组件学习

KeyGenerator

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ResultHandler

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BaseBuilder

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SqlNode

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TokenHandler

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ResultSetHandler

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StatementHandler

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PreparedStatementHandler

public List query(Statement statement, ResultHandler resultHandler)
      throws SQLException {
    PreparedStatement ps = (PreparedStatement) statement;
    // 看到了熟悉的jdbc的代码 ：）
    ps.execute();

    //resultSetHandler 处理返回结果
    return resultSetHandler.handleResultSets(ps);
  }

Cache

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plugin 钩子

interceptorChain.pluginAll(statementHandler)

public StatementHandler newStatementHandler(Executor executor, MappedStatement mappedStatement, Object parameterObject, RowBounds rowBounds, ResultHandler resultHandler) {
    StatementHandler statementHandler = new RoutingStatementHandler(executor, mappedStatement, parameterObject, rowBounds, resultHandler);
    statementHandler = (StatementHandler) interceptorChain.pluginAll(statementHandler);
    return statementHandler;
  }

SimpleExecutor

public int doUpdate(MappedStatement ms, Object parameter)
      throws SQLException {
    Statement stmt = null;
    try {
      Configuration configuration = ms.getConfiguration();
      StatementHandler handler = configuration.newStatementHandler(this, ms, parameter, RowBounds.DEFAULT, null);
      stmt = prepareStatement(handler);
      return handler.update(stmt);
    } finally {
      closeStatement(stmt);
    }
  }

  public List doQuery(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler) throws SQLException {
    Statement stmt = null;
    try {
      Configuration configuration = ms.getConfiguration();
      StatementHandler handler = configuration.newStatementHandler(this, ms, parameter, rowBounds, resultHandler);
      stmt = prepareStatement(handler);
      return handler.query(stmt, resultHandler);
    } finally {
      closeStatement(stmt);
    }
  }

开始调用到jdbc 操作

• class::BaseStatementHandler

public Statement prepare(Connection connection)
      throws SQLException {
    ErrorContext.instance().sql(boundSql.getSql());
    Statement statement = null;
    try {
      statement = instantiateStatement(connection);
      setStatementTimeout(statement);
      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);
    }
  }

TypeDiscriminator 类型鉴别器

调用堆栈

• selectOne

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