根据javabean转换为mysql建表语句

package com.util;
import java.io.IOException;
import java.lang.reflect.Field;


/**
 * Created by Jeff on 2018/12/5.
 */
public class CreateTableUtil {
    /**
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        createTable(com.entity.SharingFile.class, null);
    }

    public static void createTable(Class obj,String tableName) throws IOException{
        Field[] fields = null;
        fields = obj.getDeclaredFields();
        String param = null;
        String column = null;
        StringBuilder sb = null;
        sb = new StringBuilder(50);
        if(tableName==null||tableName.equals("")){
            //未传表明则默认用类名
            tableName = obj.getName();
            tableName = tableName.substring(tableName.lastIndexOf(".")+1);
        }
        sb.append("drop table if exists ").append(tableName).append(";\r\n");
        sb.append("create table ").append(tableName).append(" ( \r\n");
        boolean firstId = true;
        for(Field f : fields){
            column = f.getName();
            for(int i = 0; i < column.length(); i++)
                if(Character.isUpperCase(column.charAt(i)))
                    column = column.substring(0, i) + ‘_‘ + column.substring(i, i+1).toLowerCase() + column.substring(i+1, column.length());

            sb.append(column).append(" ");
            param = f.getType().getTypeName();
            if(param.equals("java.lang.Integer")){
                sb.append("INTEGER");
            }else{
                sb.append("VARCHAR(20)");//根据需要自行修改
            }
            if(firstId){//类型转换
                sb.append(" PRIMARY KEY AUTO_INCREMENT");
                firstId = false;
            }
            sb.append(",\n");
        }
        String sql = null;
        sql = sb.toString();
        sql = sb.substring(0, sql.length()-2)+"\n)ENGINE = INNODB DEFAULT CHARSET= utf8 AUTO_INCREMENT=1;\r\n";
        System.out.println(sql);
    }

}