JDBC Tutorials - Herong's Tutorial Examples - v3.12, by Dr. Herong Yang
Retrieving CLOB Values with getString() Method
This section describes how to retrieve CLOB values with the ResultSet.getString() method.
The simplest way to retrieve the character string value from a CLOB column is to use the getString() method on the ResultSet object. Here is short example program:
/* MySqlClobGetString.java * Copyright (c) HerongYang.com. All Rights Reserved. */ import java.io.*; import java.sql.*; public class MySqlClobGetString { 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 getString() Statement sta = con.createStatement(); ResultSet res = sta.executeQuery("SELECT * FROM Article"); int i = 0; while (res.next() && i<3) { i++; System.out.println("Record ID: "+res.getInt("ID")); System.out.println(" Subject = "+res.getString("Subject")); String body = res.getString("Body"); if (body.length() > 100) body = body.substring(0,100); System.out.println(" Body = "+body+"..."); } res.close(); sta.close(); con.close(); } catch (Exception e) { System.err.println("Exception: "+e.getMessage()); e.printStackTrace(); } } }
The output of the program confirms that CLOB values can be retrieved with getString() method on the ResultSet object:
herong> java -cp .:mysql-connector-java.jar MySqlClobGetString.java Record ID: 1 Subject = Test on INSERT statement Body = A BLOB (Binary Large OBject) is a large chunk of data which is stored in a database.... Record ID: 2 Subject = Test of the setString() method Body = He is wonderful and strange and who knows how old he is, he thought. Never have I had such a strong ... Record ID: 5 Subject = Test of setCharacterStream() methods Body = /* MySqlClobSetCharacterStream.java * Copyright (c) HerongYang.com. All Rights Reserved. */ ...
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
Overview of CLOB (Character Large Object)
Create Tables with CLOB Columns
Inserting CLOB Values with SQL INSERT Statements
Inserting CLOB Values with setString() Method
Inserting CLOB Values with setCharacterStream() Method
►Retrieving CLOB Values with getString() Method
Retrieving CLOB Values with getCharacterStream() Method
Retrieving CLOB Values with getClob() Method
Inserting CLOB Values with setClob() Method
MySQL BLOB (Binary Large Object) - BLOB
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