import java.lang.reflect.Field;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

/***

*

* @author Brandon Leaf

* @date 2021/1/20 16:01

* @description

* 生成器

*/

public class Gener {

private final Map, String> typeMap = new HashMap<>();

/**

* 初始化类型映射表

*/

private void initDefaultTypeMap() {

typeMap.put(String.class, "VARCHAR2(100 BYTE)");

typeMap.put(Long.class, "NUMBER");

typeMap.put(Double.class, "NUMBER(*,6)");

typeMap.put(Integer.class, "NUMBER");

}

public Gener() {

if (typeMap.isEmpty()) {

initDefaultTypeMap();

}

}

/**

*

* @param customTypeMap 自定义映射表

*/

public Gener(Map, String> customTypeMap) {

typeMap.putAll(customTypeMap);

}

/**

*

* @param classList 类列表

* @param tablePrefix 表前缀

* @return create sql

*/

public String genCreateSql(List> classList, String tablePrefix) {

StringBuilder sb = new StringBuilder("-- =====entity to create sql=====\n");

for (Class> c : classList) {

Field[] declaredFields = c.getDeclaredFields();

List fieldList = new ArrayList<>();

for(Field f : declaredFields){

String type = typeMap.get(f.getType());

if(type!=null){

fieldList.add(f);

}

}

if(fieldList.isEmpty()){

continue;

}

//title

String tableName = c.getSimpleName();

String sqlTableName = enCodeUnderlined(tableName);

if (tablePrefix != null) {

sqlTableName = tablePrefix.toUpperCase() + sqlTableName.toUpperCase();

}

sb.append("-- =====").append(tableName).append("=====").append(sqlTableName).append("=====\n\n\t");

sb.append("CREATE TABLE \"").append(sqlTableName).append("\" (\n\t");

//todo columns

for (int i = 0; i < fieldList.size(); i++) {

Field f = fieldList.get(i);

String type = typeMap.get(f.getType());

String name = f.getName();

sb.append("\"").append(enCodeUnderlined(name).toUpperCase()).append("\" ").append(type);

if (i != (fieldList.size() - 1)) {

sb.append(" ,\n\t");

}

}

sb.append("\n\t);\n\n");

//todo remark

}

return sb.toString();

}

// 首字母转小写

public static String toLowerCaseFirstOne(String s) {

if (Character.isLowerCase(s.charAt(0)))

return s;

else

return Character.toLowerCase(s.charAt(0)) +

s.substring(1);

}

// 大写字母前面加上下划线并转为全小写

public static String enCodeUnderlined(String s) {

char[] chars = toLowerCaseFirstOne(s).toCharArray();

StringBuilder temp = new StringBuilder();

for (char aChar : chars) {

if (Character.isUpperCase(aChar)) {

temp.append("_");

}

temp.append(Character.toLowerCase(aChar));

}

return temp.toString();

}

/**

* demo

*/

public static void main(String[] args) {

Gener gener = new Gener();

String s = gener.genCreateSql(

List.of(Test1.class,

Test2.class,

Test3.class

)

, "TEST_");

//打印sql

System.out.println(s);

}

}