java中驼峰与下划线的写法互转

package day0704;import java.util.regex.Matcher;import java.util.regex.Pattern;/** * 驼峰法-下划线互转 * @author cshaper * @since 2015.07.04 * @version 1.0.0 */public class Underline2Camel {  /**  * 下划线转驼峰法  * @param line 源字符串  * @param smallCamel 大小驼峰,是否为小驼峰  * @return 转换后的字符串  */ public static String underline2Camel(String line,boolean smallCamel){  if(line==null||"".equals(line)){   return "";  }  StringBuffer sb=new StringBuffer();  Pattern pattern=Pattern.compile("([A-Za-z//d]+)(_)?");  Matcher matcher=pattern.matcher(line);  while(matcher.find()){   String word=matcher.group();   sb.append(smallCamel&&matcher.start()==0?Character.toLowerCase(word.charAt(0)):Character.toUpperCase(word.charAt(0)));   int index=word.lastIndexOf('_');   if(index>0){    sb.append(word.substring(1, index).toLowerCase());   }else{    sb.append(word.substring(1).toLowerCase());   }  }  return sb.toString(); } /**  * 驼峰法转下划线  * @param line 源字符串  * @return 转换后的字符串  */ public static String camel2Underline(String line){  if(line==null||"".equals(line)){   return "";  }  line=String.valueOf(line.charAt(0)).toUpperCase().concat(line.substring(1));  StringBuffer sb=new StringBuffer();  Pattern pattern=Pattern.compile("[A-Z]([a-z//d]+)?");  Matcher matcher=pattern.matcher(line);  while(matcher.find()){   String word=matcher.group();   sb.append(word.toUpperCase());   sb.append(matcher.end()==line.length()?"":"_");  }  return sb.toString(); } public static void main(String[] args) {  String line="I_HAVE_AN_IPANG3_PIG";  String camel=underline2Camel(line,true);  System.out.println(camel);  System.out.println(camel2Underline(camel)); }}