001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.jdbc.core; 018 019import java.sql.ResultSet; 020import java.sql.SQLException; 021 022/** 023 * An interface used by {@link JdbcTemplate} for mapping rows of a 024 * {@link java.sql.ResultSet} on a per-row basis. Implementations of this 025 * interface perform the actual work of mapping each row to a result object, 026 * but don't need to worry about exception handling. 027 * {@link java.sql.SQLException SQLExceptions} will be caught and handled 028 * by the calling JdbcTemplate. 029 * 030 * <p>Typically used either for {@link JdbcTemplate}'s query methods 031 * or for out parameters of stored procedures. RowMapper objects are 032 * typically stateless and thus reusable; they are an ideal choice for 033 * implementing row-mapping logic in a single place. 034 * 035 * <p>Alternatively, consider subclassing 036 * {@link org.springframework.jdbc.object.MappingSqlQuery} from the 037 * {@code jdbc.object} package: Instead of working with separate 038 * JdbcTemplate and RowMapper objects, you can build executable query 039 * objects (containing row-mapping logic) in that style. 040 * 041 * @author Thomas Risberg 042 * @author Juergen Hoeller 043 * @see JdbcTemplate 044 * @see RowCallbackHandler 045 * @see ResultSetExtractor 046 * @see org.springframework.jdbc.object.MappingSqlQuery 047 */ 048public interface RowMapper<T> { 049 050 /** 051 * Implementations must implement this method to map each row of data 052 * in the ResultSet. This method should not call {@code next()} on 053 * the ResultSet; it is only supposed to map values of the current row. 054 * @param rs the ResultSet to map (pre-initialized for the current row) 055 * @param rowNum the number of the current row 056 * @return the result object for the current row (may be {@code null}) 057 * @throws SQLException if a SQLException is encountered getting 058 * column values (that is, there's no need to catch SQLException) 059 */ 060 T mapRow(ResultSet rs, int rowNum) throws SQLException; 061 062}