1.flink sql 解析

方法1：直接创建 flink sql parser 解析多行 sql

<dependency>
    <groupId>org.apache.flink</groupId>
    <artifactId>flink-sql-parser</artifactId>
    <version>1.12.3</version>
<dependency>

        SqlParser sqlParser = SqlParser.create(sql, SqlParser.config()
                .withParserFactory(FlinkSqlParserImpl.FACTORY)
                .withQuoting(Quoting.BACK_TICK)
                .withUnquotedCasing(Casing.TO_LOWER)
                .withQuotedCasing(Casing.UNCHANGED)
                .withConformance(FlinkSqlConformance.DEFAULT)
        );
        SqlNodeList sqlNodeList = sqlParser.parseStmtList();
        List<SqlNode> sqlNodes = sqlNodeList.getList();
        for (SqlNode sqlNode : sqlNodes) {
            switch (sqlNode.getKind()) {
                case INSERT:
                    SqlNodeList targetColumnNodes = ((SqlInsert) sqlNode).getTargetColumnList();
                    // todo
                    break;
                case SELECT:
                    SqlNodeList nodes = ((SqlSelect) sqlNode).getSelectList();
                    // todo
                    break;
                case XXX:
                    // todo 
                default:
                    // ignore
            }
        }

方法2：通过 table env 获取的 flink sql parser 解析单行 sql

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-table-api-java-bridge_2.11</artifactId>
            <version>1.12.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-table-api-scala-bridge_2.11</artifactId>
            <version>1.12.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-table-planner_2.11</artifactId>
            <version>1.12.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-table-planner-blink_2.11</artifactId>
            <version>1.12.3</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-scala_2.11</artifactId>
            <version>1.12.3</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients_2.11</artifactId>
            <version>1.12.3</version>
        </dependency>

//1. 先创建ExecutionEnvironment
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
EnvironmentSettings settings = EnvironmentSettings.newInstance()
    .useBlinkPlanner()
    .inStreamingMode()
    .build();

tableEnv = StreamTableEnvironment.create(env, settings);
//2. 从这个TableEnv中获取ParserImpl
Parser parserImpl = ((TableEnvironmentImpl) tableEnv).getParser();
// parse the sql
SqlNode sqlNode = parserImpl.parse(statement);
// todo
if(sqlNode.getKind() == SELECT){
// ...
}

2.flink sql 校验

参考 flink sql 单条 sql 校验和上下文校验源码

// 单条 sql 校验
// ParserImpl parse
    @Override
    public List<Operation> parse(String statement) {
        //...省略
        // 单条 sql 校验
        Operation operation =
                SqlToOperationConverter.convert(planner, catalogManager, parsed)
                        .orElseThrow(() -> new TableException("Unsupported query: " + statement));
        return Collections.singletonList(operation);
    }

// 上下文校验
// 1.TableEnvironmentImpl executeSql
    @Override
    public TableResult executeSql(String statement) {
        List<Operation> operations = parser.parse(statement);

        if (operations.size() != 1) {
            throw new TableException(UNSUPPORTED_QUERY_IN_EXECUTE_SQL_MSG);
        }

        return executeOperation(operations.get(0));
    }

    // 2.TableEnvironmentImpl executeOperation
    // 最关键是catalogManager，用于管理table，例如创建、删除等
    private TableResult executeOperation(Operation operation) {
        if (operation instanceof ModifyOperation) {
            return executeInternal(Collections.singletonList((ModifyOperation) operation));
        } else if (operation instanceof CreateTableOperation) {
            CreateTableOperation createTableOperation = (CreateTableOperation) operation;
            if (createTableOperation.isTemporary()) {
                catalogManager.createTemporaryTable(
                        createTableOperation.getCatalogTable(),
                        createTableOperation.getTableIdentifier(),
                        createTableOperation.isIgnoreIfExists());
            } else {
                catalogManager.createTable(
                        createTableOperation.getCatalogTable(),
                        createTableOperation.getTableIdentifier(),
                        createTableOperation.isIgnoreIfExists());
            }
            return TableResultImpl.TABLE_RESULT_OK;
        } else if (operation instanceof DropTableOperation) {
            DropTableOperation dropTableOperation = (DropTableOperation) operation;
            if (dropTableOperation.isTemporary()) {
                catalogManager.dropTemporaryTable(
                        dropTableOperation.getTableIdentifier(), dropTableOperation.isIfExists());
            } else {
                catalogManager.dropTable(
                        dropTableOperation.getTableIdentifier(), dropTableOperation.isIfExists());
            }
            return TableResultImpl.TABLE_RESULT_OK;
        }
     ...省略
     }

问题1：如何获取 Planner 和 CatalogManager，进而利用 SqlToOperationConverter 校验单个 sqlNode？
问题2：如何进行 sql 上下文校验？

// 通过 table env 获取 Planner 和 CatalogManager
CatalogManager catalogManager = ((TableEnvironmentImpl) tableEnv).getCatalogManager();
StreamPlanner planner = (StreamPlanner) ((TableEnvironmentImpl) tableEnv).getPlanner();

//创建 flink planner 实例
FlinkPlannerImpl flinkPlanner = planner.createFlinkPlanner();

// 校验单条 sqlNode
Operation operation = SqlToOperationConverter.convert(planner, catalogManager, sqlNode).get()

        // 上下文校验
        // 参考 TableEnvironmentImpl executeOperation
        if (operation instanceof ModifyOperation) {
            //...省略
        } else if (operation instanceof CreateTableOperation) {
            CreateTableOperation createTableOperation = (CreateTableOperation) operation;
            if (createTableOperation.isTemporary()) {
                catalogManager.createTemporaryTable(
                        createTableOperation.getCatalogTable(),
                        createTableOperation.getTableIdentifier(),
                        createTableOperation.isIgnoreIfExists());
            } else {
                catalogManager.createTable(
                        createTableOperation.getCatalogTable(),
                        createTableOperation.getTableIdentifier(),
                        createTableOperation.isIgnoreIfExists());
            }
        } else if (operation instanceof DropTableOperation) {
            DropTableOperation dropTableOperation = (DropTableOperation) operation;
            if (dropTableOperation.isTemporary()) {
                catalogManager.dropTemporaryTable(
                        dropTableOperation.getTableIdentifier(), dropTableOperation.isIfExists());
            } else {
                catalogManager.dropTable(
                        dropTableOperation.getTableIdentifier(), dropTableOperation.isIfExists());
            }
        } 
     //...省略