什么是 JDBC Blob 数据类型？如何存储和读取其中的数据？

String mysqlUrl = "jdbc:mysql://localhost/sampleDB";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "passWord");

PreparedStatement pstmt = con.prepareStatement("INSERT INTO MyTableVALUES(?, ?)");

pstmt.setString(1, "sample image");
//Inserting Blob type
InputStream in = new FileInputStream("E:\images\cat.jpg");
pstmt.setBlob(2, in);

while(rs.next()) {
   rs.getString("Name");
   rs.getString("Type");
   Blob blob = rs.getBlob("LoGo");
}

byte byteArray[] = blob.getBytes(1,(int)blob.length());
FileOutputStream outPutStream = new FileOutputStream("path");
outPutStream.write(byteArray);

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
public class BlobExample {
   public static void main(String args[]) throws Exception {
      //ReGIStering the Driver
      DriverManager.registerDriver(new com.mysql.jdbc.Driver());
      //Getting the connection
      String mysqlUrl = "jdbc:mysql://localhost/sampleDB";
      Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
      System.out.println("Connection established......");
      //Creating a table
      Statement stmt = con.createStatement();
      stmt.execute("CREATE TABLE SampleTable( Name VARCHAR(255), Image BLOB)");
      System.out.println("Table Created");
      //Inserting values
      String query = "INSERT INTO SampleTable(Name,image) VALUES (?, ?)";
      PreparedStatement pstmt = con.prepareStatement(query);
      pstmt.setString(1, "sample image");
      FileInputStream fin = new FileInputStream("E:\images\cat.jpg");
      pstmt.setBlob(2, fin);
      pstmt.execute();
      //Retrieving the data
      ResultSet rs = stmt.executeQuery("select * from SampleTable");
      int i = 1;
      System.out.println("Contents of the table are: ");
      while(rs.next()) {
         System.out.println(rs.getString("Name"));
         Blob blob = rs.getBlob("Image");
         byte byteArray[] = blob.getBytes(1,(int)blob.length());
         FileOutputStream outPutStream = new
         FileOutputStream("E:\images\blob_output"+i+".jpg");
         outPutStream.write(byteArray);
         System.out.println("E:\images\blob_output"+i+".jpg");
         System.out.println();
         i++;
      }
   }
}

Connection established......
Table Created
Contents of the table are:
sample image
E:\images\blob_output1.jpg