java读取配置文件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);  
    }

person.last-name=哈哈
person.age=18
person.bitrh=2019/01/12
person.boss=false
person.maps.ke1=v1
person.maps.k2=13
person.lists=a,b,c,d
person.dog.name=tom
person.dog.age=15