一键生成实体类建表SQL

一时失言乱红尘 2022-10-09 14:26 186阅读 0赞

package com.zyq.util;
    
    import java.lang.reflect.Field;
    import java.util.Date;
    import java.util.LinkedHashMap;
    import java.util.Map;
    import java.util.Objects;
    
    import com.zyq.entity.Command;
    import io.swagger.annotations.ApiModel;
    import io.swagger.annotations.ApiModelProperty;
    
    /**
     * 这是一个自动生成 SQL 语句的类，只需要修改变量 CLS 的参数为对应类（如User.class）<br>
     * 然后执行main方法，就可以得到该类的建表SQL语句，以及对应的插入模拟SQL。
     * 
     * @author ZhangYuanqiang
     * @since 2021年4月13日
     */
    public class CreateTableSqlUtil {
    
        private static final Class<?> CLS = Command.class;
        private static final String LINE = "\r\n";
        private static Map<String, String> map = new LinkedHashMap<String, String>();
    
        public static void main(String[] args) throws Exception {
            // 获取建表 SQL
            createSQL();
            // 获取（参数条）测试数据 SQL
            createInsertData(2);
        }
    
        /**
         * 获取建表SQL（执行后控制台会自动输出建表语句SQL）
         * 
         * @throws Exception
         */
        private static void createSQL() throws Exception {
            StringBuilder sb = new StringBuilder();
            sb.append("CREATE TABLE `").append(getSqlAttrName(CLS.getSimpleName())).append("` (").append(LINE);
            sb.append("  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键ID',").append(LINE);
            sb.append("  `create_time` datetime DEFAULT NULL COMMENT '创建时间',").append(LINE);
            sb.append("  `update_time` datetime DEFAULT NULL COMMENT '创建时间',").append(LINE);
            sb.append("  `deleted` smallint DEFAULT 0 COMMENT '是否已删除：0-未删除，1-已删除',").append(LINE);
            sb.append("  `version` smallint DEFAULT 0 COMMENT '版本号',").append(LINE);
            // 获取其他参数
            Field[] fields = CLS.getDeclaredFields();
            for (Field field : fields) {
                String type = field.getType().getSimpleName();
                String key = getSqlAttrName(field.getName());
                String comment = getComment(field, false);
                switch (type) {
                case "String":
                    sb.append("  `").append(key).append("` varchar(255) DEFAULT NULL COMMENT ").append(comment).append(",")
                            .append(LINE);
                    break;
                case "int":
                case "Integer":
                    comment = getComment(field, true);
                    if (isStatusAndType(field.getName())) {
                        sb.append("  `").append(key).append("` smallint(2) DEFAULT 0 COMMENT ").append(comment).append(",")
                                .append(LINE);
                    } else {
                        sb.append("  `").append(key).append("` int(11) DEFAULT 0 COMMENT ").append(comment).append(",")
                                .append(LINE);
                    }
                    break;
                case "long":
                case "Long":
                    comment = getComment(field, true);
                    sb.append("  `").append(key).append("` bigint(20) DEFAULT 0 COMMENT ").append(comment).append(",")
                            .append(LINE);
                    break;
                case "Date":
                    sb.append("  `").append(key).append("` datetime DEFAULT NULL COMMENT ").append(comment).append(",")
                            .append(LINE);
                    break;
                default:
                    throw new Exception("未知属性类型：" + type);
                }
            }
            sb.append("  PRIMARY KEY (`id`)").append(LINE);
            sb.append(") ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COMMENT'").append(getApiModelName())
                    .append("表';").append(LINE);
            System.out.println("-- 创建表SQL");
            System.out.println(sb.toString());
        }
    
        /**
         * 创建测试数据 SQL（控制台会自动打印SQL）
         * 
         * @param size_需要生成多少条测试数据
         */
        private static void createInsertData(int size) {
            if (size <= 0) {
                return;
            }
            System.out.println("-- 测试数据 " + size + " 条");
            long id = 1;
            String date = "'" + DateUtil.formatDateTime(new Date()) + "'";
            for (int i = 0; i < size; i++) {
                String attrs = "";
                String params = "";
                for (String attr : map.keySet()) {
                    attrs += ", " + attr;
                    params += ", " + map.get(attr);
                }
                String sql = String.format(
                        "INSERT INTO " + getSqlAttrName(CLS.getSimpleName())
                                + " (id, create_time, update_time %s) VALUES (%s, %s, %s %s);",
                        attrs, id, date, date, params);
                id++;
                System.out.println(sql);
            }
        }
    
        private static String getSqlAttrName(String attr) {
            char[] array = attr.toCharArray();
            StringBuilder sb = new StringBuilder();
            int idx = 0;
            for (char c : array) {
                if (c >= 'a' && c <= 'z') {
                    sb.append(c);
                } else {
                    if (idx > 0) {
                        sb.append("_");
                    }
                    sb.append(String.valueOf(c).toLowerCase());
                }
                idx++;
            }
            return sb.toString();
        }
    
        private static String getApiModelName() {
            ApiModel model = CLS.getAnnotation(ApiModel.class);
            if (Objects.isNull(model)) {
                return "";
            }
            return BaseUtil.getString(model.value());
        }
    
        private static String getComment(Field field, boolean isNumber) {
            String sqlFiledName = getSqlAttrName(field.getName());
            ApiModelProperty property = field.getAnnotation(ApiModelProperty.class);
            if (Objects.isNull(property)) {
                if (isNumber) {
                    map.put(sqlFiledName, "0");
                } else {
                    map.put(sqlFiledName, "NULL");
                }
                return "''";
            }
            // 是否有默认值
            String expmale = BaseUtil.getString(property.example());
            if (isNumber) {
                map.put(sqlFiledName, expmale);
            } else {
                map.put(sqlFiledName, "'" + expmale + "'");
            }
            return "'" + BaseUtil.getString(property.value()) + "'";
        }
    
        private static boolean isStatusAndType(String s) {
            s = s.toLowerCase();
            return s.endsWith("status") || s.endsWith("type");
        }
    
    }