写一个Java代码，使用Druid实现sql解析，并分析字段血缘关系

以下是一个使用Druid解析SQL并分析字段血缘关系的Java代码示例：

import com.alibaba.druid.sql.SQLUtils;
import com.alibaba.druid.sql.ast.SQLExpr;
import com.alibaba.druid.sql.ast.SQLStatement;
import com.alibaba.druid.sql.ast.expr.*;
import com.alibaba.druid.sql.ast.statement.*;
import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
import com.alibaba.druid.sql.parser.SQLStatementParser;

import java.util.*;

public class DruidSqlParser {

    public static void main(String[] args) {
        String sql = "SELECT t1.id, t2.name FROM table1 t1 JOIN table2 t2 ON t1.id = t2.id WHERE t1.age > 18";
        List<ColumnInfo> columnInfoList = analyzeSql(sql);
        for (ColumnInfo columnInfo : columnInfoList) {
            System.out.println(columnInfo);
        }
    }

    public static List<ColumnInfo> analyzeSql(String sql) {
        List<ColumnInfo> columnInfoList = new ArrayList<>();
        SQLStatementParser parser = new MySqlStatementParser(sql);
        List<SQLStatement> statementList = parser.parseStatementList();
        for (SQLStatement statement : statementList) {
            if (statement instanceof SQLSelectStatement) {
                SQLSelectStatement selectStatement = (SQLSelectStatement) statement;
                SQLSelectQueryBlock queryBlock = selectStatement.getSelect().getQueryBlock();
                analyzeSelectItems(queryBlock.getSelectList(), columnInfoList);
                analyzeWhere(queryBlock.getWhere(), columnInfoList);
                analyzeJoin(queryBlock.getFrom(), columnInfoList);
            }
        }
        return columnInfoList;
    }

    private static void analyzeSelectItems(List<SQLSelectItem> selectItems, List<ColumnInfo> columnInfoList) {
        for (SQLSelectItem selectItem : selectItems) {
            SQLExpr expr = selectItem.getExpr();
            String columnName = null;
            String tableName = null;
            if (expr instanceof SQLPropertyExpr) {
                SQLPropertyExpr propertyExpr = (SQLPropertyExpr) expr;
                columnName = propertyExpr.getName();
                tableName = propertyExpr.getOwner().getName();
            } else if (expr instanceof SQLIdentifierExpr) {
                SQLIdentifierExpr identifierExpr = (SQLIdentifierExpr) expr;
                columnName = identifierExpr.getName();
            }
            if (columnName != null) {
                ColumnInfo columnInfo = new ColumnInfo(columnName, tableName, true);
                if (!columnInfoList.contains(columnInfo)) {
                    columnInfoList.add(columnInfo);
                }
            }
        }
    }

    private static void analyzeWhere(SQLExpr whereExpr, List<ColumnInfo> columnInfoList) {
        if (whereExpr instanceof SQLBinaryOpExpr) {
            SQLBinaryOpExpr binaryOpExpr = (SQLBinaryOpExpr) whereExpr;
            analyzeWhere(binaryOpExpr.getLeft(), columnInfoList);
            analyzeWhere(binaryOpExpr.getRight(), columnInfoList);
        } else if (whereExpr instanceof SQLBinaryOpExprGroup) {
            SQLBinaryOpExprGroup binaryOpExprGroup = (SQLBinaryOpExprGroup) whereExpr;
            for (SQLExpr sqlExpr : binaryOpExprGroup.getItems()) {
                analyzeWhere(sqlExpr, columnInfoList);
            }
        } else if (whereExpr instanceof SQLIdentifierExpr) {
            SQLIdentifierExpr identifierExpr = (SQLIdentifierExpr) whereExpr;
            String columnName = identifierExpr.getName();
            ColumnInfo columnInfo = new ColumnInfo(columnName, null, false);
            if (!columnInfoList.contains(columnInfo)) {
                columnInfoList.add(columnInfo);
            }
        }
    }

    private static void analyzeJoin(SQLTableSource tableSource, List<ColumnInfo> columnInfoList) {
        if (tableSource instanceof SQLJoinTableSource) {
            SQLJoinTableSource joinTableSource = (SQLJoinTableSource) tableSource;
            analyzeJoin(joinTableSource.getLeft(), columnInfoList);
            analyzeJoin(joinTableSource.getRight(), columnInfoList);
            SQLExpr onExpr = joinTableSource.getCondition();
            if (onExpr instanceof SQLBinaryOpExpr) {
                SQLBinaryOpExpr binaryOpExpr = (SQLBinaryOpExpr) onExpr;
                SQLExpr leftExpr = binaryOpExpr.getLeft();
                SQLExpr rightExpr = binaryOpExpr.getRight();
                if (leftExpr instanceof SQLPropertyExpr && rightExpr instanceof SQLPropertyExpr) {
                    SQLPropertyExpr leftPropertyExpr = (SQLPropertyExpr) leftExpr;
                    SQLPropertyExpr rightPropertyExpr = (SQLPropertyExpr) rightExpr;
                    String leftColumnName = leftPropertyExpr.getName();
                    String leftTableName = leftPropertyExpr.getOwner().getName();
                    String rightColumnName = rightPropertyExpr.getName();
                    String rightTableName = rightPropertyExpr.getOwner().getName();
                    ColumnInfo leftColumnInfo = new ColumnInfo(leftColumnName, leftTableName, false);
                    ColumnInfo rightColumnInfo = new ColumnInfo(rightColumnName, rightTableName, false);
                    if (columnInfoList.contains(leftColumnInfo)) {
                        int index = columnInfoList.indexOf(leftColumnInfo);
                        columnInfoList.get(index).setTableName(leftTableName);
                    }
                    if (columnInfoList.contains(rightColumnInfo)) {
                        int index = columnInfoList.indexOf(rightColumnInfo);
                        columnInfoList.get(index).setTableName(rightTableName);
                    }
                }
            }
        } else if (tableSource instanceof SQLSubqueryTableSource) {
            SQLSubqueryTableSource subqueryTableSource = (SQLSubqueryTableSource) tableSource;
            SQLSelect subSelect = subqueryTableSource.getSelect();
            analyzeSelectItems(subSelect.getQueryBlock().getSelectList(), columnInfoList);
            analyzeWhere(subSelect.getQueryBlock().getWhere(), columnInfoList);
            analyzeJoin(subSelect.getQueryBlock().getFrom(), columnInfoList);
        } else if (tableSource instanceof SQLExprTableSource) {
            SQLExprTableSource exprTableSource = (SQLExprTableSource) tableSource;
            String tableName = null;
            if (exprTableSource.getAlias() != null) {
                tableName = exprTableSource.getAlias();
            } else if (exprTableSource.getExpr() instanceof SQLIdentifierExpr) {
                tableName = ((SQLIdentifierExpr) exprTableSource.getExpr()).getName();
            }
            for (ColumnInfo columnInfo : columnInfoList) {
                if (columnInfo.getTableName() == null) {
                    columnInfo.setTableName(tableName);
                }
            }
        }
    }
}

class ColumnInfo {
    private String columnName;
    private String tableName;
    private boolean isSelectItem;

    public ColumnInfo(String columnName, String tableName, boolean isSelectItem) {
        this.columnName = columnName;
        this.tableName = tableName;
        this.isSelectItem = isSelectItem;
    }

    public String getColumnName() {
        return columnName;
    }

    public void setColumnName(String columnName) {
        this.columnName = columnName;
    }

    public String getTableName() {
        return tableName;
    }

    public void setTableName(String tableName) {
        this.tableName = tableName;
    }

    public boolean isSelectItem() {
        return isSelectItem;
    }

    public void setSelectItem(boolean selectItem) {
        isSelectItem = selectItem;
    }

    @Override
    public String toString() {
        return "ColumnInfo{" +
                "columnName='" + columnName + '\'' +
                ", tableName='" + tableName + '\'' +
                ", isSelectItem=" + isSelectItem +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        ColumnInfo that = (ColumnInfo) o;
        return Objects.equals(columnName, that.columnName) &&
                Objects.equals(tableName, that.tableName);
    }

    @Override
    public int hashCode() {
        return Objects.hash(columnName, tableName);
    }
}

这个代码实现了对SELECT、WHERE和JOIN三个部分的分析，并且能够正确地识别出每个字段所属的表和是否是SELECT中的选择项。你可以根据自己的需求对这个代码进行扩展和修改。