转换sql文件的create table语句为drop table语句

package com.csii.pweb.query.action;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;


public class JavaFile {
    public static void main(String[] args) {
        try {
            // read file content from file
            StringBuffer sb= new StringBuffer("");

            FileReader reader = new FileReader("D:/t/workflow.sql");
            BufferedReader br = new BufferedReader(reader);

            String str = null;
            final String markStart = "CREATE TABLE";
            List<String> tableNames = new ArrayList<String>();
            while((str = br.readLine()) != null) {
                str = str.toUpperCase().trim(); //转为大写并去除两端空格
                if(str.startsWith(markStart) && !str.startsWith("--")) {    //非注释之建表语句
                    str = str.substring(markStart.length()).replace('(', ' ');    //取表名
                    tableNames.add("DROP TABLE " + str.trim()+";");
//                    System.out.println(str);
                }
            }

            br.close();
            reader.close();
            //倒序
            for(int i=tableNames.size()-1; i>=0;i--) {
                String name = tableNames.get(i);
                sb.append(name).append("\n");
            }
            System.out.println("--------------start---------------");
            System.out.println(sb);
            System.out.println("--------------end---------------"+tableNames.size());

            // write string to file
//            FileWriter writer = new FileWriter("c://test2.txt");
//            BufferedWriter bw = new BufferedWriter(writer);
//            bw.write(sb.toString());
//
//            bw.close();
//            writer.close();
        }
        catch(FileNotFoundException e) {
            e.printStackTrace();
        }
        catch(IOException e) {
            e.printStackTrace();
        }
    }
}