Question

我的任务是将基于Map的存储升级到基于数据库的存储。我的项目配置基于注释。你能解释一下我应该采取哪些措施来实现这个目标吗？以及如何更改我的dao图层代码：

public class TicketDao {

    Set<Ticket> tickets = new HashSet<>();

    public Set<Ticket> getAll() {
        return tickets;
    }

    public void remove(Ticket ticket){
        tickets.remove(ticket);
    }

    public void put(Ticket ticket){
        tickets.add(ticket);
    }
}

Answer 1

创建数据库和架构

配置DataSource和JdbcTemplate。最简单的配置：

@Configuration
public class JdbcConfig {

    @Bean
    public DataSource dataSource(){
        DriverManagerDataSource dataSource = new DriverManagerDataSource();

        dataSource.setDriverClassName("");
        dataSource.setUrl("");
        dataSource.setUsername("");
        dataSource.setPassword("");

        return dataSource;
    }

    @Bean
    public JdbcTemplate jdbcTemplate() {
        return new JdbcTemplate(dataSource());
    }

}

将JdbcTemplate注入dao并使用它

public class TicketDao {

    public static final String DELETE_QUERY = "delete from Ticket where id = ?";
    public static final String INSERT_QUERY = "insert into Ticket values(?, ?)";
    public static final String GET_ALL_QUERY = "select * from Tickets";

    @Autowired
    JdbcTemplate jdbcTemplate;

    public Set<Ticket> getAll() {
        return new HashSet<>(jdbcTemplate.query(GET_ALL_QUERY, new RowMapper<Ticket>() {
            @Override
            public Ticket mapRow(ResultSet rs, int rowNum) throws SQLException {
                Ticket ticket = new Ticket();
                ticket.setId(rs.getString(1));
                //other fields mapping
                return ticket;
            }
        }));
    }

    public void remove(Ticket ticket){
        jdbcTemplate.update(new PreparedStatementCreator() {
            @Override
            public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
                PreparedStatement statement = con.prepareStatement(DELETE_QUERY);
                statement.setString(1, ticket.getId());

                return statement;
            }
        });
    }

    public void put(Ticket ticket){
        Object[] values = {ticket.getId(), ticket.getName()};
        int[] types = {Types.VARCHAR, Types.VARCHAR};

        jdbcTemplate.update(INSERT_QUERY, values, types);
    }
}

基于注释添加Spring JDBC支持

1 个答案: