如何将iTextPDF文档转换为字节数组

我需要在内存中创建后将iTextPDF Document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列中得到null值。

这是我的Document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，它运行得很好。 但是，当我尝试将其作为Stream返回时，我会得到一个空值。

问题是，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，只需获取字节并按照您的意愿处理它们。

  byte[] pdfBytes = byteArrayOutputStream.toByteArray(); 

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

希望这可以帮助。

Answer 2

从评论看来，它与在运行时生成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 {} 

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;