编码器-->toUnicode

public class Encoder {

public static String toUnicode ( String input ) {

StringBuilder builder = new StringBuilder();
char[] chars = input.toCharArray();

for ( char ch : chars ) {

if ( ch < 256 ) {
builder.append( ch );
} else {
builder.append( "\\u" +  Integer.toHexString( ch& 0xffff ) );
}

}

return builder.toString();

}

}