Read Clob Data As Ascii String : LobHandler « Spring « Java Tutorial

1. Java Tutorial
2. Spring
3. LobHandler

File: context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:util="http://www.springframework.org/schema/util"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:lang="http://www.springframework.org/schema/lang"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
                           http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.0.xsd
                           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
                           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
                           http://www.springframework.org/schema/lang http://www.springframework.org/schema/lang/spring-lang-2.0.xsd">

<!--
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/>
        <property name="url" value="jdbc:oracle:thin:@oracle.devcake.co.uk:1521:INTL"/>
        <property name="username" value="sa"/>
        <property name="password" value=""/>
    </bean>
-->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="org.hsqldb.jdbcDriver"/>
    <property name="url" value="jdbc:hsqldb:mem:."/>
    <property name="username" value="sa"/>
    <property name="password" value=""/>
    </bean>
<!--
    <bean id="mysqlDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://dbhost-prospring-psql/prospring"/>
        <property name="username" value="sa"/>
        <property name="password" value=""/>
    </bean>
-->
    <bean id="lobHandler" class="org.springframework.jdbc.support.lob.OracleLobHandler">
        <property name="nativeJdbcExtractor" ref="nativeJdbcExtractor"/>
    </bean>

    <bean id="nativeJdbcExtractor" class="org.springframework.jdbc.support.nativejdbc.CommonsDbcpNativeJdbcExtractor"/>

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>


</beans>

File: Main.java

import java.io.IOException;
import java.io.InputStream;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.sql.DataSource;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.support.lob.LobHandler;

class Main {
  public static void main(String args[]) throws Exception {
    ApplicationContext ac = new ClassPathXmlApplicationContext("context.xml", Main.class);
    DataSource dataSource = (DataSource) ac.getBean("dataSource");
    // DataSource mysqlDataSource = (DataSource) ac.getBean("mysqlDataSource");

    final LobHandler lobHandler = (LobHandler) ac.getBean("lobHandler");

    JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
    jdbcTemplate.query("select comments from t_customer where id=?", new Object[] { 2L },
        new RowMapper() {
          private String readAsAscii(InputStream is) throws IOException {
            StringBuffer out = new StringBuffer();
            byte[] buffer = new byte[1024];
            int read;
            try {
              while ((read = is.read(buffer, 0, buffer.length)) > 0) {
                for (int i = 0; i < read; i++) {
                  out.append(String.format("%x", buffer[i]));
                }
              }
            } finally {
              is.close();
            }
            return out.toString();
          }

          public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
            InputStream stream = lobHandler.getClobAsAsciiStream(rs, 1);
            try {
              return readAsAscii(stream);
            } catch (IOException ex) {
              // 
            }
            return null;
          }
        });

  }
}

28.43.LobHandler
	28.43.1.	Use Lob Handler To Handle Large Chunk of Data
	28.43.2.	Deal With Binary Stream With Lob Handler
	28.43.3.	Read Clob Data As Ascii String
	28.43.4.	Insert Clob Data