java中驼峰与下划线写法互转的教程

packageday0704;

importjava.util.regex.Matcher;

importjava.util.regex.Pattern;

/**

 * 驼峰法-下划线互转

 * @author cshaper

 * @since 2015.07.04

 * @version 1.0.0

 */

publicclassUnderline2Camel {

 /**

  * 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

  */

 publicstaticString underline2Camel(String line,booleansmallCamel){

  if(line==null||"".equals(line)){

   return"";

  }

  StringBuffer sb=newStringBuffer();

  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)));

   intindex=word.lastIndexOf('_');

   if(index>0){

    sb.append(word.substring(1, index).toLowerCase());

   }else{

    sb.append(word.substring(1).toLowerCase());

   }

  }

  returnsb.toString();

 }

 /**

  * 驼峰法转下划线

  * @param line 源字符串

  * @return 转换后的字符串

  */

 publicstaticString camel2Underline(String line){

  if(line==null||"".equals(line)){

   return"";

  }

  line=String.valueOf(line.charAt(0)).toUpperCase().concat(line.substring(1));

  StringBuffer sb=newStringBuffer();

  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()?"":"_");

  }

  returnsb.toString();

 }

 publicstaticvoidmain(String[] args) {

  String line="I_HAVE_AN_IPANG3_PIG";

  String camel=underline2Camel(line,true);

  System.out.println(camel);

  System.out.println(camel2Underline(camel));

 }

}