实体类反向生成数据库表SQL

package com.xq.tmall.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileOutputStream;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

public class SqlGenerator {
   private static final Logger logger = LoggerFactory.getLogger(SqlGenerator.class);
   
   public static void main(String[] args) {
      //实体类所在的package在磁盘上的绝对路径
      String packageName = "E:/java/resourcesproject/micro/925/Tmall_demo/src/main/java/com/xq/tmall/entity";
      //生成sql的文件夹
      String filePath = "E:/create/";
      //项目中实体类的路径
      String prefix = "com.xq.tmall.entity.";
      String className = "";

      StringBuffer sqls = new StringBuffer();
      //获取包下的所有类名称
      List<String> list = getAllClasses(packageName);
      for (String str : list) {
         className = prefix + str.substring(0, str.lastIndexOf("."));
         String sql = generateSql(className, filePath);
         sqls.append(sql);
      }
      System.out.println(sqls.toString());
      StringToSql(sqls.toString(), filePath + "report.sql");

   }
   /**
    * 根据实体类生成建表语句
    * @author  
    * @date   2018年4月11日
    * @param className 全类名  
    * @param filePath 磁盘路径  如 : d:/workspace/
    */
   public static String generateSql(String className,String filePath){
      try {
         Class<?> clz = Class.forName(className);
         className = clz.getSimpleName();
         Field[] fields = clz.getDeclaredFields();
         StringBuffer column = new StringBuffer();
         String varchar = " varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,";
         for (Field f : fields) {
            column.append(" \n `"+f.getName()+"`").append(varchar);
         }
         StringBuffer sql = new StringBuffer();
         sql.append("\n DROP TABLE IF EXISTS `"+className+"`; ")
            .append(" \n CREATE TABLE `"+className+"`  (")
            .append(" \n `id` int(11) NOT NULL AUTO_INCREMENT,")
            .append(" \n "+column)
            .append(" \n PRIMARY KEY (`id`) USING BTREE,")
            .append("\n INDEX `id`(`id`) USING BTREE")
            .append(" \n ) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8 COLLATE = utf8_general_ci;");
         return sql.toString();
      } catch (ClassNotFoundException e) {
         logger.debug("该类未找到！");
         return null;
      }
      
   }
   
   /**
    * 获取包下的所有类名称,获取的结果类似于 XXX.java
    * @author  
    * @date   2018年4月11日
    * @param packageName
    * @return
    */
   public static List<String> getAllClasses(String packageName){
      List<String> classList = new ArrayList<String>();
      String className="";
      File f = new File(packageName);
      if(f.exists() && f.isDirectory()){
         File[] files = f.listFiles();
         for (File file : files) {
             className = file.getName();
             classList.add(className);
         }
         return classList;
      }else{
         logger.debug("包路径未找到！");
         return null;
      }
   }
   /**
    * 将string 写入sql文件
    * @author  
    * @date   2018年4月11日
    * @param str
    * @param path
    */
   public static void StringToSql(String str,String path){
      byte[] sourceByte = str.getBytes();  
      if(null != sourceByte){  
          try {  
              File file = new File(path);     //文件路径（路径+文件名）  
              if (!file.exists()) {   //文件不存在则创建文件，先创建目录  
                  File dir = new File(file.getParent());  
                  dir.mkdirs();  
                  file.createNewFile();  
              }  
              FileOutputStream outStream = new FileOutputStream(file);    //文件输出流用于将数据写入文件
              outStream.write(sourceByte);  
              outStream.flush();
              outStream.close();  //关闭文件输出流  
              System.out.println("生成成功");
          } catch (Exception e) {  
             e.printStackTrace();
          }  
      }  
   }
}