spring-rowmapper
- •RowMapper能夠將數據中的每一行封裝成用戶定義的類,在數據庫查詢中,若是返回的類型是用戶自定義的類型則須要包裝,若是是Java自定義的類型,如:String則不須要,Spring最新的類SimpleJdbcTemplate使用更加簡單了。
- •下面這個實例說明了如何使用RowMapp,從網上下載的代碼,還行能說明問題。在使用過程當中咱們能夠將內部類作成POJO的外部類,只要實現RowMapper接口便可。若是用戶想讓ApplicationContext進行定義仍是要謹慎。畢竟實現RowMapper接口須要給一個類增長一個mapRow方法,讓類承受的功能較多,不利於分析系統
- •實現1、在內部創建內聯類實現RowMapper接口
- •
- •package hysteria.contact.dao.impl;
- •
- •import java.sql.ResultSet;
- •import java.sql.SQLException;
- •import java.sql.Types;
- •import java.util.List;
- •
- •import org.springframework.jdbc.core.JdbcTemplate;
- •import org.springframework.jdbc.core.RowMapper;
- •
- •import hysteria.contact.dao.ItemDAO;
- •import hysteria.contact.domain.Item;
- •
- •public class ItemDAOImpl implements ItemDAO {
- • private JdbcTemplate jdbcTemplate;
- •
- • public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
- • this.jdbcTemplate = jdbcTemplate;
- • }
- •
- • public Item insert(Item item) {
- • String sql = "INSERT INTO items(user_id,name,phone,email) VALUES(?,?,?,?)";
- • Object[] params = new Object[] { item.getUserId(), item.getName(),
- • item.getPhone(), item.getEmail() };
- • int[] types = new int[] { Types.INTEGER, Types.VARCHAR, Types.CHAR,
- • Types.VARCHAR };
- • jdbcTemplate.update(sql, params, types);
- • return item;
- • }
- •
- • public Item update(Item item) {
- • String sql = "UPDATE items SET name = ?, phone = ?, email = ? WHERE id = ?";
- • Object[] params = new Object[] { item.getName(), item.getPhone(),
- • item.getEmail(), item.getId() };
- • int[] types = new int[] { Types.VARCHAR, Types.CHAR, Types.VARCHAR,
- • Types.VARCHAR, Types.INTEGER };
- • jdbcTemplate.update(sql, params, types);
- •
- • return item;
- • }
- •
- • public void delete(Item item) {
- • String sql = "DELETE FROM items WHERE id = ?";
- • Object[] params = new Object[] { item.getId() };
- • int[] types = new int[] { Types.INTEGER };
- • jdbcTemplate.update(sql, params, types);
- • }
- •
- • public Item findById(int id) {
- • String sql = "SELECT * FROM items WHERE id = ?";
- • Object[] params = new Object[] { id };
- • int[] types = new int[] { Types.INTEGER };
- • List items = jdbcTemplate.query(sql, params, types, new ItemMapper());
- • if (items.isEmpty()) {
- • return null;
- • }
- • return (Item) items.get(0);
- • }
- •
- • public List<Item> findAll() {
- • String sql = "SELECT * FROM items";
- • return jdbcTemplate.query(sql, new ItemMapper());
- • }
- •
- • public List<Item> findAllByUser(int user_id) {
- • String sql = "SELECT * FROM items WHERE user_id = ?";
- • Object[] params = new Object[] { user_id };
- • int[] types = new int[] { Types.INTEGER };
- • List items = jdbcTemplate.query(sql, params, types, new ItemMapper());
- • return items;
- • }
- •
- • protected class ItemMapper implements RowMapper {
- •
- • public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
- • Item item = new Item();
- • item.setId(rs.getInt("id"));
- • item.setUserId(rs.getInt("user_id"));
- • item.setName(rs.getString("name"));
- • item.setPhone(rs.getString("phone"));
- • item.setEmail(rs.getString("email"));
- •
- • return item;
- • }
- •
- • }
- •
- •}
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