Question

我正在尝试使用hibernate，jsf和mysql将.doc，.pdf，.txt和图像文件保存到我的数据库中。

我创建了一个列来保存BLOB类型的文件。如果我保存.txt类型，则文件会正确保存。

如果我试图保存任何其他格式的文件，那么我得到一个例外。在我的bean中，我创建了一个字段名称：byte[] file;

如何正确保存，没有任何例外？我是否需要更改mysql列的数据类型或为java类使用不同的字段？

（回应BalusC）

这是我用于文件编写的代码。我正在使用fileInputStream，然后使用hibernate框架保存文件。

Iterator iter = items.iterator();
while (iter.hasNext()) {
FileItem item = (FileItem) iter.next();

if (item.isFormField()) {
   String name = item.getFieldName();
   String value = item.getString();
} else {
   String fieldName = item.getFieldName();
   String fileName = item.getName();
   String contentType = item.getContentType();
   boolean isInMemory = item.isInMemory();
   long sizeInBytes = item.getSize();
   byte[] fileInBytes=item.get();


   try {
      File uploadedFile = new File("/home/db/webApp", fileName);
      uploadedFile.createNewFile();
      FileInputStream fileInputStream = new FileInputStream(uploadedFile);
      //convert file into array of bytes
      fileInputStream.read(fileInBytes);
      fileInputStream.close();
  } catch (Exception e) {
      e.printStackTrace();
  }

   UploadedFile object= new UploadedFile(); 
   object.setFile(fileInBytes);
   uploadedObject.setFileName(fileName);
   session.save(object);

UploadedFile是jsf托管bean：

public class UploadedFile{
   private String fileName;
   private byte[] file;
   /**
    * @return the fileName
    */
   public String getFileName() {
      return fileName;
   }
   /**
    * @param fileName the fileName to set
    */
   public void setFileName(String fileName) {   
      this.fileName = fileName;
   }
   /**
    * @return the file
    */
  public byte[] getFile() {
     return file;
  }
  /**
   * @param file the file to set
   */
  public void setFile(byte[] file) {
      this.file = file;
   }
}

我的数据库表有以下结构：

Create UploadFile(FILE_NAME` VARCHAR(1000) NOT NULL,
 `FILE` BLOB NOT NULL);

Answer 1

最好将文件保存在某个位置并保存数据库中的位置

Answer 2

您的问题看起来像是数据类型问题。 MySQL中的BLOB不是很大。尝试将表的列数据类型设置为LONGBLOB。

Answer 3

将文件元信息（例如位置）存储在db中，但同步db和文件系统将是一个问题。

Answer 4

package com.server;


import java.io.*;

import java.sql.*;
import java.util.*;
import java.text.*;
import java.util.regex.*;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.*;
import org.mortbay.jetty.Response;

import javax.servlet.*;
import javax.servlet.http.*;

import java.io.*;   
import java.sql.*;   
import javax.servlet.http.HttpServlet;   
import javax.servlet.http.HttpServletRequest;   
import javax.servlet.http.HttpServletResponse;   
import javax.servlet.ServletInputStream.*;   
import java.io.PrintWriter;   

public class XmlServlet extends HttpServlet {   

public void doPost(HttpServletRequest req,HttpServletResponse res)   
{ 
    File uploadedFile;


    System.out.print("on server");
try{   

Class.forName("com.mysql.jdbc.Driver");   
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3308/image","root","root1");  

PrintWriter out=res.getWriter();   

//out.println("<br>Content type is :: " +contentType);   
//to get the content type information from JSP Request Header   
String contentType = req.getContentType();   
int flag=0;   
FileInputStream fis=null;   
FileOutputStream fileOut=null;   
//here we are checking the content type is not equal to Null and as well as the passed data from mulitpart/form-data is greater than or equal to 0   
if ((contentType != null) && (contentType.indexOf("multipart/form-data") >= 0))   
{   
DataInputStream in = new DataInputStream(req.getInputStream());   
//we are taking the length of Content type data   
int formDataLength = req.getContentLength();   
byte dataBytes[] = new byte[formDataLength];   
int byteRead = 0;   
int totalBytesRead = 0;   

//this loop converting the uploaded file into byte code   
while (totalBytesRead < formDataLength) {   
byteRead = in.read(dataBytes, totalBytesRead,formDataLength);   
totalBytesRead += byteRead;   
}   

String file = new String(dataBytes);   
//for saving the file name   
String saveFile = file.substring(file.indexOf("filename=\"") + 10);   
saveFile = saveFile.substring(0, saveFile.indexOf("\n"));   
out.println("savefiledddd"+saveFile);   
int extension_save=saveFile.lastIndexOf("\"");   
String extension_saveName=saveFile.substring(extension_save);   

//Here we are invoking the absolute path out of the encrypted data   

saveFile = saveFile.substring(saveFile.lastIndexOf("\\")+ 1,saveFile.indexOf("\""));   
int lastIndex = contentType.lastIndexOf("=");   
String boundary = contentType.substring(lastIndex + 1,contentType.length());   
int pos;   

//extracting the index of file   
pos = file.indexOf("filename=\"");   
pos = file.indexOf("\n", pos) + 1;   
pos = file.indexOf("\n", pos) + 1;   
pos = file.indexOf("\n", pos) + 1;   
int boundaryLocation = file.indexOf(boundary, pos) - 4;   
int startPos = ((file.substring(0, pos)).getBytes()).length;   
int endPos = ((file.substring(0, boundaryLocation)).getBytes()).length;   

out.println("savefile"+saveFile);   

int file_No=22;  

 uploadedFile=new File("./war/img");

    uploadedFile.mkdir();


  String kk=uploadedFile.getAbsolutePath();


  String pathname_dir=kk+"/"+saveFile;   
   //String pathname_dir="C:\\Program Files\\Apache Software Foundation\\Tomcat 6.0\\jk\\"+saveFile;   
    File filepath=new File(pathname_dir);   
     out.println("filepath_  "+filepath);   
    fileOut = new FileOutputStream(filepath);   
    fileOut.write(dataBytes, startPos, (endPos - startPos));   
    fileOut.flush();   
    out.println("<h1> your files are saved</h1></body></html>");   
     out.close();   

        File database_filename=new File(pathname_dir);   
            fis=new FileInputStream(database_filename);   

int len=(int)database_filename.length();
            PreparedStatement ps = conn.prepareStatement("insert into new (image) values (?)");   
            ps.setBinaryStream(1,fis,len);   
            ps.executeUpdate();   
            ps.close();   
            flag=1;   

}   

if(flag==1)   
{   
fileOut.close();   
fis.close();   
}   
}catch(Exception e)   
{   
System.out.println("Exception Due to"+e);   
e.printStackTrace();   
}   
}   
}

这是一个服务器代码。通过该代码，您可以上载存储在数据库中的任何文件，并将该文件存储在服务器端的（img）文件夹中。通过使用它的引用，您可以访问该文件。

如何使用java将doc，pdf和image文件保存到mysql数据库？

4 个答案: