x 中，有新的接口ImplicitNamingStrategy和PhysicalNamingStrategy。

对于name实体的属性，User我希望user_name在我的数据库中有一个列名。我不想用@Column(name="..."). 我尝试编写自定义，ImplicitNamingStrategy但无法获取拥有实体的名称。

public class MyNamingStrategy extends ImplicitNamingStrategyComponentPathImpl
{
    @Override
    public Identifier determineBasicColumnName ( ImplicitBasicColumnNameSource source )
    {
        // How to get the name of the owning entity?
        String owningEntityName = "howdoigetthis"; 
        Identifier basicColumnName = super.determineBasicColumnName(source);
        Identifier identifier = Identifier.toIdentifier(owningEntityName +"_" + basicColumnName.toString());
        return identifier;
    }
}

有没有办法只使用 NamingStrategy 来为每一列添加表（或实体）名称的前缀？

Answer 1

如果您不介意一点肮脏的反射，这里有一个解决方案：

@Override
public Identifier determineBasicColumnName(final ImplicitBasicColumnNameSource source)
{
    // Get 'this$0' field and make it accessible
    Field ejb3ColumnField = null;
    final Field[] sourceFields = source.getClass().getDeclaredFields();
    for (final Field sourceField : sourceFields) {
        if (sourceField.getName().equals("this$0")) {
            ejb3ColumnField = sourceField;
        }
    }
    ejb3ColumnField.setAccessible(true);

    // Get actual field object
    String owningEntityName;
    Ejb3Column ejb3Column;
    try {
        ejb3Column = (Ejb3Column) ejb3ColumnField.get(source);
    } catch (
        IllegalArgumentException
        | IllegalAccessException e) {
        throw new RuntimeException(e);  // (Or deal with this appropriately, e.g. log it.)
    }

    // The property holder path holds the owning entity's fully qualified name
    final String owningEntityFullyQualifiedName = ejb3Column.getPropertyHolder().getPath();

    // The entity name is after the last dot in the fully qualified name
    final String[] owningEntityTokens = owningEntityFullyQualifiedName.split("\\.");
    owningEntityName = owningEntityTokens[owningEntityTokens.length - 1];

    final Identifier basicColumnName = super.determineBasicColumnName(source);
    return Identifier.toIdentifier(owningEntityName + "_" + basicColumnName.toString());
}