旅游网CategoryDaoImpl

public class CategoryDaoImpl implements CategoryDao{
JdbcTemplate jdbcTemplate = new JdbcTemplate(C3P0Util.getDataSource());
@Override
public List queryAll() {
String sql = “select * from tab_category”;
return jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Category.class));
}

//向数据库中插入数据
@Override
public int append(List<Category> categories) {
    return 0;
}

@Override
public Category queryById(int cid) {
    String  sql = "select * from tab_category where cid = ?";
    List<Category> categories = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Category.class), cid);

    if(categories.size() == 1){
        return categories.get(0);
    }else {
        return null;
    }
}

}