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

 About This Book

 JDBC (Java Database Connectivity) Introduction

 JDK (Java SE) Installation

 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

 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

 Using Connection Pool with JDBC

 Archived Tutorials

 References

 Full Version in PDF/EPUB