Write an JDBC example to retrieve Clob value from a table using the getCharacterStream() method?

The ResultSet interface provides the method named getClob() to retrieve clob datatype from a table in a database. In addition to this it also provides a method named getCharacterStream()

Like getClob() this method also accepts an integer representing the index of the column (or, a String value representing the name of the column) and retrieves the value at the specified column. The difference is unlike the getClob() method (which returns a Clob object) this method returns an object of the Reader class.

Example

Assume we have created a table named MyData in the database with the following description.

+---------+--------------+------+-----+---------+-------+ | Field   | Type         | Null | Key | Default | Extra | +---------+--------------+------+-----+---------+-------+ | Name    | varchar(255) | YES  |     | NULL | | | Article | longtext     | YES  |     | NULL | | +---------+--------------+------+-----+---------+-------+

And, we have inserted large textual data in it with name JavaFX. Following program retrieves the contents of the table MyData using the getString() and getCharacterStream() methods.

import java.io.FileWriter; import java.io.Reader; import java.sql.Clob; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; public class RetrievingClob_CharStream {    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 Statement object       Statement stmt = con.createStatement();       //retrieving the data       ResultSet rs = stmt.executeQuery("select * from MyData");       int j = 0;       System.out.println("Contents of the table are: ");       while(rs.next()) {          System.out.println(rs.getString("Name"));          Clob clob = rs.getClob("Article");          Reader r = clob.getCharacterStream();          String filePath = "E:\Data\clob_output"+j+".txt";          FileWriter writer = new FileWriter(filePath);          int i;          while ((i=r.read())!=-1) {             writer.write(i);          }          writer.close();          System.out.println(filePath);          j++;       }    }   }

Output

Connection established...... Contents of the table...... JavaFX E:\Data\clob_output0.txt

If you observe the file in the obtained path you can see the contents of the Clob retrieved from the table as shown below: