import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* 驼峰命名转换
*
* @author 47475
*
*/
public class Tool {
private static Pattern linePattern = Pattern.compile("_(\\w)");
/**
* 下划线转驼峰 ,大写自动转小写<br />
* 例如:USER_NAME->userName<br />
* USERNAME->userName<br />
* USER_NAME->userName<br />
* fParentNoLeader->fParentNoLeader
*
*/
public static String lineToHump(String str) {
/** 正则表达式写法 */
str = str.toLowerCase();
Matcher matcher = linePattern.matcher(str);
StringBuffer sb = new StringBuffer();
while (matcher.find()) {
matcher.appendReplacement(sb, matcher.group(1).toUpperCase());
}
matcher.appendTail(sb);
return sb.toString();
/** 字符串比较写法 */
/*
* if (str == null || "".equals(str.trim())) { return ""; } int len =
* str.length(); StringBuilder sb = new StringBuilder(len); for (int i = 0; i <
* len; i++) { char c = str.charAt(i); if (c == '_') { if (++i < len) {
* sb.append(Character.toUpperCase(str.charAt(i))); } } else { sb.append(c); } }
* return sb.toString();
*/
}
private static Pattern humpPattern = Pattern.compile("[A-Z]");
/**
* 驼峰转下划线,大写自动转小写<br />
* 例如: USER_NAME->user_name USERNAME->userName<br />
* f_parent_no_leader->f_parent_no_leader
*/
public static String humpToLine(String str) {
/** 简单写法,效率不高 */
// return str.replaceAll("[A-Z]", "_$0").toLowerCase();
/** 正则表达式高效写法 */
Matcher matcher = humpPattern.matcher(str);
StringBuffer sb = new StringBuffer();
while (matcher.find()) {
matcher.appendReplacement(sb, "_" + matcher.group(0).toLowerCase());
}
matcher.appendTail(sb);
return sb.toString();
/** 字符串比较写法 */
/*
* if (str == null || "".equals(str.trim())) { return ""; } int len =
* str.length(); StringBuilder sb = new StringBuilder(len); for (int i = 0; i <
* len; i++) { char c = str.charAt(i); if (Character.isUpperCase(c)) {
* sb.append('_'); sb.append(Character.toLowerCase(c)); } else { sb.append(c); }
* } return sb.toString();
*/
}
public static void main(String[] args) {
System.out.println(lineToHump("user_name"));// userName
System.out.println(humpToLine("userName"));// user_name
}
}
Java驼峰命名和下划线命名转换
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转载自blog.csdn.net/Bruce_Up/article/details/84566792
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