[3.5 ~ 3.7] JdbcTemplate

[chldbtjd2272]

p.[페이지] 3.6~3.7

질문 : jdbcTemplate에 대한 예제로 update~query까지 template/callback 패턴이 어떤식으로 적용되었는지 정리해주면 좋을듯.
나중에 이 패턴들 보고 같이 얘기해보면 구현 수준도 많이 높아질거 같아

[csbsjy]

요건 블로그 글 작성할 때 정리할게

[csbsjy]

@Override
	@Nullable
	public <T> T query(final String sql, final ResultSetExtractor<T> rse) throws DataAccessException {
		Assert.notNull(sql, "SQL must not be null");
		Assert.notNull(rse, "ResultSetExtractor must not be null");
		if (logger.isDebugEnabled()) {
			logger.debug("Executing SQL query [" + sql + "]");
		}

		/**
		 * Callback to execute the query.
		 */
		class QueryStatementCallback implements StatementCallback<T>, SqlProvider {
			@Override
			@Nullable
			public T doInStatement(Statement stmt) throws SQLException {
				ResultSet rs = null;
				try {
					rs = stmt.executeQuery(sql);
					return rse.extractData(rs);
				}
				finally {
					JdbcUtils.closeResultSet(rs);
				}
			}
			@Override
			public String getSql() {
				return sql;
			}
		}

		return execute(new QueryStatementCallback());
	}

	@Override
	@Nullable
	public <T> T execute(StatementCallback<T> action) throws DataAccessException {
		Assert.notNull(action, "Callback object must not be null");

		Connection con = DataSourceUtils.getConnection(obtainDataSource());
		Statement stmt = null;
		try {
			stmt = con.createStatement();
			applyStatementSettings(stmt);
			T result = action.doInStatement(stmt);
			handleWarnings(stmt);
			return result;
		}
		catch (SQLException ex) {
			// Release Connection early, to avoid potential connection pool deadlock
			// in the case when the exception translator hasn't been initialized yet.
			String sql = getSql(action);
			JdbcUtils.closeStatement(stmt);
			stmt = null;
			DataSourceUtils.releaseConnection(con, getDataSource());
			con = null;
			throw translateException("StatementCallback", sql, ex);
		}
		finally {
			JdbcUtils.closeStatement(stmt);
			DataSourceUtils.releaseConnection(con, getDataSource());
		}
	}

[csbsjy]

제네릭. jdbc.query 의 내부클래스

[csbsjy]

https://javabom.tistory.com/107