处理 BLOB 字段时如何提高 EclipseLink 的性能？

Question

由于每个实体都有 BLOB 字段，我的 Java 应用程序变得非常慢。该字段通常用于存储 PDF 文件，每当我必须列出所有对象时，持久性提供程序完成其工作需要花费大量时间。我寻找有关如何处理此类数据的答案，但其中一些人谈论将 BLOB 存储在单独的 table 中，然后使用 FetchType.LAZY。有没有办法只在需要时获取此字段而无需创建另一个 table？如果不是，创建另一个 table 是最合适的解决方案吗？

实体代码

@Cache(alwaysRefresh = true)
public class ScdDocumento implements Serializable, MultipleSelector {
    @Transient
    public static final String QUERY_RELATORIO_DOC_LOC = "consultas/ctrl_docs/consulta_relatorio_doc_local.txt";

    @Transient
    public static final String QUERY_RELATORIO_DOC_GRUPO = "consultas/ctrl_docs/consulta_relatorio_doc_grupo.txt";

    @Id
    @Column(name = "nome", length = 50)
    private String nome;

    @Column(name = "revisao")
    private int revisao;

    @Column(name = "id_tipo")
    private int id_tipo;

    @Column(name = "situacao", length = 1)
    private String situacao;

    @Column(name = "doc_blob_nome", length = 50)
    private String doc_blob_nome;

    @Lob 
    @Basic(fetch = FetchType.LAZY)
    @Column(name = "documento_blob", nullable = false)
    private byte[] documento_blob; //The field that impacts the application perfomance

    @Column(name = "abrangencia_geral")
    private int abrangencia_geral;

    @ManyToMany
    @JoinTable(name = "SCD_DOC_GRUPO", joinColumns = {@JoinColumn(name = "id_doc")},
        inverseJoinColumns = {@JoinColumn(name = "id_grupo")})
    private Set<SosGrupo> grupos;

    @ManyToOne
    @JoinColumn(name = "id_tipo", insertable = false, updatable = false)
    private ScdTipo tipo;

    @ManyToMany
    @JoinTable(name = "SCD_REFERENCIA", joinColumns = {@JoinColumn(name = "doc_pai")},
        inverseJoinColumns = {@JoinColumn(name = "doc_filho")})
    private Set<ScdDocumento> referencias;

    @ManyToMany
    @JoinTable(name = "SCD_REFERENCIA", joinColumns = {@JoinColumn(name = "doc_filho")},
        inverseJoinColumns = {@JoinColumn(name = "doc_pai")})
    private Set<ScdDocumento> referenciadoPor;

    @ManyToMany
    @JoinTable(name = "SCD_PALAVRA_REFERENCIA", joinColumns = {@JoinColumn(name = "documento")},
        inverseJoinColumns = {@JoinColumn(name = "palavra")})
    private Set<ScdPalavraChave> palavrasChaves;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "documento")
    private Set<ScdOrdem> ordens;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "documento")
    private Set<ScdArquivoOs> arquivosOs;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "documento")
    private Set<ScdArquivoHistorico> arquivosHistorico;

    @ManyToMany(cascade = {CascadeType.REFRESH, CascadeType.MERGE})
    @JoinTable(name = "SCD_LOCAL_DOC", joinColumns = {@JoinColumn(name = "id_doc")},
        inverseJoinColumns = {@JoinColumn(name = "id_local")})
    private Set<ScdLocal> locais;

    @Override
    public String getNome() {
        return nome;
    }

    public void setNome(String nome) {
        this.nome = nome;
    }

    public int getRevisao() {
        return revisao;
    }

    public void setRevisao(int revisao) {
        this.revisao = revisao;
    }

    public int getIdTipo() {
        return id_tipo;
    }

    public void setIdTipo(int id_tipo) {
        this.id_tipo = id_tipo;
    }

    public String getSituacao() {
        return situacao;
    }

    public void setSituacao(String situacao) {
        this.situacao = situacao;
    }

    public String getDocBlobNome() {
        return doc_blob_nome;
    }

    public void setDocBlobNome(String doc_blob_nome) {
        this.doc_blob_nome = doc_blob_nome;
    }

    public byte[] getDocumentoBlob() {
        return documento_blob;
    }

    public void setDocumentoBlob(byte[] documento_blob) {
        this.documento_blob = documento_blob;
    }

    public int getAbrangenciaGeral() {
        return abrangencia_geral;
    }

    public void setAbrangenciaGeral(int abrangencia_geral) {
        this.abrangencia_geral = abrangencia_geral;
    }

    public Set<SosGrupo> getGrupos() {
        return grupos;
    }

    public void setGrupos(Set<SosGrupo> grupo) {
        this.grupos = grupo;
    }

    public ScdTipo getTipo() {
        return tipo;
    }

    public void setTipo(ScdTipo tipo) {
        this.tipo = tipo;
    }

    public Set<ScdDocumento> getReferencias() {
        return referencias;
    }

    public void setReferencias(Set<ScdDocumento> referencias) {
        this.referencias = referencias;
    }

    public Set<ScdDocumento> getReferenciadoPor() {
        return referenciadoPor;
    }

    public void setReferenciadoPor(Set<ScdDocumento> referenciadoPor) {
        this.referenciadoPor = referenciadoPor;
    }

    public Set<ScdPalavraChave> getPalavrasChaves() {
        return palavrasChaves;
    }

    public void setPalavrasChaves(Set<ScdPalavraChave> palavrasChaves) {
        this.palavrasChaves = palavrasChaves;
    }

    public Set<ScdOrdem> getOrdens() {
        return ordens;
    }

    public void setOrdens(Set<ScdOrdem> ordens) {
        this.ordens = ordens;
    }

    public Set<ScdArquivoOs> getArquivosOs() {
        return arquivosOs;
    }

    public void setArquivosOs(Set<ScdArquivoOs> arquivosOs) {
        this.arquivosOs = arquivosOs;
    }

    public Set<ScdArquivoHistorico> getArquivosHistorico() {
        return arquivosHistorico;
    }

    public void setArquivosHistorico(Set<ScdArquivoHistorico> arquivosHistorico) {
        this.arquivosHistorico = arquivosHistorico;
    }

    public Set<ScdLocal> getLocais() {
        return locais;
    }

    public void setLocais(Set<ScdLocal> locais) {
        this.locais = locais;
    }    

    @Override
    public String getIdRef() {
        return nome;
    }

    @Override
    public String getDesc() {
        return tipo.getNome();
    }
}

导致问题的方法

图形界面

private void loadDocumentTable(String situacao) {
    mapaDocumentos = new TreeMap<>();
    modelDocumentos.setRowCount(0);

    docdao.getCriteria("situacao", situacao).forEach((e) -> {
        mapaDocumentos.put(e.getNome(), e);
    });

    mapaDocumentos.entrySet().forEach((e) -> {
        String desc = e.getValue().getDocBlobNome();
        modelDocumentos.addRow(new Object[]{e.getKey(), desc.substring(0, desc.length() - 3), e.getValue().getRevisao()});
    });
}

通用道

@Override
public List<T> getCriteria(String column, Object value){
    CriteriaBuilder cb = em.getCriteriaBuilder();
    CriteriaQuery<T> cq = cb.createQuery(clazz);
    Root<T> root = cq.from(clazz);
    EntityType<T> ent = root.getModel();
    cq.where(cb.equal(root.get(ent.getSingularAttribute(column)), value.toString()));

    return em.createQuery(cq).getResultList();
}

Table型号

坚持

将此添加到我的 persistence.xml，但 eclipselink 仍然急切地获取 byte[] 字段。

Maven 插件

         <plugin>
            <groupId>de.empulse.eclipselink</groupId>
            <artifactId>staticweave-maven-plugin</artifactId>
            <version>1.0.0</version>
            <executions>
                <execution>
                    <phase>process-classes</phase>
                    <goals>
                        <goal>weave</goal>
                    </goals>
                    <configuration>
                        <persistenceXMLLocation>META-INF/persistence.xml</persistenceXMLLocation>
                        <logLevel>FINE</logLevel>
                    </configuration>
                </execution>
            </executions>
            <dependencies>
               <dependency>
                   <groupId>org.eclipse.persistence</groupId>
                   <artifactId>org.eclipse.persistence.jpa</artifactId>
                   <version>2.5.2</version>
               </dependency>
            </dependencies>
        </plugin>

最终编辑

staticweave-maven-plugin 确实有效，但每次更改某些内容时我都需要构建项目以提高性能。发生这种情况是因为编织是静态的，所以它在构建时应用，而不是在运行项目使用 IDE.

时应用

Answer 1

JPAbasics also allow specifying a fetch type of LAZY, which would prevent loading the BLOB until you access it in the entity. OneToOne, ManyToOne and basic mappings require byte code enhancement of your entities for EclipseLink to gain notification when you access a lazy attribute and load it, which is described here as weaving。这将确保默认情况下不加载它。

通过编织，您还可以使用entity graphs to specify what is loaded and when. This can allow loading the blob in a single query with the rest of the entity when it is to be used, and exclude it by default elsewhere. See 获取有关加载和获取图表的信息。

处理 BLOB 字段时如何提高 EclipseLink 的性能？

How to increase performance in EclipseLink when dealing with BLOB fields?

java

jpa

eclipselink

oracle11g