轻量级java web实践-8（框架源码-6）
持久化，数据库操作部分，借鉴osc部分代码，使用dbutils组件
public abstract class DataAccess
{
private static final Logger log = LoggerFactory.getLogger(DataAccess.class);
private Connection conn;
/**
* @param conn 数据库连接
*/
protected DataAccess(Connection conn)
{
this.conn = conn;
}
/**
* 插入数据
*
* @param sql
* @param generatedKeysConverter 主键映射
* @param params
* @return 主键
* @throws DataAccessException
*/
protected <T> T insert(String sql, ResultConverter<T> generatedKeysConverter, Object... params) throws DataAccessException
{
try
{
PreparedStatement pstmt = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
setParameters(pstmt, params);
executeUpdate(pstmt);
ResultSet rs = pstmt.getGeneratedKeys();
nextResult(rs);
return convertResult(rs, generatedKeysConverter);
}
catch (SQLException e)
{
e.printStackTrace();
log.error(e.getMessage(), e);
throw new DataAccessException(e);
}
}
/**
* 更新数据
*
* @param sql
* @param params
* @return 影响行数
* @throws DataAccessException
*/
protected int update(String sql, Object... params) throws DataAccessException
{
return executeUpdate(getPreparedStatement(sql, params));
}
/**
* 查询单个结果
*
* @param <T>
* @param sql
* @param converter
* @param params
* @return
*/
protected <T> T queryForObject(String sql, ResultConverter<T> converter, Object... params)
{
ResultSet rs = executeQuery(sql, params);
if (nextResult(rs))
{
return convertResult(rs, converter);
}
else
{
return null;
}
}
/**
* 查询结果列表
*
* @param <T>
* @param sql
* @param converter
* @param params
* @return
*/
protected <T> List<T> queryForList(String sql, ResultConverter<T> converter, Object... params)
{
ResultSet rs = executeQuery(sql, params);
List<T> list = new ArrayList<T>();
while (nextResult(rs))
{
list.add(convertResult(rs, converter));
}
return list;
}
/**
* @param sql SQL语句
* @return 预编译声明
*/
private PreparedStatement getPreparedStatement(String sql, Object... params) throws DataAccessException
{
PreparedStatement pstmt = getPreparedStatement(sql);
setParameters(pstmt, params);
return pstmt;
}
/**
* @param sql SQL语句
* @return 预编译声明
*/
private PreparedStatement getPreparedStatement(String sql) throws DataAccessException
{
try
{
return conn.prepareStatement(sql);
}
catch (SQLException e)
{
e.printStackTrace();
log.error(e.getMessage(), e);
throw new DataAccessException(e);
}
}
/**
* 为预编译声明传入参数
*
* @param pstmt 预编译声明
* @param params 参数
* @throws DataAccessException
*/
private void setParameters(PreparedStatement pstmt, Object... params) throws DataAccessException
{
try
{
for (int i = 0; i < params.length; i++)
{
pstmt.setObject(i + 1, params[i]);
}
}
catch (SQLException e)
{
e.printStackTrace();
log.error(e.getMessage(), e);
throw new DataAccessException(e);
}
}
/**
* 执行更新操作
*
* @param pstmt
* @return 影响行数
* @throws DataAccessException
*/
private int executeUpdate(PreparedStatement pstmt) throws DataAccessException
{
try
{
return pstmt.executeUpdate();
}
catch (SQLException e)
{
e.printStackTrace();
log.error(e.getMessage(), e);
throw new DataAccessException(e);
}
}
/**
* 执行查询操作
*
* @param pstmt 预编译声明
* @return 结果集
* @throws DataAccessException
*/
private ResultSet executeQuery(PreparedStatement pstmt) throws DataAccessException
{
try
{
return pstmt.executeQuery();
}
catch (SQLException e)
{
e.printStackTrace();
log.error(e.getMessage(), e);
throw new DataAccessException(e);
}
}
/**
* 执行查询操作
*
* @param sql SQL语句
* @param params 参数
* @return 结果集
* @throws DataAccessException
*/
private ResultSet executeQuery(String sql, Object... params) throws DataAccessException
{
return executeQuery(getPreparedStatement(sql, params));
}
/**
* 移动到下一行记录
*
* @param rs 结果集
* @return 是否有下一行记录
* @throws DataAccessException
*/
private boolean nextResult(ResultSet rs) throws DataAccessException
{
try
{
return rs.next();
}
catch (SQLException e)
{
e.printStackTrace();
log.error(e.getMessage(), e);
throw new DataAccessException(e);
}
}
/**
* 映射
*
* @param rs 结果集
* @return 映射结果
* @throws DataAccessException
*/
private <T> T convertResult(ResultSet rs, ResultConverter<T> converter) throws DataAccessException
{
try
{
return converter.convert(rs);
}
catch (SQLException e)
{
e.printStackTrace();
log.error(e.getMessage(), e);
throw new DataAccessException(e);
}
}
}
其余DBManager，DBUtils，参考请OSC源码