Question

在内存中创建后，我需要将 iTextPDF文档文件转换为 byte [] 。我已经测试过，我没有正确创建PDF的问题。问题是如何将其转换为字节数组以存储在DB中。

这是我的代码：

Document generatedDocument = reportService.generateRequestForm(scdUser, jsonObject, 0, null);
reportService.generateRequestForm(scdUser, jsonObject, 0, null);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PdfWriter pdfWriter = PdfWriter.getInstance(generatedDocument, baos);
generatedDocument.open();
document.setDocument(baos.toByteArray()); // stores as blob

我在数据库 blob 列中获得了 null 的值。

这是我的文档域对象：

文档域对象

@Entity
@Table(name = "document")
public class Document implements java.io.Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "document_id", nullable = false)
    private int documentId;
    @Column(name = "document_name", nullable = false, length = 65535)
    private String documentName;
    @Column(name = "document_type", nullable = false)
    private int documentType;
    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "upload_date", nullable = false, length = 19)
    private Date uploadDate = new Date();
    @Column(name = "document", nullable = false)
    private byte[] document;    // BLOB COLUMN
    @Column(name = "document_size", nullable = false)
    private long documentSize;
    @Column(name = "title", nullable = true, insertable = true, updatable = true, length = 65535, precision = 0)
    private String title;
    @Column(name = "tag", nullable = true, insertable = true, updatable = true, length = 65535, precision = 0)
    private String tag;
    @Column(name = "description", nullable = true, insertable = true, updatable = true, length = 65535, precision = 0)
    private String description;
    @Column(name = "shared", nullable = false, insertable = true, updatable = true, length = 1, precision = 0)
    private boolean shared = false;
    @Column(name = "status", nullable = false)
    private int status = DocumentStatus.READY.getStatus();


    public int getDocumentId() {
        return this.documentId;
    }

    public void setDocumentId(int documentId) {
        this.documentId = documentId;
    }

    public String getDocumentName() {
        return this.documentName;
    }

    public void setDocumentName(String documentName) {
        this.documentName = documentName;
    }

    public int getDocumentType() {
        return this.documentType;
    }

    public void setDocumentType(int documentType) {
        this.documentType = documentType;
    }

    public Date getUploadDate() {
        return this.uploadDate;
    }

    public void setUploadDate(Date uploadDate) {
        this.uploadDate = uploadDate;
    }

    public byte[] getDocument() {
        return this.document;
    }

    public void setDocument(byte[] document) {
        this.document = document;
    }

    public long getDocumentSize() {
        return this.documentSize;
    }

    public void setDocumentSize(long documentSize) {
        this.documentSize = documentSize;
    }

    public String getTag() {
        return tag;
    }

    public void setTag(String tag) {
        this.tag = tag;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public boolean getShared() {
        return shared;
    }

    public void setShared(boolean shared) {
        this.shared = shared;
    }


    public int getStatus() {
        return status;
    }

    public void setStatus(int status) {
        this.status = status;
    }


}

Answer 1

我遇到了类似的问题......我创建了Document并在我创建它的类中，我可以将它保存到File，它工作得很好。但是，当我尝试将其作为Stream返回时，我会得到一个空值。

问题在于，一旦文档关闭（document.close（）），它也会关闭Stream。

解决方法是在创建Document并创建PdfWriter输出时创建ByteArrayOutputStream。然后，我可以用PDF字节做任何我想做的事情...在我的情况下，我将它们转换为StreamedContent以发送给用户。

创建一个变量来保存字节：

  private ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

让PdfWriter在创建文档时将数据输出到byte []：

  Document document = new Document(PageSize.LETTER, 0.75F, 0.75F, 0.75F, 0.75F);
  PdfWriter.getInstance(document, byteArrayOutputStream);  // Do this BEFORE document.open()

  document.open();
  createPDF(document);  // Whatever function that you use to create your PDF
  document.close();

完成生成PDF后，只需获取字节，然后按照自己的意愿进行操作。

  byte[] pdfBytes = byteArrayOutputStream.toByteArray();

我不知道你的reportService类是什么样的，但这可能是一个放置它的好地方。

希望这有帮助。

Answer 2

从评论中可以看出，它与运行时生成PDF的方式无关，而是与存储在数据库中的方式无关。您还需要提供该代码。

这是我实际上（我的测试）：

持有人：

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;



@Entity
public class PDFHolder implements Serializable {

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private long id;

@Column(columnDefinition = "LONGBLOB")
private byte[] documentPDF;

public byte[] getDocumentPDF() {
    return documentPDF;
}

public void setDocumentPDF(byte[] documentPDF) {
    this.documentPDF = documentPDF;
}

public long getId() {
    return id;
}

public void setId(long id) {
    this.id = id;
}
}

存储库，执行保存：

@Repository
public interface PDFHolderRepository extends JpaRepository<PDFHolder, Long> {}

实际插入：

private void generateDatabaseRows() {

    try{
        String urlPDF = "http://cetatenie.just.ro/LinkClick.aspx?fileticket=K13DZkoIE2o%3d&tabid=57&mid=593";
        URL url = new URL(urlPDF);

        ByteBuffer byteBufferResponse = this.getAsByteArray(url.openConnection());
        byte [] responseArray = byteBufferResponse.array();
        System.out.println("Size of the PDF : " + responseArray.length);

        // Save it to DB
        PDFHolder pdfHolder = new PDFHolder();
        pdfHolder.setDocumentPDF(responseArray);

        pdfHolderRepository.save(pdfHolder);

    } catch(Exception e){
        e.printStackTrace();
    }
}


private ByteBuffer getAsByteArray(final URLConnection urlConnection) throws IOException {
    final ByteArrayOutputStream tmpOut = new ByteArrayOutputStream();
    final InputStream inputStream = urlConnection.getInputStream();
    final byte[] buf = new byte[1024];
    int len;
    while (true) {
        len = inputStream.read(buf);
        if (len == -1) {
            break;
        }
        tmpOut.write(buf, 0, len);
    }
    tmpOut.close();
    return ByteBuffer.wrap(tmpOut.toByteArray(), 0, tmpOut.size());
}

当然，我在这个类中有一个@Autowired存储库：

@Autowired
PDFHolderRepository pdfHolderRepository;

MySQL stores the byte array

Answer 3

刚刚更新了 iText 7 版本的答案。

private static byte[] createPDF() {
    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    PdfWriter writer = new PdfWriter(byteArrayOutputStream);
    PdfDocument pdfDocument = new PdfDocument(writer);
    Document document = new Document(pdfDocument);

    //Write the file content

    document.close();
    return byteArrayOutputStream.toByteArray();
}

如何将iTextPDF文档转换为字节数组

3 个答案: