java clob-string转换工具

import java.io.Reader;
import java.sql.Clob;

public class ClobTransfer {
	 /**
	 * 将String转成Clob ,静态方法
	 * 
	 * @param str
	 *            字段
	 * @return clob对象，如果出现错误，返回 null
	 */
	public static Clob stringToClob(String str) {
		if (null == str)
			return null;
		else {
			try {
				java.sql.Clob c = new javax.sql.rowset.serial.SerialClob(str
						.toCharArray());
				return c;
			} catch (Exception e) {
				return null;
			}
		}
	}

	/**
	 * 将Clob转成String ,静态方法
	 * 
	 * @param clob
	 *            字段
	 * @return 内容字串，如果出现错误，返回 null
	 */
	public static String clobToString(Clob clob) {
		if (clob == null)
			return null;
		StringBuffer sb = new StringBuffer();
		Reader clobStream = null;
		try {
			clobStream = clob.getCharacterStream();
			char[] b = new char[60000];// 每次获取60K
			int i = 0;
			while ((i = clobStream.read(b)) != -1) {
				sb.append(b, 0, i);
			}
		} catch (Exception ex) {
			sb = null;
		} finally {
			try {
				if (clobStream != null) {
					clobStream.close();
				}
			} catch (Exception e) {
			}
		}
		if (sb == null)
			return null;
		else
			return sb.toString();
	}
	
	public static String clobToString(oracle.sql.CLOB clob){
		try{
			Reader inStream = clob.getCharacterStream();
	        char[] c = new char[(int) clob.length()];
	        inStream.read(c);
	        String data = new String(c);
	        inStream.close();
			return data;
		}catch(Exception e){
			e.printStackTrace();
			return "";
		}
	}
}