Java通过实体类生成sql语句
package com.xz;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class SqlGenerator {
private static final Logger logger = LoggerFactory.getLogger(SqlGenerator.class);
/**
* 用来存储Java等属性类型与sql中属性类型的对照
* </br>
* 例如： 对应 integer
*/
public static Map<String, String> map = new HashMap<>();
public static void main(String[] args) {
map.put("class ", "varchar(255)");
map.put("class ", "int");
map.put("class ", "integer unsigned");
map.put("class []", "blob");
map.put("class ", "bit");
map.put("class ", "bigint unsigned");
map.put("class ", "float");
map.put("class ", "double");
map.put("class ", "datetime");
map.put("class ", "time");
map.put("class ", "datetime");
map.put("class ", "datetime");
map.put("class ", "datetime");
map.put("class ", "date");
map.put("class ", "time");
map.put("class ", "tinyint");
map.put("class ", "decimal");
//实体类所在的package在磁盘上的绝对路径
String packageName = "D:/pro/m_system/src/main/java/com/test/model/entity";
//生成的sql文件名
String sqlName = "entityToSql";
//生成sql的文件夹
String filePath = "D:/pscp/" + sqlName;
//表命名前缀
String tablePrefix = "is_";
//项目中实体类的路径,（可以不用修改）
// String prefix = ".";
String prefix = packageName.substring(packageName.indexOf("java") + 5).replace("/", ".") + ".";
//开始构造sql
sqlConstruction(packageName, filePath, prefix, tablePrefix);
}
/**
* 生成sql建库语句
* @param tablePrefix 表命名前缀
* @param packageName 实体类所在的package在磁盘上的绝对路径
* @param filePath 生成sql的文件夹
* @param prefix 项目中实体类的路径
*/
private static void sqlConstruction(String packageName, String filePath, String prefix, String tablePrefix) {
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, tablePrefix);
sqls.append(sql);
}
StringToSql(sqls.toString(), filePath + ".sql");
}
/**
* 根据实体类生成建表语句
*
* @param className 全类名
* @param tablePrefix 表命名前缀
* @return
*/
public static String generateSql(String className, String tablePrefix) {
try {
Class<?> clz = Class.forName(className);
className = clz.getSimpleName();
// 表表名adminUser → tb_admin_user
className = tablePrefix + getStandardFields(className);
Field[] fields = clz.getDeclaredFields();
StringBuffer column = new StringBuffer();
String varchar = " CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,";
for (Field f : fields) {
if ("class ".equals(f.getType().toString())){
column.append(" \n `" + getStandardFields(f.getName()) + "`" + " " + map.get(f.getType().toString())).append(varchar);
}else {
column.append(" \n `" + getStandardFields(f.getName()) + "`" + " " + map.get(f.getType().toString())).append(",");
}
}
//已单独指定id列的生成语句，去掉多余id的拼接
String column1 = column.substring(column.indexOf(",") + 1);
StringBuffer sql = new StringBuffer();
sql.append("\n -- 表 " + className + "\n")
.append("\n DROP TABLE IF EXISTS `" + className + "`; ")
.append(" \n CREATE TABLE `" + className + "` (")
.append(" \n `id` int(11) NOT NULL AUTO_INCREMENT,")
.append(" " + column1)
.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; \n");
return sql.toString();
} catch (ClassNotFoundException e) {
logger.debug("该类未找到！");
return null;
}
}
/**
* 转换为标准等sql字段 例如 adminUser → admin_user
*
* @param str 转换为字符串的字段名
* @return
*/
public static String getStandardFields(String str) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < str.length(); i++) {
char c = str.charAt(i);
//非首字母，在大写字母A到Z之间
if (i != 0 && (c >= 'A' && c <= 'Z')) {
sb.append("_");
}
sb.append(c);
}
return sb.toString();
}
/**
* 获取包下面等所有实体类名称，类似于获取
*
* @param packageName 全类名
* @return
*/
public static List<String> getAllClasses(String packageName) {
List<String> classList = new ArrayList();
String className = "";
File f = new File(packageName);
if (f.exists() && f.isDirectory()) {
File[] files = f.listFiles();
// 遍历实体类下面等所有.java文件 获取其类名
for (File file : files) {
className = file.getName();
classList.add(className);
}
return classList;
} else {
logger.debug("包路径未找到！");
return null;
}
}
/**
* 将生成等String字符串 写进sql文件
*
* @param str String字符串
* @param path sql文件路径路径
*/
public static void StringToSql(String str, String path) {
byte[] sourceByte = str.getBytes();
FileOutputStream os = null;
if (null != sourceByte) {
try {
//文件路径（路径+文件名）
File file = new File(path);
//文件不存在则创建文件，先创建目录
if (!file.exists()) {
File dir = new File(file.getParent());
dir.mkdirs();
file.createNewFile();
}
//文件输出流用于将数据写入文件
os = new FileOutputStream(file);
os.write(sourceByte);
os.flush();
System.out.println("生成成功!!");
} catch (Exception e) {
e.printStackTrace();
} finally {
// 关闭文件输出流
try {
if (os != null) {
os.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}