StatementHandler
语句处理器,主要负责语句的创建、参数的设置、语句的执行。不负责结果集的处理。
Statement prepare(Connection connection, Integer transactionTimeout) throws SQLException void parameterize(Statement statement) throws SQLException void batch(Statement statement) throws SQLException int update(Statement statement) throws SQLException List<E> query(Statement statement, ResultHandler resultHandler) throws SQLException Cursor<E> queryCursor(Statement statement) throws SQLException
BaseStatementHandler
实现公共部分,具体差异通过抽象方法,留给子类实现。
@Override public Statement prepare(Connection connection, Integer transactionTimeout) throws SQLException { ErrorContext.instance().sql(boundSql.getSql()); Statement statement = null; try { statement = instantiateStatement(connection); setStatementTimeout(statement, transactionTimeout); setFetchSize(statement); return statement; } catch (SQLException e) { closeStatement(statement); throw e; } catch (Exception e) { closeStatement(statement); throw new ExecutorException("Error preparing statement. Cause: " + e, e); } } protected abstract Statement instantiateStatement(Connection connection) throws SQLException;
首先语句级别的配置,其次配置文件中的配置。
protected void setStatementTimeout(Statement stmt, Integer transactionTimeout) throws SQLException { Integer queryTimeout = null; if (mappedStatement.getTimeout() != null) { queryTimeout = mappedStatement.getTimeout(); } else if (configuration.getDefaultStatementTimeout() != null) { queryTimeout = configuration.getDefaultStatementTimeout(); } if (queryTimeout != null) { stmt.setQueryTimeout(queryTimeout); } StatementUtil.applyTransactionTimeout(stmt, queryTimeout, transactionTimeout); }
首先语句级别的配置,其次配置文件中的配置。
protected void setFetchSize(Statement stmt) throws SQLException { Integer fetchSize = mappedStatement.getFetchSize(); if (fetchSize != null) { stmt.setFetchSize(fetchSize); return; } Integer defaultFetchSize = configuration.getDefaultFetchSize(); if (defaultFetchSize != null) { stmt.setFetchSize(defaultFetchSize); } }
StatementUtil
如果两个参数都有值,设置较小的那一个。
public static void applyTransactionTimeout(Statement statement, Integer queryTimeout, Integer transactionTimeout) throws SQLException { if (transactionTimeout == null){ return; } Integer timeToLiveOfQuery = null; if (queryTimeout == null || queryTimeout == 0) { timeToLiveOfQuery = transactionTimeout; } else if (transactionTimeout < queryTimeout) { timeToLiveOfQuery = transactionTimeout; } if (timeToLiveOfQuery != null) { statement.setQueryTimeout(timeToLiveOfQuery); } }
SimpleStatementHandler
无参数sql语句的执行。
@Override protected Statement instantiateStatement(Connection connection) throws SQLException { if (mappedStatement.getResultSetType() != null) { return connection.createStatement(mappedStatement.getResultSetType().getValue(), ResultSet.CONCUR_READ_ONLY); } else { return connection.createStatement(); } } @Override public void parameterize(Statement statement) throws SQLException { // N/A } @Override public int update(Statement statement) throws SQLException { String sql = boundSql.getSql(); Object parameterObject = boundSql.getParameterObject(); KeyGenerator keyGenerator = mappedStatement.getKeyGenerator(); int rows; if (keyGenerator instanceof Jdbc3KeyGenerator) { statement.execute(sql, Statement.RETURN_GENERATED_KEYS); rows = statement.getUpdateCount(); keyGenerator.processAfter(executor, mappedStatement, statement, parameterObject); } else if (keyGenerator instanceof SelectKeyGenerator) { statement.execute(sql); rows = statement.getUpdateCount(); keyGenerator.processAfter(executor, mappedStatement, statement, parameterObject); } else { statement.execute(sql); rows = statement.getUpdateCount(); } return rows; } @Override public void batch(Statement statement) throws SQLException { String sql = boundSql.getSql(); statement.addBatch(sql); } @Override public <E> List<E> query(Statement statement, ResultHandler resultHandler) throws SQLException { String sql = boundSql.getSql(); statement.execute(sql); return resultSetHandler.<E>handleResultSets(statement); } @Override public <E> Cursor<E> queryCursor(Statement statement) throws SQLException { String sql = boundSql.getSql(); statement.execute(sql); return resultSetHandler.<E>handleCursorResultSets(statement); }
PreparedStatementHandler
参数化sql语句的执行。
@Override protected Statement instantiateStatement(Connection connection) throws SQLException { String sql = boundSql.getSql(); if (mappedStatement.getKeyGenerator() instanceof Jdbc3KeyGenerator) { String[] keyColumnNames = mappedStatement.getKeyColumns(); if (keyColumnNames == null) { return connection.prepareStatement(sql, PreparedStatement.RETURN_GENERATED_KEYS); } else { return connection.prepareStatement(sql, keyColumnNames); } } else if (mappedStatement.getResultSetType() != null) { return connection.prepareStatement(sql, mappedStatement.getResultSetType().getValue(), ResultSet.CONCUR_READ_ONLY); } else { return connection.prepareStatement(sql); } } @Override public void parameterize(Statement statement) throws SQLException { parameterHandler.setParameters((PreparedStatement) statement); } @Override public int update(Statement statement) throws SQLException { PreparedStatement ps = (PreparedStatement) statement; ps.execute(); int rows = ps.getUpdateCount(); Object parameterObject = boundSql.getParameterObject(); KeyGenerator keyGenerator = mappedStatement.getKeyGenerator(); keyGenerator.processAfter(executor, mappedStatement, ps, parameterObject); return rows; } @Override public void batch(Statement statement) throws SQLException { PreparedStatement ps = (PreparedStatement) statement; ps.addBatch(); } @Override public <E> List<E> query(Statement statement, ResultHandler resultHandler) throws SQLException { PreparedStatement ps = (PreparedStatement) statement; ps.execute(); return resultSetHandler.<E> handleResultSets(ps); } @Override public <E> Cursor<E> queryCursor(Statement statement) throws SQLException { PreparedStatement ps = (PreparedStatement) statement; ps.execute(); return resultSetHandler.<E> handleCursorResultSets(ps); }
CallableStatementHandler
存储过程的执行。
@Override protected Statement instantiateStatement(Connection connection) throws SQLException { String sql = boundSql.getSql(); if (mappedStatement.getResultSetType() != null) { return connection.prepareCall(sql, mappedStatement.getResultSetType().getValue(), ResultSet.CONCUR_READ_ONLY); } else { return connection.prepareCall(sql); } } @Override public void parameterize(Statement statement) throws SQLException { registerOutputParameters((CallableStatement) statement); parameterHandler.setParameters((CallableStatement) statement); } @Override public int update(Statement statement) throws SQLException { CallableStatement cs = (CallableStatement) statement; cs.execute(); int rows = cs.getUpdateCount(); Object parameterObject = boundSql.getParameterObject(); KeyGenerator keyGenerator = mappedStatement.getKeyGenerator(); keyGenerator.processAfter(executor, mappedStatement, cs, parameterObject); resultSetHandler.handleOutputParameters(cs); return rows; } @Override public void batch(Statement statement) throws SQLException { CallableStatement cs = (CallableStatement) statement; cs.addBatch(); } @Override public <E> List<E> query(Statement statement, ResultHandler resultHandler) throws SQLException { CallableStatement cs = (CallableStatement) statement; cs.execute(); List<E> resultList = resultSetHandler.<E>handleResultSets(cs); resultSetHandler.handleOutputParameters(cs); return resultList; } @Override public <E> Cursor<E> queryCursor(Statement statement) throws SQLException { CallableStatement cs = (CallableStatement) statement; cs.execute(); Cursor<E> resultList = resultSetHandler.<E>handleCursorResultSets(cs); resultSetHandler.handleOutputParameters(cs); return resultList; }
RoutingStatementHandler
根据语句类型,自动路由到正确的语句处理器。
public RoutingStatementHandler(Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) { switch (ms.getStatementType()) { case STATEMENT: delegate = new SimpleStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql); break; case PREPARED: delegate = new PreparedStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql); break; case CALLABLE: delegate = new CallableStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql); break; default: throw new ExecutorException("Unknown statement type: " + ms.getStatementType()); } }
时间: 2024-10-26 04:38:56