Convert Clob to String

Question

How can I get String out of Clob. I did google it, but

myClob.getSubString(0, (int) info.length()));

is the only thing I get. Console says:

java.sql.SQLException: Invalid argument(s) in call at oracle.sql.CLOB.getSubString(CLOB.java:278) at ru.tenet.es09.dao.CompanyDAOImpl.get(CompanyDAOImpl.java:72) at ru.tenet.es09.dao.CompanyDAOImpl.getList(CompanyDAOImpl.java:132) at ru.tenet.es09.dao.AddressDAOImpl.getList(AddressDAOImpl.java:59) at ru.tenet.es09.Test.main(Test.java:11)

It points on getSubString() method. What is wrong?

Possible duplicate of [Most efficient solution for reading CLOB to String, and String to CLOB in Java?](http://stackoverflow.com/questions/2169732/most-efficient-solution-for-reading-clob-to-string-and-string-to-clob-in-java) — CubeJockey, Dec 03 '15 at 14:22

score 4 · Accepted Answer · answered Dec 03 '15 at 14:22

4

Assuming you're using standard JDBC, once you have a ResultSet object you should be able to call ResultSet#getString("clob_field_name") to retrieve your CLOB data.

answered Dec 03 '15 at 14:22

PA001

451
3
12

It will be a cast exception – Tony Dec 03 '15 at 14:31
If you cast it to oracle.sql.CLOB then yes, if you do String clobData = resultSet.getString("clob_field") you'll be fine. – PA001 Dec 03 '15 at 15:31
This worked for me: `if (obj!=null && obj instanceof oracle.sql.CLOB) {obj = rs.getString(i);}`. ` – Don Smith Apr 23 '21 at 21:54

score 3 · Answer 2 · answered Aug 09 '19 at 04:21

3

I know I'm late to this party!. Here is the one liner i used from hibernate library. If hibernate is already integrated to project then we can use annotations to convert clob to java String. In my case i had custom result transformer which read data from multiple tables after costly join. In the resultSetTransformer the below line does the job.

ClobType.INSTANCE.toString((Clob) tuple[2])
// org.hibernate.type.ClobType

answered Aug 09 '19 at 04:21

Raghu Kumar

118
5

god bless u my friend – Alireza Jamali Oct 08 '19 at 15:13

score 0 · Answer 3 · answered Sep 25 '17 at 20:34

this my way (sorry my english)

        res = ps.executeQuery();
        try {
            while (res.next()) {
                System.out.println(res.getClob(1));//confirm data
                sRet = res.getString(1);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            ps.close();
        }

score 0 · Answer 4 · answered Apr 09 '18 at 09:13

Converting String to CLOB

SOobject.setLongStringField( new SerialClob(entityString.toCharArray()));//Converting String to CLOB

Convert Clob to String

public String getLongStringField() {
         Reader reader = null;
            BufferedReader bufferedReader = null;
            try {
                reader = longStringField.getCharacterStream();
                bufferedReader = new BufferedReader(reader);
                return IOUtils.toString(bufferedReader);

            } catch (Exception e) {

                throw new RuntimeException("Error while reading String from CLOB", e);
            } finally {
                IOUtils.closeQuietly(reader);
                IOUtils.closeQuietly(bufferedReader);
            }
    }

Mohit Singh · Answer 5 · 2019-10-01T08:33:16.407

I have created a java method which can create string from a CLOB object:

 public String clobToString(Clob data) {
     StringBuilder sb = new StringBuilder();
        try {
            Reader reader = data.getCharacterStream();
            BufferedReader br = new BufferedReader(reader);

            String line;
            while(null != (line = br.readLine())) {
                sb.append(line);
            }
            br.close();
        } catch (SQLException e) {
            // handle this exception
        } catch (IOException e) {
            // handle this exception
        }
        return sb.toString();

}

Convert Clob to String

5 Answers5