Question

我正在使用hibernate中的序列，我们有一个关于序列命名的命名约束格式是SEQ_。如何自定义/参数化SequenceStyleGenerator类以便在序列名称中添加前缀？

Answer 1

我最后创建了一个继承自SequenceStyleGenerator的类，并覆盖determineSequenceName函数以获得前缀。

public class PrefixSequenceStyleGenerator extends SequenceStyleGenerator {
public static final String CONFIG_PREFER_PREFIX = "prefer_sequence_prefix";
public static final String CONFIG_SEQUENCE_PER_ENTITY_PREFIX = "sequence_per_entity_prefix";
public static final String DEF_SEQUENCE_PREFIX = "SEQ_";

@Override
protected String determineSequenceName(Properties params, Dialect dialect) {
    boolean usePrefix = ConfigurationHelper.getBoolean(CONFIG_PREFER_PREFIX, params, false);
    if(usePrefix){
        final String sequencePerEntityPrefix = ConfigurationHelper.getString( CONFIG_SEQUENCE_PER_ENTITY_PREFIX, params, DEF_SEQUENCE_PREFIX );
        String sequenceName = ConfigurationHelper.getBoolean( CONFIG_PREFER_SEQUENCE_PER_ENTITY, params, false ) ? sequencePerEntityPrefix + params.getProperty( JPA_ENTITY_NAME ) : DEF_SEQUENCE_NAME;
        final ObjectNameNormalizer normalizer = (ObjectNameNormalizer) params.get( IDENTIFIER_NORMALIZER );
        sequenceName = ConfigurationHelper.getString( SEQUENCE_PARAM, params, sequenceName );
        if ( sequenceName.indexOf( '.' ) < 0 ) {
            sequenceName = normalizer.normalizeIdentifierQuoting( sequenceName );
            final String schemaName = params.getProperty( SCHEMA );
            final String catalogName = params.getProperty( CATALOG );
            sequenceName = Table.qualify(
                    dialect.quote( catalogName ),
                    dialect.quote( schemaName ),
                    dialect.quote( sequenceName )
                    );
            }
        return sequenceName;
    }else{
        return super.determineSequenceName(params, dialect);
    }
}

}

我在我的超级课程中使用它：

@MappedSuperclass

public class AbstractModelWithTableSequence实现AbstractModelInterface {

private static final long serialVersionUID = 6503670320979543539L;

@Id
@Column(name="id")
@GenericGenerator(name = "seq_generator", 
strategy = "com.gms.utils.PrefixSequenceStyleGenerator",
parameters = {
        @org.hibernate.annotations.Parameter(
                name = "optimizer", value = "pooled-lo"),
        @org.hibernate.annotations.Parameter(
                name = "initial_value", value = "1"),
        @org.hibernate.annotations.Parameter(
                name = "increment_size", value = "1"),
        @org.hibernate.annotations.Parameter(
                name = PrefixSequenceStyleGenerator.CONFIG_PREFER_SEQUENCE_PER_ENTITY, value = "true"),
        @org.hibernate.annotations.Parameter(
                name = PrefixSequenceStyleGenerator.CONFIG_SEQUENCE_PER_ENTITY_PREFIX, value = "SEQ_"),
        @org.hibernate.annotations.Parameter(
                name = PrefixSequenceStyleGenerator.CONFIG_PREFER_PREFIX, value = "true"),
    }
)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "seq_generator")
private Long id;

@Override
public Long getId() {
    return id;
}

@Override
public void setId(Long id) {
    this.id = id;
}

@Override
public boolean isNew() {
    return getId() == null || getId() == 0;
}

@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((id == null) ? 0 : id.hashCode());
    return result;
}

@Override
public boolean equals(Object obj) {
    if (this == obj) {
        return true;
    }
    if (obj == null) {
        return false;
    }
    if (getClass() != obj.getClass()) {
        return false;
    }
    AbstractModelWithTableSequence other = (AbstractModelWithTableSequence) obj;
    if (id == null) {
        if (other.id != null) {
            return false;
        }
    } else if (!id.equals(other.id)) {
        return false;
    }
    return true;
}

}

SequenceStyleGenerator，如何使用prefix而不是suffixe

1 个答案: