JDBC Tutorials - Herong's Tutorial Examples - 3.10, by Dr. Herong Yang
Inserting BLOB Values with setBlob() Method
This section describes how to insert BLOB values with the PreparedStatement.setBlob() method.
If you want to insert a BLOB column with a character string that comes from a java.sql.Blob object, you can directly set the value with PreparedStatement.setBlob() method.
To test this, I wrote the following program to copy some records with BLOB values as new records back into the same table. During the copy process, the BLOB values are also modified with some Blob object methods - The first 6 bytes are replaced with 0 values.
/* MySqlBlobSetBlob.java
* Copyright (c) HerongYang.com. All Rights Reserved.
*/
import java.io.*;
import java.sql.*;
public class MySqlBlobSetBlob {
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();
// Deleting records for re-testing
Statement sta = con.createStatement();
sta.executeUpdate(
"DELETE FROM Image WHERE Subject LIKE 'Copy of %'");
// Creating a PreparedStatement for inserting new records
PreparedStatement ps = con.prepareStatement(
"INSERT INTO Image (Subject, Body) VALUES (?,?)");
// Looping though the first 3 records
ResultSet res = sta.executeQuery(
"SELECT * FROM Image ORDER BY ID");
int i = 0;
while (res.next() && i<3) {
i++;
System.out.println("Copying record ID: "+res.getInt("ID"));
String subject = res.getString("Subject");
Blob body = res.getBlob("Body");
// Modifying the Blob object
byte[] chuck = {(byte)0x00, (byte)0x00, (byte)0x00,
(byte)0x00, (byte)0x00, (byte)0x00};
body.setBytes(1,chuck);
// Inserting a new record with setBlob()
ps.setString(1, "Copy of "+subject);
ps.setBlob(2,body);
ps.executeUpdate();
}
ps.close();
res.close();
// Checking the new records
res = sta.executeQuery(
"SELECT * FROM Image WHERE Subject LIKE 'Copy of %'");
while (res.next()) {
System.out.println("Record ID: "+res.getInt("ID"));
System.out.println(" Subject = "+res.getString("Subject"));
byte[] body = res.getBytes("Body");
String bodyHex = bytesToHex(body, 32);
System.out.println(" Body in HEX = "+bodyHex+"...");
}
res.close();
sta.close();
con.close();
} catch (Exception e) {
System.err.println("Exception: "+e.getMessage());
e.printStackTrace();
}
}
public static String bytesToHex(byte[] bytes, int max) {
StringBuffer buffer = new StringBuffer();
for (int i=0; i<bytes.length && i<max; i++) {
buffer.append(Integer.toHexString(bytes[i] & 0xFF));
}
return buffer.toString().toUpperCase();
}
}
The program performed exactly as I expected:
herong> java -cp .:mysql-connector-java-8.0.19.jar MySqlBlobSetBlob.java Copying record ID: 1 Copying record ID: 2 Copying record ID: 4 Record ID: 5 Subject = Copy of Test on INSERT statement Body in HEX = 000000C8CABCCCCEB9C9CBBB... Record ID: 6 Subject = Copy of Test of the setBytes() method Body in HEX = 000000C8CABCCCCEB9C9CBBB... Record ID: 7 Subject = Copy of Test of setBinaryStream() methods Body in HEX = 0000000340B5A03B0487049A02048804AA0204BA...
Table of Contents
JDBC (Java Database Connectivity) Introduction
Installing and Running Java DB - Derby
Derby (Java DB) JDBC DataSource Objects
Java DB (Derby) - DML Statements
Java DB (Derby) - ResultSet Objects of Queries
Java DB (Derby) - PreparedStatement
MySQL JDBC Driver (MySQL Connector/J)
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 - Reference Implementation of JdbcRowSet
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