me.wuwenbin.modules.sql.util.SQLDefineUtils Maven / Gradle / Ivy
package me.wuwenbin.modules.sql.util;
import java.util.regex.Matcher;
import static java.util.regex.Pattern.compile;
/**
* some utils of sql building
*
*
* @author wuwenbin
* @date 2017/1/9
*/
public class SQLDefineUtils {
/**
* 驼峰命名转下划线
*
* @param param to transfer
* @return {@link String}
*/
private static String camelToUnderline(String param) {
if (param != null && !"".equals(param.trim())) {
int len = param.length();
StringBuilder sb = new StringBuilder(len);
for (int i = 0; i < len; i++) {
char c = param.charAt(i);
if (!Character.isUpperCase(c)) {
sb.append(c);
} else {
sb.append('_').append(Character.toLowerCase(c));
}
}
return sb.toString();
} else {
return "";
}
}
/**
* 下划线转驼峰命名
*
* @param param to transfer
* @return {@link String}
*/
public static String underline2Camel(String param) {
if (param == null || "".equals(param.trim())) {
return "";
} else {
StringBuilder sb = new StringBuilder(param);
Matcher mc = compile("_").matcher(param);
int i = 0;
while (mc.find()) {
int position = mc.end() - (i++);
sb.replace(position - 1, position + 1, sb.substring(position, position + 1).toUpperCase());
}
return sb.toString();
}
}
/**
* 如果用户指定了column的列名就按用户指定的来，没有则驼峰命名转化为下划线命名
*
* @param charName the charName of db
* @param fieldName the custom name of charName
* @return {@link String}
*/
public static String java2SQL(String charName, String fieldName) {
if (charName == null || "".equals(charName)) {
String newName = camelToUnderline(fieldName);
if (!"_".equals(newName.substring(0, 1))) {
return newName;
} else {
return newName.substring(1, newName.length());
}
} else {
return charName;
}
}
}