자바를 이용한 BLOB CLOB조작법

1) import 시켜야할 API

① oracle.sql.BLOB

② oracle.sql.CLOB

③ oracle.jdbc.driver.OracleResultSet

2) CLOB

① DB에 CLOB 데이터형 쓰기

// UPDATE 또는 INSERT 명령으로 DB 에 공간 확보
String query = "UPDATE TABLE SET CLOB_DATA = EMPTY_CLOB() " ;
stmt.executeUpdate(query);

// 그런 다음 다시 요놈을 다시 SELECT
query = "SELECT CLOB_DATA FROM TABLE WHERE ~ " ;

stmt = dbConn.createStatement();
rs = stmt.executeQuery(query);

if(rs.next()) {
CLOB clob = null;
Writer writer = null;
Reader src = null;
char[] buffer = null;
int read = 0;

clob = ((OracleResultSet)rs).getCLOB(1);
writer = clob.getCharacterOutputStream();

// str -> DB에 넣을 내용
src = new CharArrayReader(str.toCharArray());
buffer = new char[1024];
read = 0;
while ( (read = src.read(buffer,0,1024)) != -1) {
writer.write(buffer, 0, read); // write clob.
}
src.close();
writer.close();
}

dbConn.commit();
dbConn.setAutoCommit(true);

② DB에서 CLOB 데이터형 읽기

// SELECT
String query = "SELECT CLOB_DATA FROM TABLE WHERE ~ " ;

stmt = dbConn.createStatement();
rs = stmt.executeQuery(query);

if(rs.next()) {

StringBuffer output = new StringBuffer();
Reader input = rs.getCharacterStream("CLOB_DATA");
char[] buffer = new char[1024];
int byteRead = 0;
while((byteRead=input.read(buffer,0,1024))!=-1){
output.append(buffer,0,byteRead);
}

// contents -> CLOB 데이터가 저장될 String
String contents = output.toString();

}

dbConn.commit();
dbConn.setAutoCommit(true);

3) BLOB

① DB에 BLOB 데이터형 쓰기

// UPDATE 또는 INSERT 명령으로 DB 에 공간 확보
String query = "UPDATE TABLE SET BLOB_DATA = EMPTY_BLOB() " ;
stmt.executeUpdate(query);

// 그런 다음 다시 요놈을 다시 SELECT
query = "SELECT BLOB_DATA FROM TABLE WHERE ~ " ;

stmt = dbConn.createStatement();
rs = stmt.executeQuery(query);

if(rs.next()) {

BLOB blob = null;
BufferedOutputStream out = null;
BufferedInputStream in = null;
byte[] buf = null;
int bytesRead= 0;

blob = ((OracleResultSet)rs).getBLOB(1);
out = new BufferedOutputStream(blob.getBinaryOutputStream());

// str -> DB에 넣을 내용
in = new BufferedInputStream(new StringBufferInputStream(str));
int nFileSize = (int)str.length();
buf = new byte[nFileSize];

while ((bytesRead = in.read(buf)) != -1){
out.write(buf, 0, bytesRead);

}

in.close();
out.close();
}

dbConn.commit();
dbConn.setAutoCommit(true);

② DB에서 BLOB 데이터형 읽기

// SELECT
String query = "SELECT CLOB_DATA FROM TABLE WHERE ~ " ;

stmt = dbConn.createStatement();
rs = stmt.executeQuery(query);

if(rs.next()) {

BLOB blob = ((OracleResultSet)rs).getBLOB(1);

BufferedInputStream in = new BufferedInputStream(blob.getBinaryStream());
int nFileSize = (int)blob.length();
byte[] buf = new byte [nFileSize];
int nReadSize = in.read(buf, 0, nFileSize);
in.close();

// contents -> BLOB 데이터가 저장될 String

String contents = new String(buf);
}

dbConn.commit();
dbConn.setAutoCommit(true);