oracle CLOB字段轉換位VARCHAR
1.實際上處理CLOB字段的時候，直接TO_CHAR，當長度超過4000的時候，會報錯，提示列被截取；
CLOB轉varchar2：select to_char(CLOB字段) from table
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2.直接使用SUBSTR對CLOB字段進行截取，是不能起到任何作用的；
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3.可以使用dbms_lob.substr(clobcolumn,4000)，對CLOB字段進行截取；截取的長度是4000還是2000根據存儲的是漢字和數據決定長度；
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java獲取oracle中CLOB字段，轉換成String
try {
PreparedStatement stmt = session.connection().prepareStatement(sql);
ResultSet rs = stmt.executeQuery();
while (rs.next())
{
Clob clob = (Clob)rs.getObject(1);
result = ClobToString(clob);
}} catch (HibernateException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
session.close();
}//oracle.sql.Clob類型轉換成String類型public String ClobToString(Clob clob) throws SQLException, IOException {String reString = "";
Reader is = clob.getCharacterStream();// 得到流
BufferedReader br = new BufferedReader(is);
String s = br.readLine();
StringBuffer sb = new StringBuffer();
while (s != null) {// 執行循環將字符串全部取出付值給StringBuffer由StringBuffer轉成STRING
sb.append(s);
s = br.readLine();
}
reString = sb.toString();
return reString;
}
