java byte[]Blob转

一、byte[]=>Blob

我们可以通过Hibernate提供的表态方法来实现如：

Hibernate.createBlob(new byte[1024]);

二、Blob=>byte[]

目前没有找到好一点的API提供，所以只能自已来实现。示例如下：

/**
* 把Blob类型转换为byte数组类型
* @param blob
* @return
*/
private byte[] blobToBytes(Blob blob) {

BufferedInputStream is = null;

try {
is = new BufferedInputStream(blob.getBinaryStream());
byte[] bytes = new byte[(int) blob.length()];
int len = bytes.length;
int offset = 0;
int read = 0;

while (offset < len && (read = is.read(bytes, offset, len - offset)) >= 0) {
offset += read;
}
return bytes;
} catch (Exception e) {
return null;
} finally {
try {
is.close();
is = null;
} catch (IOException e) {
return null;
}
}
}

三、InputStream=>byte[]

private byte[] InputStreamToByte(InputStream is) throws IOException {  

ByteArrayOutputStream bytestream = new ByteArrayOutputStream();  
int ch;  
while ((ch = is.read()) != -1) {  
bytestream.write(ch);  
}  
byte imgdata[] = bytestream.toByteArray();  
bytestream.close();  

return imgdata;  
}  

四、byte[] => InputStream

byte[]到inputStream之间的转换很简单：InputStream is = new ByteArrayInputStream(new byte[1024]);  

五、InputStream => Blob

可通过Hibernate提供的API：Hibernate.createBlob(new FileInputStream(" 可以为图片/文件等路径 "));

六、Blob => InputStream

Blog转流，可通过提供的API直接调用：new Blob().getBinaryStream();

七、用byte[]读取word文件内容方法

public byte[] getBytesFromFile(String filePath) throws IOException {
  File file = new File(filePath);
  InputStream is = new FileInputStream(file);
  long length = file.length();
  if (length > Integer.MAX_VALUE) {
  }
  byte[] bytes = new byte[(int) length];
  int offset = 0;
  int numRead = 0;
  while (offset < bytes.length
    && (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
   offset += numRead;
  }
  if (offset < bytes.length) {
   throw new IOException("Could   not   completely   read   file  ! "
     + file.getName());
  }

  is.close();
  return bytes;
 }