–>  对象或类间调用
->  对象或类内调用
[]  方法本身或方法体补充说明
=>  值变化
==  类型相同     === 值相等
«< 回到方法的被调用链某处继续向下执行

Insert ： org/springframework/jdbc/datasource/DataSourceTransactionManager.doBegin –> this.dataSource.getConnection()
–> io/shardingjdbc/core/jdbc/core/datasource/ShardingDataSource.getConnection –> new ShardingConnection(shardingContext)

org/apache/ibatis/binding/MapperMethod.execute [case INSERT]
[org/apache/ibatis/session/Configuration.newExecutor : executor = new CachingExecutor(executor);]
–> org/mybatis/spring/SqlSessionTemplate.insert -> SqlSessionInterceptor.invoke - invoke –> sun/reflect/NativeMethodAccessorImpl.invoke0
–> org/apache/ibatis/executor/CachingExecutor.update [delegate==SimpleExecutor]
–> org/apache/ibatis/executor/BaseExecutor.update(MappedStatement ms, Object parameter)
–> org/apache/ibatis/executor/SimpleExecutor.[abstract]doUpdate(ms, parameter) ->prepareStatement(StatementHandler handler, Log statementLog) :
Connection connection = getConnection(statementLog);
stmt = handler.prepare(connection, transaction.getTimeout());
       这个connection根据开头可知是ShardingConnection类型     –> org/apache/ibatis/executor/statement/RoutingStatementHandler.prepare (delegate==PreparedStatementHandler)
–> org/apache/ibatis/executor/statement/BaseStatementHandler.prepare->[abstract]instantiateStatement
–> org/apache/ibatis/executor/statement/PreparedStatementHandler.instantiateStatement
–> io/shardingjdbc/core/jdbc/core/connection/ShardingConnection.prepareStatement(final String sql):

---

@Override     
public PreparedStatement prepareStatement(final String sql) throws SQLException {     
    return new ShardingPreparedStatement(this, sql);     
}  

public ShardingPreparedStatement(final ShardingConnection connection, final String sql) {     
    this(connection, sql, ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY, ResultSet.HOLD_CURSORS_OVER_COMMIT);     
}     

public ShardingPreparedStatement(final ShardingConnection connection, final String sql, final int resultSetType, final int resultSetConcurrency, final int resultSetHoldability) {
    this.connection = connection;
    this.resultSetType = resultSetType;
    this.resultSetConcurrency = resultSetConcurrency;
    this.resultSetHoldability = resultSetHoldability;
    routingEngine = new PreparedStatementRoutingEngine(sql, connection.getShardingContext());
}

---

public ShardingPreparedStatement(final ShardingConnection connection, final String sql, final int resultSetType, final int resultSetConcurrency, final int resultSetHoldability) {
    this.connection = connection;
    this.resultSetType = resultSetType;
    this.resultSetConcurrency = resultSetConcurrency;
    this.resultSetHoldability = resultSetHoldability;
    routingEngine = new PreparedStatementRoutingEngine(sql, connection.getShardingContext());
}

public PreparedStatementRoutingEngine(final String logicSQL, final ShardingContext shardingContext) {
    this.logicSQL = logicSQL;
    sqlRouter = SQLRouterFactory.createSQLRouter(shardingContext);
}

public static SQLRouter createSQLRouter(final ShardingContext shardingContext) {
    return HintManagerHolder.isDatabaseShardingOnly() ? new DatabaseHintSQLRouter(shardingContext) : new ParsingSQLRouter(shardingContext);
}

public ParsingSQLRouter(final ShardingContext shardingContext) {
    shardingRule = shardingContext.getShardingRule();
    databaseType = shardingContext.getDatabaseType();
    showSQL = shardingContext.isShowSQL();
    generatedKeys = new LinkedList<>();
}

---

sql和路由规则都有了     回到 «< org/apache/ibatis/executor/statement/BaseStatementHandler.prepare->setFetchSize(statement)
«< org/apache/ibatis/executor/SimpleExecutor.prepareStatement:handler.parameterize(stmt : stmt==ShardingPreparedStatement)
–> org/apache/ibatis/executor/statement/RoutingStatementHandler.parameterize
–> org/apache/ibatis/executor/statement/PreparedStatementHandler.parameterize
«< org/apache/ibatis/executor/SimpleExecutor.doUpdate : return handler.update(stmt);
–> org/apache/ibatis/executor/statement/PreparedStatementHandler.update(statement==ShardingPreparedStatement) :

---

    @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;
    }

---

ps.execute == io/shardingjdbc/core/jdbc/core/statement/ShardingPreparedStatement.execute:

---

@Override
public boolean execute() throws SQLException {
    try {
        Collection<PreparedStatementUnit> preparedStatementUnits = route();
        return new PreparedStatementExecutor(
                getConnection().getShardingContext().getExecutorEngine(), routeResult.getSqlStatement().getType(), preparedStatementUnits, getParameters()).execute();
    } finally {
        clearBatch();
    }
}

private Collection<PreparedStatementUnit> route() throws SQLException {
    Collection<PreparedStatementUnit> result = new LinkedList<>();
    routeResult = routingEngine.route(getParameters());
    for (SQLExecutionUnit each : routeResult.getExecutionUnits()) {
        SQLType sqlType = routeResult.getSqlStatement().getType();
        Collection<PreparedStatement> preparedStatements;
        if (SQLType.DDL == sqlType) {
            preparedStatements = generatePreparedStatementForDDL(each);
        } else {
            preparedStatements = Collections.singletonList(generatePreparedStatement(each));
        }
        routedStatements.addAll(preparedStatements);
        for (PreparedStatement preparedStatement : preparedStatements) {
            replaySetParameter(preparedStatement);
            result.add(new PreparedStatementUnit(each, preparedStatement));
        }
    }
    return result;
}

---

–> io/shardingjdbc/core/routing/PreparedStatementRoutingEngine.route:

---

public SQLRouteResult route(final List<Object> parameters) {
    if (null == sqlStatement) {
        sqlStatement = sqlRouter.parse(logicSQL, parameters.size());
    }
    return sqlRouter.route(logicSQL, parameters, sqlStatement);
}

---

io/shardingjdbc/core/routing/router/ParsingSQLRouter.parse [例:logicSQL=insert into aaatest(a,b,c) values(?,?,?), parameters=1,1,1] :

---

@Override
public SQLStatement parse(final String logicSQL, final int parametersSize) {
    SQLParsingEngine parsingEngine = new SQLParsingEngine(databaseType, logicSQL, shardingRule); [databaseType==MySQL]
    SQLStatement result = parsingEngine.parse();
    if (result instanceof InsertStatement) {
        ((InsertStatement) result).appendGenerateKeyToken(shardingRule, parametersSize);
    }
    return result;
}

---

io/shardingjdbc/core/parsing/SQLParsingEngine.parse[lexer:词法分析器]：

---

    public SQLStatement parse() {
            LexerEngine lexerEngine = LexerEngineFactory.newInstance(dbType, sql);
            lexerEngine.nextToken();
            return SQLParserFactory.newInstance(dbType, lexerEngine.getCurrentToken().getType(), shardingRule, lexerEngine).parse();
    }

    public MySQLLexer(final String input) {
            super(input, dictionary);
    }

    public final void nextToken() {
            skipIgnoredToken();
            if (isVariableBegin()) {
                currentToken = new Tokenizer(input, dictionary, offset).scanVariable();
            } else if (isNCharBegin()) {
                currentToken = new Tokenizer(input, dictionary, ++offset).scanChars();
            } else if (isIdentifierBegin()) {
                currentToken = new Tokenizer(input, dictionary, offset).scanIdentifier();
            } else if (isHexDecimalBegin()) {
                currentToken = new Tokenizer(input, dictionary, offset).scanHexDecimal();
            } else if (isNumberBegin()) {
                currentToken = new Tokenizer(input, dictionary, offset).scanNumber();
            } else if (isSymbolBegin()) {
                currentToken = new Tokenizer(input, dictionary, offset).scanSymbol();
            } else if (isCharsBegin()) {
                currentToken = new Tokenizer(input, dictionary, offset).scanChars();
            } else if (isEnd()) {
                currentToken = new Token(Assist.END, "", offset);
            } else {
                throw new SQLParsingException(this, Assist.ERROR);
            }
            offset = currentToken.getEndPosition();
    }

---

–> io/shardingjdbc/core/parsing/lexer/analyzer/Tokenizer.scanIdentifier 截出Token，例如INSERT
«< io/shardingjdbc/core/parsing/parser/sql/SQLParserFactory.newInstance:    

---

public static SQLParser newInstance(final DatabaseType dbType, final TokenType tokenType, final ShardingRule shardingRule, final LexerEngine lexerEngine) {
    if (!(tokenType instanceof DefaultKeyword)) {
        throw new SQLParsingUnsupportedException(tokenType);
    }
    switch ((DefaultKeyword) tokenType)  {
        case SELECT:
            return SelectParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        case INSERT:
            return InsertParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        case UPDATE:
            return UpdateParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        case DELETE:
            return DeleteParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        case CREATE:
            return CreateParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        case ALTER:
            return AlterParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        case DROP:
            return DropParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        case TRUNCATE:
            return TruncateParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        case SET:
        case COMMIT:
        case ROLLBACK:
        case SAVEPOINT:
        case BEGIN:
            return TCLParserFactory.newInstance(dbType, shardingRule, lexerEngine);
        default:
            throw new SQLParsingUnsupportedException(lexerEngine.getCurrentToken().getType());
    }
}

---

这个例子是INSERT。 –> io/shardingjdbc/core/parsing/parser/sql/dml/insert/InsertParserFactory.newInstance
–> return new MySQLInsertParser(shardingRule, lexerEngine);
–> io/shardingjdbc/core/parsing/parser/dialect/mysql/clause/facade/MySQLInsertClauseParserFacade
–> io/shardingjdbc/core/parsing/parser/dialect/mysql/clause/MySQLTableReferencesClauseParser
aliasExpressionParser === io/shardingjdbc/core/parsing/parser/dialect/ExpressionParserFactory.createAliasExpressionParser [return new MySQLAliasExpressionParser(lexerEngine);basicExpressionParser === io/shardingjdbc/core/parsing/parser/dialect/ExpressionParserFactory.createBasicExpressionParser]
«< MySQLInsertClauseParserFacade –> io/shardingjdbc/core/parsing/parser/dialect/mysql/clause/MySQLInsertValuesClauseParser : basicExpressionParser
«< MySQLInsertClauseParserFacade –> io/shardingjdbc/core/parsing/parser/dialect/mysql/clause/MySQLInsertSetClauseParser

回到上面SQLParsingEngine.parse 方法中 InsertParserFactory.newInstance 之后还有个链式的parse调用[return SQLParserFactory.newInstance(dbType, lexerEngine.getCurrentToken().getType(), shardingRule, lexerEngine).parse();]
–> io/shardingjdbc/core/parsing/parser/sql/dml/insert/AbstractInsertParser.parse :

---

@Override
public final DMLStatement parse() {
    lexerEngine.nextToken();
    InsertStatement result = new InsertStatement();
    insertClauseParserFacade.getInsertIntoClauseParser().parse(result);
    insertClauseParserFacade.getInsertColumnsClauseParser().parse(result);
    if (lexerEngine.equalAny(DefaultKeyword.SELECT, Symbol.LEFT_PAREN)) {
        throw new UnsupportedOperationException("Cannot INSERT SELECT");
    }
    insertClauseParserFacade.getInsertValuesClauseParser().parse(result);
    insertClauseParserFacade.getInsertSetClauseParser().parse(result);
    appendGenerateKey(result);
    return result;
}

---

–> io/shardingjdbc/core/parsing/parser/clause/InsertIntoClauseParser :

---

public void parse(final InsertStatement insertStatement) {
    lexerEngine.unsupportedIfEqual(getUnsupportedKeywordsBeforeInto());
    lexerEngine.skipUntil(DefaultKeyword.INTO);
    lexerEngine.nextToken();
    tableReferencesClauseParser.parse(insertStatement, true);
    skipBetweenTableAndValues(insertStatement);
}

---

–> io/shardingjdbc/core/parsing/parser/clause/TableReferencesClauseParser

---

public final void parse(final SQLStatement sqlStatement, final boolean isSingleTableOnly) {
    do {
        parseTableReference(sqlStatement, isSingleTableOnly);
    } while (lexerEngine.skipIfEqual(Symbol.COMMA));
}

---

–> io/shardingjdbc/core/parsing/parser/dialect/mysql/clause/MySQLTableReferencesClauseParser

---

@Override
protected void parseTableReference(final SQLStatement sqlStatement, final boolean isSingleTableOnly) {
    parseTableFactor(sqlStatement, isSingleTableOnly);
    parsePartition();
    parseIndexHint(sqlStatement);
}

---

–> io/shardingjdbc/core/parsing/parser/clause/TableReferencesClauseParser.parseTableFactor 先根据当前token的偏移量截出literals，这个例子里就是表名，于是当前token从into变成LEFT_PAREN就是左括号， 判断as什么的，还有一堆key没细看 ->parseJoinTable->parseJoinType匹配与多表连接相关的9个关键字，因为是insert并没有，所以这里连表的相关逻辑没有走 ->parseIndexHint判断是否包含USE、IGNORE、FORCE关键字，如果用跳过，同时跳过相关的INDEX, KEY, FOR, JOIN, ORDER, GROUP, BY关键字 跳过方法是通过lexer.nextToken()；我这里不包含这几个关键字，如果包含还会处理跳过括号，同时处理语句中的?，计入参数数量，截取括号内列的逻辑。

«< io/shardingjdbc/core/parsing/parser/clause/TableReferencesClauseParser.parse while判断应该是对(…),(…)情况的处理

«< io/shardingjdbc/core/parsing/parser/clause/InsertIntoClauseParser.parse -> skipBetweenTableAndValues

«< io/shardingjdbc/core/parsing/parser/sql/dml/insert/AbstractInsertParser.parse
–> io/shardingjdbc/core/parsing/parser/clause/InsertColumnsClauseParser.parse  取出所有列（会检查shardingrule配置）加入insertStatement对象
–>io/shardingjdbc/core/parsing/parser/clause/InsertValuesClauseParser.parse ->parseValues –>io/shardingjdbc/core/parsing/parser/clause/expression/BasicExpressionParser.parse ->parseExpression 判断”？”或具体的数据类型，创建对应的SQLExpression 根据列生成Condition并和shardingRule加入insertStatement对象，如果循环的列是主键将则:insertStatement.setGeneratedKey(createGeneratedKey(each, sqlExpression))
«< InsertValuesClauseParser.parse 如果是(…),(…)情况，调用parseMultipleValues处理
«< AbstractInsertParser.parse –> io/shardingjdbc/core/parsing/parser/clause/InsertSetClauseParser.parse Insert还有一种set c=v,c=v…的写法，这里是处理这个写法的
«< AbstractInsertParser.parse -> appendGenerateKey «< io/shardingjdbc/core/routing/PreparedStatementRoutingEngine.route –> io/shardingjdbc/core/routing/router/ParsingSQLRouter.route 根据表数量和语句类型使用用不同的routingEngine进行路由，如果有配置cn.tellwhy.support.test.service.sharding.ShardingKeyGenerator，会生成自定义key -> processGeneratedKey
由于我这就是一个简单的insert所以–> io/shardingjdbc/core/routing/type/simple/SimpleRoutingEngine.route
先获取tableRule，就是配置的那些，这个sql表对应了哪些库的哪些表 然后获取databaseShardingValues和tableShardingValues库和表的分片键 -> routeDataSources 获取目标数据库 -> routeTables 获取目标表名 routeDataSources × routeTables两层循环合成数据节点：库名.表名 -> generateRoutingResult «< ParsingSQLRouter.ParsingSQLRouter 通过SQLRewriteEngine将对应逻辑表和物理表做对应SQLRewriteEngine.getTableTokens –> io/shardingjdbc/core/rewrite/SQLBuilder.toSQL 替换表 «< ParsingSQLRouter.route 将替换好的所有sql放入SQLRouteResult中返回 «< io/shardingjdbc/core/jdbc/core/statement/ShardingPreparedStatement.route 循环SQLRouteResult的所有SQLExecutionUnit each：-> generatePreparedStatement:[创建每个sql对应的数据源连接]

---

private PreparedStatement generatePreparedStatement(final SQLExecutionUnit sqlExecutionUnit) throws SQLException {
    Connection connection = getConnection().getConnection(sqlExecutionUnit.getDataSource(), routeResult.getSqlStatement().getType());
    return returnGeneratedKeys ? connection.prepareStatement(sqlExecutionUnit.getSql(), Statement.RETURN_GENERATED_KEYS)
            : connection.prepareStatement(sqlExecutionUnit.getSql(), resultSetType, resultSetConcurrency, resultSetHoldability);
}

---

public Connection getConnection(final String dataSourceName, final SQLType sqlType) throws SQLException {
    if (getCachedConnections().containsKey(dataSourceName)) {
        return getCachedConnections().get(dataSourceName);
    }
    DataSource dataSource = shardingContext.getShardingRule().getDataSourceMap().get(dataSourceName);
    Preconditions.checkState(null != dataSource, "Missing the rule of %s in DataSourceRule", dataSourceName);
    String realDataSourceName;
    if (dataSource instanceof MasterSlaveDataSource) {
        NamedDataSource namedDataSource = ((MasterSlaveDataSource) dataSource).getDataSource(sqlType);
        realDataSourceName = namedDataSource.getName();
        if (getCachedConnections().containsKey(realDataSourceName)) {
            return getCachedConnections().get(realDataSourceName);
        }
        dataSource = namedDataSource.getDataSource();
    } else {
        realDataSourceName = dataSourceName;
    }
    Connection result = dataSource.getConnection();
    getCachedConnections().put(realDataSourceName, result);
    replayMethodsInvocation(result);
    return result;
}

---

«< generatePreparedStatement –> com/alibaba/druid/pool/DruidPooledConnection.prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) «< ShardingPreparedStatement.route –> io/shardingjdbc/core/jdbc/adapter/AbstractShardingPreparedStatementAdapter.replaySetParameter –> io/shardingjdbc/core/jdbc/adapter/invocation/JdbcMethodInvocation.invoke –> com/alibaba/druid/pool/DruidPooledPreparedStatement.setInt [因为我用的sql参数类型是int] JdbcMethodInvocation.invoke : [.target ** NOT SPECIFIED ** => 1 com.mysql.jdbc.JDBC4PreparedStatement@hashcode: insert into **_0(,,) values(1,** NOT SPECIFIED , NOT SPECIFIED **)]

SQLExecutionUnit each end «< route 返回笛卡尔积个元素的Collection <<< execute --> io/shardingjdbc/core/executor/type/prepared/PreparedStatementExecutor.execute [PreparedStatementExecutor.execute.execute] --> io/shardingjdbc/core/executor/ExecutorEngine.execute 用baseStatementUnits(PreparedStatementUnit)创建OverallExecutionEvent，发给事件总线 --> com/google/common/eventbus/EventBus.post

ExecutorEngine.execute [这里可以看出来，先用iterator.next()拆除第一个执行单元，将剩下的提交给ExecutorService，当前线程执行一个，然后restFutures.get()回子线程结果，将当前线程结果与子线程结果合成一个LinkedList]:

---

private  <T> List<T> execute(
        final SQLType sqlType, final Collection<? extends BaseStatementUnit> baseStatementUnits, 
        final List<List<Object>> parameterSets, final ExecuteCallback<T> executeCallback) throws SQLException {
    if (baseStatementUnits.isEmpty()) {
        return Collections.emptyList();
    }
    OverallExecutionEvent event = new OverallExecutionEvent(sqlType, baseStatementUnits.size());
    EventBusInstance.getInstance().post(event);
    Iterator<? extends BaseStatementUnit> iterator = baseStatementUnits.iterator();
    BaseStatementUnit firstInput = iterator.next();
    ListenableFuture<List<T>> restFutures = asyncExecute(sqlType, Lists.newArrayList(iterator), parameterSets, executeCallback);
    T firstOutput;
    List<T> restOutputs;
    try {
        firstOutput = syncExecute(sqlType, firstInput, parameterSets, executeCallback);
        restOutputs = restFutures.get();
        //CHECKSTYLE:OFF
    } catch (final Exception ex) {
        //CHECKSTYLE:ON
        event.setException(ex);
        event.setEventExecutionType(EventExecutionType.EXECUTE_FAILURE);
        EventBusInstance.getInstance().post(event);
        ExecutorExceptionHandler.handleException(ex);
        return null;
    }
    event.setEventExecutionType(EventExecutionType.EXECUTE_SUCCESS);
    EventBusInstance.getInstance().post(event);
    List<T> result = Lists.newLinkedList(restOutputs);
    result.add(0, firstOutput);
    return result;
}

---

->asyncExecute –> io/shardingjdbc/core/executor/ExecutorEngine.executeInternal [PreparedStatementExecutor.execute.execute] 用用baseStatementUnits构建DMLExecutionEvent，发给事件总线 –> com/google/common/eventbus/EventBus.post –> io/shardingjdbc/core/executor/type/prepared/PreparedStatementExecutor.execute.execute[executorEngine.executePreparedStatement的@Override] –> com/alibaba/druid/pool/DruidPooledPreparedStatement.execute «< ExecutorEngine.executeInternal 发送成功事件 事件总线目前似乎只发现了BestEffortsDeliveryListener事务部分中了，其他功能没有发现，可能是用来加自定义监控的 «< asyncExecute :

---

private <T> ListenableFuture<List<T>> asyncExecute(
        final SQLType sqlType, final Collection<BaseStatementUnit> baseStatementUnits, final List<List<Object>> parameterSets, final ExecuteCallback<T> executeCallback) {
    List<ListenableFuture<T>> result = new ArrayList<>(baseStatementUnits.size());
    final boolean isExceptionThrown = ExecutorExceptionHandler.isExceptionThrown();
    final Map<String, Object> dataMap = ExecutorDataMap.getDataMap();
    for (final BaseStatementUnit each : baseStatementUnits) {
        result.add(executorService.submit(new Callable<T>() {
            
            @Override
            public T call() throws Exception {
                return executeInternal(sqlType, each, parameterSets, executeCallback, isExceptionThrown, dataMap);
            }
        }));
    }
    return Futures.allAsList(result);
}

---

特别记录一下，这里用于执行的executorService是com.google.common.util.concurrent.ListeningExecutorService

«< PreparedStatementExecutor.execute
从n个结果集里get了第一个结果返回
然后是clear包括参数，执行单元等 –> io/shardingjdbc/core/jdbc/core/statement/ShardingPreparedStatement.clearBatch    

«< org/apache/ibatis/executor/statement/PreparedStatementHandler.update «< org/apache/ibatis/executor/SimpleExecutor.doUpdate

Insert大致就这样了

---

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