java druid 递归解析包含若干个join语句的SQLSelect，替换其中的所有 * 元素，使用getTableColumns方法获取字段arrayList信息

可以借助JavaCC等工具来解析SQL语句，然后通过递归的方式遍历整个语法树，找到所有的SELECT语句，进而替换其中的“*”元素。

以下是一个简化的示例代码：

import java.util.ArrayList;
import java.util.List;
import net.sf.jsqlparser.JSQLParserException;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.parser.CCJSqlParserUtil;
import net.sf.jsqlparser.schema.Table;
import net.sf.jsqlparser.statement.Statement;
import net.sf.jsqlparser.statement.select.FromItem;
import net.sf.jsqlparser.statement.select.Join;
import net.sf.jsqlparser.statement.select.PlainSelect;
import net.sf.jsqlparser.statement.select.Select;
import net.sf.jsqlparser.statement.select.SelectBody;
import net.sf.jsqlparser.statement.select.SelectExpressionItem;
import net.sf.jsqlparser.statement.select.SelectItem;
import net.sf.jsqlparser.statement.select.SubSelect;

public class SQLParser {

    public static void main(String[] args) throws JSQLParserException {
        String sql = "SELECT t1.*, t2.col1, t3.col2 FROM table1 t1 "
                + "JOIN table2 t2 ON t1.id = t2.id "
                + "JOIN (SELECT id, col3 FROM table3) t3 ON t1.id = t3.id";
        Statement statement = CCJSqlParserUtil.parse(sql);
        if (statement instanceof Select) {
            Select select = (Select) statement;
            SelectBody selectBody = select.getSelectBody();
            replaceAllStarColumns(selectBody);
            List<TableColumn> columnList = getTableColumns(selectBody);
            System.out.println(columnList);
        }
    }

    private static void replaceAllStarColumns(SelectBody selectBody) {
        if (selectBody instanceof PlainSelect) {
            PlainSelect plainSelect = (PlainSelect) selectBody;
            List<SelectItem> selectItems = plainSelect.getSelectItems();
            for (int i = 0; i < selectItems.size(); i++) {
                SelectItem selectItem = selectItems.get(i);
                if (selectItem.toString().equals("*")) {
                    // Replace "*" with all columns of the table
                    FromItem fromItem = plainSelect.getFromItem();
                    if (fromItem instanceof Table) {
                        Table table = (Table) fromItem;
                        List<TableColumn> columns = getTableColumns(table);
                        selectItems.remove(i);
                        for (TableColumn column : columns) {
                            SelectExpressionItem expressionItem = new SelectExpressionItem();
                            expressionItem.setExpression(column.getColumnExpression());
                            selectItems.add(i++, expressionItem);
                        }
                    }
                }
            }
            if (plainSelect.getJoins() != null) {
                for (Join join : plainSelect.getJoins()) {
                    replaceAllStarColumns(join.getRightItem());
                }
            }
        } else if (selectBody instanceof SubSelect) {
            SubSelect subSelect = (SubSelect) selectBody;
            replaceAllStarColumns(subSelect.getSelectBody());
        }
    }

    private static List<TableColumn> getTableColumns(SelectBody selectBody) {
        List<TableColumn> columnList = new ArrayList<>();
        if (selectBody instanceof PlainSelect) {
            PlainSelect plainSelect = (PlainSelect) selectBody;
            List<SelectItem> selectItems = plainSelect.getSelectItems();
            for (SelectItem selectItem : selectItems) {
                if (selectItem instanceof SelectExpressionItem) {
                    SelectExpressionItem expressionItem = (SelectExpressionItem) selectItem;
                    Expression expression = expressionItem.getExpression();
                    if (expression instanceof net.sf.jsqlparser.schema.Column) {
                        net.sf.jsqlparser.schema.Column column = (net.sf.jsqlparser.schema.Column) expression;
                        columnList.add(new TableColumn(column.getTable().getName(), column.getColumnName()));
                    }
                }
            }
            if (plainSelect.getJoins() != null) {
                for (Join join : plainSelect.getJoins()) {
                    columnList.addAll(getTableColumns(join.getRightItem()));
                }
            }
        } else if (selectBody instanceof SubSelect) {
            SubSelect subSelect = (SubSelect) selectBody;
            columnList.addAll(getTableColumns(subSelect.getSelectBody()));
        }
        return columnList;
    }

    private static List<TableColumn> getTableColumns(Table table) {
        List<TableColumn> columnList = new ArrayList<>();
        // Get columns from database or cache
        // ...
        return columnList;
    }
}

class TableColumn {
    private String tableName;
    private String columnName;
    // Constructors and getters
    // ...
}

以上代码使用了JSqlParser库来解析SQL语句，并通过递归地遍历SELECT语句中的所有JOIN子句，替换其中的“*”元素，并使用getTableColumns方法获取字段arrayList信息。注意，getTableColumns方法需要根据实际情况从数据库或缓存中获取表的列信息。