Retrieving BLOB Values with getBinaryStream() Method

This section describes how to retrieve BLOB values with the ResultSet.getBinaryStream() method.

BLOB values can also be retrieved with the getBinaryStream() method on the ResultSet object, which will return an OutputStream object. Then you can read the BLOB values from the OutputStream object with the read() method. The sample program below shows you how to create OutputStream objects with the getBinaryStream() method. A utility method is included to read all bytes from an OutputStream object and save them in a file.

/* MySqlBlobGetBinaryStream.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.io.*;
import java.sql.*;
public class MySqlBlobGetBinaryStream {
  public static void main(String [] args) {
    Connection con = null;
    try {
      com.mysql.cj.jdbc.MysqlDataSource ds
        = new com.mysql.cj.jdbc.MysqlDataSource();
      ds.setServerName("localhost");
      ds.setPortNumber(3306);
      ds.setDatabaseName("HerongDB");
      ds.setUser("Herong");
      ds.setPassword("TopSecret");
      con = ds.getConnection();

// Retrieving CLOB value with getBinaryStream()
      Statement sta = con.createStatement();
      ResultSet res = sta.executeQuery("SELECT * FROM Image");
      int i = 0;
      while (res.next() && i<3) {
        i++;
        System.out.println("Record ID: "+res.getInt("ID"));
        System.out.println("   Subject = "+res.getString("Subject"));
        InputStream bodyOut = res.getBinaryStream("Body");
        String fileOut = "BlobOut_"+res.getInt("ID")+".bin";
        saveOutputStream(fileOut,bodyOut);
        bodyOut.close();
        System.out.println("   Body = (Saved in "+fileOut+")");
      }
      res.close();

      sta.close();
      con.close();
    } catch (Exception e) {
      System.err.println("Exception: "+e.getMessage());
      e.printStackTrace();
    }
  }
  public static void saveOutputStream(String name, InputStream body) {
    int c;
    try {
      OutputStream f = new FileOutputStream(name);
      while ((c=body.read())>-1) {
        f.write(c);
      }
      f.close();
    } catch (Exception e) {
      System.err.println("Exception: "+e.getMessage());
      e.printStackTrace();
    }
  }
}

The output looked correct:

herong> java -cp .:mysql-connector-java-8.0.19.jar \
   MySqlBlobGetBinaryStream.java

Record ID: 1
   Subject = Test on INSERT statement
   Body = (Saved in BlobOut_1.bin)
Record ID: 2
   Subject = Test of the setBytes() method
   Body = (Saved in BlobOut_2.bin)
Record ID: 3
   Subject = Test of setBinaryStream() methods
   Body = (Saved in BlobOut_3.bin)

I also tested BlobOut_3.bin file to make sure that I am getting my MySqlBlobSetBinaryStream.class file back correctly:

herong> del MySqlBlobSetBinaryStream.class

herong> copy BlobOut_3.bin MySqlBlobSetBinaryStream.class
        1 file(s) copied.

herong> java -cp .:mysql-connector-java-8.0.19.jar \
   MySqlBlobSetBinaryStream

The inserted record:
   Subject = Test of setBinaryStream() methods
   Body = ...

Table of Contents

 About This Book

 JDBC (Java Database Connectivity) Introduction

 JDK (Java SE) Installation

 Installing and Running Java DB - Derby

 Derby (Java DB) JDBC Driver

 Derby (Java DB) JDBC DataSource Objects

 Java DB (Derby) - DML Statements

 Java DB (Derby) - ResultSet Objects of Queries

 Java DB (Derby) - PreparedStatement

 MySQL Installation on Windows

 MySQL JDBC Driver (MySQL Connector/J)

 MySQL - PreparedStatement

 MySQL - Reference Implementation of JdbcRowSet

 MySQL - JBDC CallableStatement

 MySQL CLOB (Character Large Object) - TEXT

MySQL BLOB (Binary Large Object) - BLOB

 Overview of BLOB (Binary Large Object)

 Create Tables with CLOB Columns

 Inserting BLOB Values with SQL INSERT Statements

 Inserting BLOB Values with setBytes() Method

 Inserting BLOB Values with setBinaryStream() Method

 Closing InputStream Too Early on setBinaryStream()

 Retrieving BLOB Values with getBytes() Method

Retrieving BLOB Values with getBinaryStream() Method

 Retrieving BLOB Values with getBlob() Method

 Inserting BLOB Values with setBlob() Method

 Oracle Express Edition Installation on Windows

 Oracle JDBC Drivers

 Oracle - Reference Implementation of JdbcRowSet

 Oracle - PreparedStatement

 Oracle - JBDC CallableStatement

 Oracle CLOB (Character Large Object) - TEXT

 Oracle BLOB (Binary Large Object) - BLOB

 Microsoft SQL Server Express Edition

 Microsoft JDBC Driver for SQL Server

 Microsoft JDBC Driver - Query Statements and Result Sets

 Microsoft JDBC Driver - DatabaseMetaData Object

 Microsoft JDBC Driver - DDL Statements

 Microsoft JDBC Driver - DML Statements

 SQL Server - PreparedStatement

 SQL Server CLOB (Character Large Object) - TEXT

 SQL Server BLOB (Binary Large Object) - BLOB

 JDBC-ODBC Bridge Driver - sun.jdbc.odbc.JdbcOdbcDriver

 JDBC-ODBC Bridge Driver - Flat Text Files

 JDBC-ODBC Bridge Driver - MS Access

 JDBC-ODBC Bridge Driver - MS SQL Server

 Summary of JDBC Drivers and Database Servers

 Additional Tutorial Notes to Be Added

 Outdated Tutorials

 References

 Full Version in PDF/EPUB