Java怎样能把Oracle的Blob类型的内容导出到本地？

Question

Java怎样能把Oracle的Blob类型的内容导出到本地？假如里面存到是文件.

Answer 1

Oracle中的BLOB和CLOB

Answer 2

oracle 官方文档 CLOB 10g
http://www.oracle.com/technology/sample_code/tech/java/codesnippet/jdbc/clob10g/handlingclobsinoraclejdbc10g.html
oracle 官方文件 LOB sample
http://www.oracle.com/technology/sample_code/tech/java/sqlj_jdbc/files/advanced/LOBSample/LOBSample.java.html

Answer 3

BLOB转byte[]
private static byte[] getBlobData(Blob blob) throws SQLException {
        byte[] content = new byte[(int) blob.length()];
        InputStream in = null;
        try {
            in = blob.getBinaryStream();
            int bytes = in.read(content, 0, (int) blob.length());
            if (bytes != blob.length()) {
                throw new SQLException("JDBCUtil.getBlobData failed, read " + bytes + " bytes, expected "
                        + blob.length());
            }
        }
        catch (IOException e) {
            throw new SQLException("JDBCUtil.getBlobData failed: " + e.getMessage());
        }
        finally {
            if (in != null) {
                try {
                    in.close();
                }
                catch (IOException e) {
                    // ignore
                    e.printStackTrace();
                }
            }
        }
        return content;
    }

Answer 4

/**   
     * 读出数据并存成文件   
     *    
     * @param id   
     * @param file   
     */   
    public static void readClobDataUseSQL(Integer id, File file) {    
        Connection conn = getConnection();    
        try {    
            Statement st = conn.createStatement();    
            String sql = "select CONTENT from TEST_CLOB where ID = " + id;    
            ResultSet rs = st.executeQuery(sql);    
   
            if (rs.next()) {    
   
                CLOB clob = (CLOB) rs.getClob("CONTENT");    
   
                String result = convertClobToString(clob);    
                System.out.println(result);    
                FileUtils.writeStringToFile(file,result, "utf-8");    
            }    
        } catch (Exception e) {    
            e.printStackTrace();    
        } finally {    
            try {    
                conn.close();    
            } catch (SQLException e) {    
                e.printStackTrace();    
            }    
        }    
   
    }