Java通过实体类生成建表的sql语句-二

比眉伴天荒 2023-10-09 23:13 177阅读 0赞

方式一：

  1. package com.xz;
  3. import com.xz.entity.IndexProduct;//本地实体类
  4. import com.xz.entity.User;//本地实体类
  6. import java.io.BufferedWriter;
  7. import java.io.File;
  8. import java.io.FileOutputStream;
  9. import java.io.IOException;
  10. import java.io.OutputStreamWriter;
  11. import java.lang.annotation.Annotation;
  12. import java.lang.reflect.Field;
  13. import javax.xml.bind.annotation.XmlElement;
  15. public class CreateTable {
  16.     /**
  17.      * @param args
  18.      * @throws IOException
  19.      */
  20.     public static void main(String[] args) throws IOException {
  21.         createTable(User.class, null);
  22. //      createTable(Book.class, null);
  23.     }
  24.     public static void createTable(Class obj,String tableName) throws IOException{
  26.         Field[] fields = null;
  27.         fields = obj.getDeclaredFields();
  28.         Class annotationType = null;
  29.         Object param = null;
  30.         String column = null;
  31.         XmlElement xmlElement = null;
  32.         StringBuilder sb = null;
  33.         sb = new StringBuilder(50);
  34.         if(tableName==null||tableName.equals("")){
  35.         //未传表明默认用类名
  36.             tableName = obj.getName();
  37.             tableName = tableName.substring(tableName.lastIndexOf(".")+1);
  38.         }
  39.         sb.append("\r\ndrop table if exists  ").append(tableName).append(";\r\n");
  40.         sb.append("create table ").append(tableName).append(" ( \r\n");
  41.         System.out.println(tableName);
  42.         boolean firstId = true;
  43.         File file = null;
  44.         for(Field f:fields){
  45.             column = f.getName();
  46.             sb.append(column).append(" ");
  47.             System.out.println(column+","+f.getType());
  48.             param = f.getType();
  49.             sb.append(column);//一般第一个是主键
  50.             if(param instanceof Integer){
  51.                 sb.append(" INTEGER ");
  52.             }else{
  53.                 sb.append(" VARCHAR(30) ");//根据需要自行修改
  54.             }
  55.             if(firstId){//类型转换
  56.                 sb.append(" PRIMARY KEY ");
  57.                 firstId = false;
  58.             }
  59.             //获取字段中包含fieldMeta的注解
  60.             //2、获取属性上的所有注释
  61.             Annotation[] allAnnotations = f.getAnnotations();
  62.             for(Annotation an : allAnnotations){
  63.                 sb.append(" COMMIT '");
  64.                 xmlElement = (XmlElement)an;
  65.                 annotationType = an.annotationType();
  66.                 param = ((XmlElement) an).name();
  67.                 System.out.println("属性【"+f.getName()+"-----的注释类型有: " + param);
  68.                 sb.append(param).append("'");
  69.             }
  70.             sb.append(",\n ");
  71.         }
  72.         String sql = null;
  73.         sql = sb.toString();
  74.         sql = sb.substring(0, sql.length()-1)+" )ENGINE =INNODB DEFAULT  CHARSET= utf8;\r\n";
  75.         file = new File("WebContent/createTable/User.sql");  //文件保存路径与命名
  76.         if (!file.getParentFile().exists()) {
  77.             if (!file.getParentFile().mkdirs()) {
  78.             }
  79.         }
  80.         if (!file.exists()) {
  81.             file.createNewFile();
  82.         }
  83.         System.out.println("文件路径:"+file.getAbsolutePath());
  84.         BufferedWriter out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file,true)));
  85.         out.write(sql) ;
  86.         out.flush();
  87.         out.close() ;
  88.     }
  89. }

实体类:

  1. package com.xz.entity;
  3. import lombok.AllArgsConstructor;
  4. import lombok.Data;
  5. import lombok.NoArgsConstructor;
  7. @Data
  8. //使用这个注解，就不用再去手写Getter,Setter,equals,canEqual,hasCode,toString等方法了，注解后在编译时会自动加进去。
  9. @AllArgsConstructor
  10. //使用后添加一个构造函数，该构造函数含有所有已声明字段属性参数
  11. @NoArgsConstructor
  12. //使用后创建一个无参构造函数
  13. public class User {
  14.     private int uid;
  15.     private String uname;
  16.     private String upwd;
  17.     private String email;
  18.     private String phone;
  19.     private String avatar;
  20.     private String user_name;
  21.     private int gender;
  22. }

成功演示:

在这里插入图片描述

方式二：

  1. package com.xz;
  3. import org.slf4j.Logger;
  4. import org.slf4j.LoggerFactory;
  6. import java.io.File;
  7. import java.io.FileOutputStream;
  8. import java.io.IOException;
  9. import java.lang.reflect.Field;
  10. import java.util.ArrayList;
  11. import java.util.HashMap;
  12. import java.util.List;
  13. import java.util.Map;
  15. public class SqlGenerator {
  17.     private static final Logger logger = LoggerFactory.getLogger(SqlGenerator.class);
  19.     /**
  20.      * 用来存储Java等属性类型与sql中属性类型的对照
  21.      * </br>
  22.      * 例如：java.lang.Integer 对应 integer
  23.      */
  24.     public static Map<String, String> map = new HashMap<>();
  26.     public static void main(String[] args) {
  28.         map.put("class java.lang.String", "varchar(255)");
  29.         map.put("class java.lang.Integer", "int");
  30.         map.put("class java.lang.Long", "integer unsigned");
  31.         map.put("class java.lang.byte[]", "blob");
  32.         map.put("class java.lang.Boolean", "bit");
  33.         map.put("class java.math.BigInteger", "bigint unsigned");
  34.         map.put("class java.lang.Float", "float");
  35.         map.put("class java.lang.Double", "double");
  36.         map.put("class java.sql.Date", "datetime");
  37.         map.put("class java.sql.Time", "time");
  38.         map.put("class java.sql.Timestamp", "datetime");
  39.         map.put("class java.util.Date", "datetime");
  40.         map.put("class java.time.LocalDateTime", "datetime");
  41.         map.put("class java.time.LocalDate", "date");
  42.         map.put("class java.time.LocalTime", "time");
  43.         map.put("class java.lang.Byte", "tinyint");
  44.         map.put("class java.math.BigDecimal", "decimal");
  46.         //实体类所在的package在磁盘上的绝对路径
  47.         String packageName = "D:/pro/m_system/src/main/java/com/test/model/entity";
  48.         //生成的sql文件名
  49.         String sqlName = "entityToSql";
  50.         //生成sql的文件夹
  51.         String filePath = "D:/pscp/" + sqlName;
  52.         //表命名前缀
  53.         String tablePrefix = "is_";
  54.         //项目中实体类的路径,（可以不用修改）
  55. //        String prefix = "com.test.model.entity.";
  56.         String prefix = packageName.substring(packageName.indexOf("java") + 5).replace("/", ".") + ".";
  57.         //开始构造sql
  58.         sqlConstruction(packageName, filePath, prefix, tablePrefix);
  59.     }
  61.     /**
  62.      * 生成sql建库语句
  63.      * @param tablePrefix 表命名前缀
  64.      * @param packageName 实体类所在的package在磁盘上的绝对路径
  65.      * @param filePath 生成sql的文件夹
  66.      * @param prefix 项目中实体类的路径
  67.      */
  68.     private static void sqlConstruction(String packageName, String filePath, String prefix, String tablePrefix) {
  70.         String className = "";
  72.         StringBuffer sqls = new StringBuffer();
  73.         //获取包下的所有类名称
  74.         List<String> list = getAllClasses(packageName);
  75.         for (String str : list) {
  76.             className = prefix + str.substring(0, str.lastIndexOf("."));
  77.             String sql = generateSql(className, tablePrefix);
  78.             sqls.append(sql);
  79.         }
  80.         StringToSql(sqls.toString(), filePath + ".sql");
  81.     }
  83.     /**
  84.      * 根据实体类生成建表语句
  85.      *
  86.      * @param className 全类名
  87.      * @param tablePrefix  表命名前缀
  88.      * @return
  89.      */
  90.     public static String generateSql(String className, String tablePrefix) {
  91.         try {
  92.             Class<?> clz = Class.forName(className);
  93.             className = clz.getSimpleName();
  94.             // 表表名adminUser → tb_admin_user
  95.             className = tablePrefix + getStandardFields(className);
  96.             Field[] fields = clz.getDeclaredFields();
  97.             StringBuffer column = new StringBuffer();
  98.             String varchar = " CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,";
  99.             for (Field f : fields) {
  100.                 if ("class java.lang.String".equals(f.getType().toString())){
  101.                     column.append(" \n `" + getStandardFields(f.getName()) + "`" + " " + map.get(f.getType().toString())).append(varchar);
  102.                 }else {
  103.                     column.append(" \n `" + getStandardFields(f.getName()) + "`" + " " + map.get(f.getType().toString())).append(",");
  104.                 }
  105.             }
  106.             //已单独指定id列的生成语句，去掉多余id的拼接
  107.             String column1 = column.substring(column.indexOf(",") + 1);
  108.             StringBuffer sql = new StringBuffer();
  109.             sql.append("\n -- 表 " + className + "\n")
  110.                     .append("\n DROP TABLE IF EXISTS `" + className + "`; ")
  111.                     .append(" \n CREATE TABLE `" + className + "`  (")
  112.                     .append(" \n `id` int(11) NOT NULL AUTO_INCREMENT,")
  113.                     .append(" " + column1)
  114.                     .append(" \n PRIMARY KEY (`id`) USING BTREE,")
  115.                     .append("\n INDEX `id`(`id`) USING BTREE")
  116.                     .append(" \n ) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8 COLLATE = utf8_general_ci; \n");
  117.             return sql.toString();
  118.         } catch (ClassNotFoundException e) {
  119.             logger.debug("该类未找到！");
  120.             return null;
  121.         }
  123.     }
  125.     /**
  126.      * 转换为标准等sql字段 例如 adminUser → admin_user
  127.      *
  128.      * @param str 转换为字符串的字段名
  129.      * @return
  130.      */
  131.     public static String getStandardFields(String str) {
  132.         StringBuffer sb = new StringBuffer();
  133.         for (int i = 0; i < str.length(); i++) {
  134.             char c = str.charAt(i);
  135.             //非首字母，在大写字母A到Z之间
  136.             if (i != 0 && (c >= 'A' && c <= 'Z')) {
  137.                 sb.append("_");
  138.             }
  139.             sb.append(c);
  140.         }
  141.         return sb.toString();
  142.     }
  144.     /**
  145.      * 获取包下面等所有实体类名称，类似于获取 XXX.java
  146.      *
  147.      * @param packageName 全类名
  148.      * @return
  149.      */
  150.     public static List<String> getAllClasses(String packageName) {
  151.         List<String> classList = new ArrayList();
  152.         String className = "";
  153.         File f = new File(packageName);
  154.         if (f.exists() && f.isDirectory()) {
  155.             File[] files = f.listFiles();
  156.             // 遍历实体类下面等所有.java文件 获取其类名
  157.             for (File file : files) {
  158.                 className = file.getName();
  159.                 classList.add(className);
  160.             }
  161.             return classList;
  162.         } else {
  163.             logger.debug("包路径未找到！");
  164.             return null;
  165.         }
  166.     }
  168.     /**
  169.      * 将生成等String字符串 写进sql文件
  170.      *
  171.      * @param str  String字符串
  172.      * @param path sql文件路径路径
  173.      */
  174.     public static void StringToSql(String str, String path) {
  175.         byte[] sourceByte = str.getBytes();
  176.         FileOutputStream os = null;
  177.         if (null != sourceByte) {
  178.             try {
  179.                 //文件路径（路径+文件名）
  180.                 File file = new File(path);
  181.                 //文件不存在则创建文件，先创建目录
  182.                 if (!file.exists()) {
  183.                     File dir = new File(file.getParent());
  184.                     dir.mkdirs();
  185.                     file.createNewFile();
  186.                 }
  187.                 //文件输出流用于将数据写入文件
  188.                 os = new FileOutputStream(file);
  189.                 os.write(sourceByte);
  190.                 os.flush();
  191.                 System.out.println("生成成功!!");
  192.             } catch (Exception e) {
  193.                 e.printStackTrace();
  194.             } finally {
  195.                 // 关闭文件输出流
  196.                 try {
  197.                     if (os != null) {
  198.                         os.close();
  199.                     }
  200.                 } catch (IOException e) {
  201.                     e.printStackTrace();
  202.                 }
  203.             }
  204.         }
  205.     }
  206. }

发表评论

表情：
评论列表 （有 0 条评论，177人围观）

还没有评论，来说两句吧...

相关阅读