java读取配置文件(properties)的时候,unicode码转utf-8

/**
* 将配置文件中的Unicode 转 utf-8 汉字
* @param 原始字符串
* @return  转换后的格式的字符串
*/
public static String unicodeToChina(String str) {
Charset set = Charset.forName("UTF-16");
Pattern p = Pattern.compile("\\\\u([0-9a-fA-F]{4})");
Matcher m = p.matcher( str );
int start = 0 ;
int start2 = 0 ;
StringBuffer sb = new StringBuffer();
while( m.find( start ) ) {
start2 = m.start() ;
if( start2 > start ){
String seg = str.substring(start, start2) ;
sb.append( seg );
}
String code = m.group( 1 );
int i = Integer.valueOf( code , 16 );
byte[] bb = new byte[ 4 ] ;
bb[ 0 ] = (byte) ((i >> 8) & 0xFF );
bb[ 1 ] = (byte) ( i & 0xFF ) ;
ByteBuffer b = ByteBuffer.wrap(bb);
sb.append( String.valueOf( set.decode(b) ).trim() );
start = m.end() ;
}
start2 = str.length() ;
if( start2 > start ){
String seg = str.substring(start, start2) ;
sb.append( seg );
}
return sb.toString() ;
}

public static void main(String[] args) {
String str = unicodeToChina("\u672a\u6765");
System.out.println(str);
}