Spring中JdbcTemplate中使用RowMapper

package com.cxl.demo.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import com.cxl.demo.entity.User;
public class UserDaoImpl {
	private JdbcTemplate jdbcTemplate;

	public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
		this.jdbcTemplate = jdbcTemplate;
	}

	public List<User> getUserByName(String username) {
		String sql = "select * from t_user where username = ?";
		Object[] params = new Object[] { username };
		List<User> users = null;
		/**
		 * 使用接口实现类
		 */
		users = jdbcTemplate.query(sql, params, new UserRowMapper());
		/**
		 * 使用匿名内部类
		 * 如果UserRowMapper类只使用一次，单独为其创建一个类多余，可以使用匿名类
		 * 省略了书写一个实现类
		 */
		users = jdbcTemplate.query(sql, params,
				new RowMapper<User>() {
					@Override
					public User mapRow(ResultSet rs, int rowNum) throws SQLException {
						User user = new User();
						user.setId(rs.getInt("id"));
						user.setUsername(rs.getString("username"));
						user.setPassword(rs.getString("password"));
						return user;
					}
				});
		return (users != null && users.size() > 0) ? users : null;
	}
	
	public class UserRowMapper implements RowMapper<User> {

		@Override
		public User mapRow(ResultSet rs, int rowNum) throws SQLException {
			User user = new User();
			user.setId(rs.getInt("id"));
			user.setUsername(rs.getString("username"));
			user.setPassword(rs.getString("password"));
			return user;
		}
		
	}
}