import com.sun.xml.internal.bind.marshaller.DumbEscapeHandler; //导入依赖的package包/类
protected CharacterEscapeHandler createEscapeHandler( String encoding ) {
    if( escapeHandler!=null )
        // user-specified one takes precedence.
        return escapeHandler;

    if( encoding.startsWith("UTF") )
        // no need for character reference. Use the handler
        // optimized for that pattern.
        return MinimumEscapeHandler.theInstance;

    // otherwise try to find one from the encoding
    try {
        // try new JDK1.4 NIO
        return new NioEscapeHandler( getJavaEncoding(encoding) );
    } catch( Throwable e ) {
        // if that fails, fall back to the dumb mode
        return DumbEscapeHandler.theInstance;
    }
}