mysql 自动生产java 实体类脚本

ゝ一纸荒年。 2022-04-15 06:11 168阅读 0赞

mysql有表了，但是要建实体类，都是重复性工作，比较浪费时间，于是有了自动生成实体类的想法。如果用mybatis generator，会生成很多没必要的代码，而且很多，看起来更乱了，实际执行的sql，比普通的增删查改要复杂，生成的sql也其实没什么用，实体类还比较有用，于是只要生成实体类。  
本文参考改写自：[https://blog.csdn.net/zhum\_sjz/article/details/80343549][https_blog.csdn.net_zhum_sjz_article_details_80343549] 非常感谢。加上了下划线转驼峰和lombok。  
本文用的是lombok，如果不用lombok，稍微修改下代码即可。如果需要加入什么包，设置就可以了。

package com.pydt.fgw.core;
    import java.io.File;
    import java.io.FileWriter;
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSetMetaData;
    import java.sql.SQLException;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    
    /**
     * 从数据库表反射出实体类，自动生成实体类
     *
     * @author fangshetian
     *
     */
    public class SqlHelper {
        //基本数据配置
        private String packageOutPath = "com.pydt.fgw.core.model";// 指定实体生成所在包的路径
        private String authorName = "fangsht";// 作者名字
        private String tablename = "xxx";// 表名
        private String[] colnames; // 列名数组
        private String[] colTypes; // 列名类型数组
        private String version = "V0.01"; // 版本
        private int[] colSizes; // 列名大小数组
        private boolean f_util = false; // 是否需要导入包java.util.*
        private boolean f_sql = false; // 是否需要导入包java.sql.*
        private boolean f_lang = false; // 是否需要导入包java.sql.*
        private String defaultPath = "/src/main/java/";
        // 数据库连接
        private static final String URL = "jdbc:mysql://192.168.1.xxx:3306/xxx";
        private static final String NAME = "user";
        private static final String PASS = "passwd";
        private static final String DRIVER = "com.mysql.jdbc.Driver";
    
        /*
         * 构造函数
         */
        public SqlHelper() {
            // 创建连接
            Connection con;
            // 查要生成实体类的表
            String sql = "select * from " + tablename;
            PreparedStatement pStemt = null;
            try {
                try {
                    Class.forName(DRIVER);
                } catch (ClassNotFoundException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
                con = DriverManager.getConnection(URL, NAME, PASS);
                pStemt = con.prepareStatement(sql);
                ResultSetMetaData rsmd = pStemt.getMetaData();
                int size = rsmd.getColumnCount(); // 统计列
                colnames = new String[size];
                colTypes = new String[size];
                colSizes = new int[size];
                for (int i = 0; i < size; i++) {
    
                    colnames[i] = rsmd.getColumnName(i + 1);
                    colTypes[i] = rsmd.getColumnTypeName(i + 1);
                    //自动生成包配置
    
    
                    // if (colTypes[i].equalsIgnoreCase("datetime")) {
                    // f_util = true;
                    // }
                    if (colTypes[i].equalsIgnoreCase("image") || colTypes[i].equalsIgnoreCase("text")
                            || colTypes[i].equalsIgnoreCase("datetime") || colTypes[i].equalsIgnoreCase("time")
                            || colTypes[i].equalsIgnoreCase("date") || colTypes[i].equalsIgnoreCase("datetime2")) {
                        f_sql = true;
                    }
                    // if (colTypes[i].equalsIgnoreCase("int")) {
                    // f_lang = true;
                    // }
                    colSizes[i] = rsmd.getColumnDisplaySize(i + 1);
                }
    
                String content = parse(colnames, colTypes, colSizes);
    
                try {
                    File directory = new File("");
    
                    String path = this.getClass().getResource("").getPath();
    
                    System.out.println(path);
    
                    String outputPath = directory.getAbsolutePath() + this.defaultPath
                            + this.packageOutPath.replace(".", "/") + "/" + initcap(underlineToHump(tablename)) + ".java";
                    System.out.println("执行完毕，生成路径为："+outputPath);
                    FileWriter fw = new FileWriter(outputPath);
                    PrintWriter pw = new PrintWriter(fw);
                    pw.println(content);
                    pw.flush();
                    pw.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
    
            } catch (SQLException e) {
                e.printStackTrace();
            } finally {
    
            }
        }
    
        /**
         * 功能：生成实体类主体代码
         *
         * @param colnames
         * @param colTypes
         * @param colSizes
         * @return
         */
        private String parse(String[] colnames, String[] colTypes, int[] colSizes) {
            StringBuffer sb = new StringBuffer();
            // 生成package包路径
            sb.append("package " + this.packageOutPath + ";\r\n");
            // 判断是否导入工具包
            if (f_util) {
                sb.append("import java.util.Date;\r\n");
            }
            if (f_sql) {
                sb.append("import java.sql.*;\r\n");
            }
            if (f_lang) {
                sb.append("import java.lang.*;\r\n");
            }
            sb.append("import lombok.Data;\r\n");
    
            sb.append("\r\n");
            // 注释部分
            sb.append("   /**\r\n");
            sb.append("    * @文件名称：" + initcap(underlineToHump(this.tablename)) + ".java\r\n");
            sb.append("    * @创建时间：" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + "\r\n");
            sb.append("    * @创  建  人：" + this.authorName + " \r\n");
            sb.append("    * @文件描述：" + tablename + " 实体类\r\n");
            sb.append("    * @文件版本：" + this.version + " \r\n");
            sb.append("    */ \r\n");
            sb.append("\n\r\n@Data");
            // 实体部分
            sb.append("\npublic class " + initcap(underlineToHump(tablename)) + "{\r\n");
            processAllAttrs(sb);// 属性
    //        processAllMethod(sb);// get set方法
            sb.append("}\r\n");
    
            // System.out.println(sb.toString());
            return sb.toString();
        }
    
        /**
         * 功能：生成所有属性
         *
         * @param sb
         */
        private void processAllAttrs(StringBuffer sb) {
    
            for (int i = 0; i < colnames.length; i++) {
                sb.append("\tprivate " + sqlType2JavaType(colTypes[i]) + " " + this.underlineToHump(colnames[i]) + ";\r\n");
            }
    
        }
    
        /**
         * 功能：生成所有方法
         *
         * @param sb
         */
    //    private void processAllMethod(StringBuffer sb) {
    //
    //        for (int i = 0; i < colnames.length; i++) {
    //            sb.append("\tpublic void set" + initcap(colnames[i]) + "(" + sqlType2JavaType(colTypes[i]) + " "
    //                    + colnames[i] + "){\r\n");
    //            sb.append("\tthis." + colnames[i] + "=" + colnames[i] + ";\r\n");
    //            sb.append("\t}\r\n");
    //            sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get" + initcap(colnames[i]) + "(){\r\n");
    //            sb.append("\t\treturn " + colnames[i] + ";\r\n");
    //            sb.append("\t}\r\n");
    //        }
    //
    //    }
    
        /**
         * 功能：将输入字符串的首字母改成大写
         *
         * @param str
         * @return
         */
        private String initcap(String str) {
    
            char[] ch = str.toCharArray();
            if (ch[0] >= 'a' && ch[0] <= 'z') {
                ch[0] = (char) (ch[0] - 32);
            }
    
            return new String(ch);
        }
    
        /**
         * 功能：获得列的数据类型
         *
         * @param sqlType
         * @return
         */
        private String sqlType2JavaType(String sqlType) {
    
            if (sqlType.equalsIgnoreCase("bit")) {
                return "Boolean";
            } else if (sqlType.equalsIgnoreCase("decimal") || sqlType.equalsIgnoreCase("money")
                    || sqlType.equalsIgnoreCase("smallmoney") || sqlType.equalsIgnoreCase("numeric")
                    || sqlType.equalsIgnoreCase("bigint")) {
                return "Long";
            } else if (sqlType.equalsIgnoreCase("float")) {
                return "Double";
            } else if (sqlType.equalsIgnoreCase("int") || sqlType.equalsIgnoreCase("int identity")) {
                return "Integer";
            } else if (sqlType.equalsIgnoreCase("image") || sqlType.equalsIgnoreCase("varbinary(max)")
                    || sqlType.equalsIgnoreCase("varbinary") || sqlType.equalsIgnoreCase("udt")
                    || sqlType.equalsIgnoreCase("binary")) {
                return "Byte[]";
            } else if (sqlType.equalsIgnoreCase("nchar") || sqlType.equalsIgnoreCase("nvarchar(max)")
                    || sqlType.equalsIgnoreCase("nvarchar") || sqlType.equalsIgnoreCase("nvarchar(ntext)")
                    || sqlType.equalsIgnoreCase("uniqueidentifier") || sqlType.equalsIgnoreCase("xml")
                    || sqlType.equalsIgnoreCase("char") || sqlType.equalsIgnoreCase("varchar(max)")
                    || sqlType.equalsIgnoreCase("text") || sqlType.equalsIgnoreCase("varchar")) {
                return "String";
            } else if (sqlType.equalsIgnoreCase("real")) {
                return "Float";
            } else if (sqlType.equalsIgnoreCase("smallint") || sqlType.equalsIgnoreCase("tinyint")) {
                return "Short";
            } else if (sqlType.equalsIgnoreCase("date") || sqlType.equalsIgnoreCase("datetime")
                    || sqlType.equalsIgnoreCase("time") || sqlType.equalsIgnoreCase("datetime2")
                    || sqlType.equalsIgnoreCase("timestamp") )  {
                return "Date";
            } else {
                System.out.println("数据类型异常，类型为：" + sqlType);
            }
    
            return null;
        }
            /**
         * 下划线转驼峰
         *
         * @String para
         */
        private  String underlineToHump(String para){
            StringBuilder result=new StringBuilder();
            String a[]=para.split("_");
            for(String s:a){
                if(result.length()==0){
                    result.append(s.toLowerCase());
                }else{
                    result.append(s.substring(0, 1).toUpperCase());
                    result.append(s.substring(1).toLowerCase());
                }
            }
            return result.toString();
        }
    
    
        /**
         * 出口 TODO
         *
         * @param args
         */
        public static void main(String[] args) {
    
            new SqlHelper();
    
        }
    }

[https_blog.csdn.net_zhum_sjz_article_details_80343549]: https://blog.csdn.net/zhum_sjz/article/details/80343549