漫谈Java实例化类

    Java 中实例化类的动作，你是否还是一成不变 new 对应对象呢？

    经手的项目多了，代码编写量自然会增加，渐渐的会对设计模式产生感觉。

    怎样使书写出来的类实例化动作，高内聚，低耦合，又兼具一定的扩展能力呢？

    本文试图从几段鲜活的代码入手，给大家呈现不一样的 Java 实例化类。

    下面代码取自 com.google.zxing 源码实现：

public BitMatrix encode(String contents, BarcodeFormat format, int width, int height, Map<EncodeHintType, ?> hints) throws WriterException {    Object writer;    switch(format.ordinal()) {    case 1:      writer = new AztecWriter();      break;    case 2:      writer = new CodaBarWriter();      break;    case 3:      writer = new Code39Writer();      break;    case 4:    case 10:    case 13:    case 14:    default:      throw new IllegalArgumentException("No encoder available for format " + format);    case 5:      writer = new Code128Writer();      break;    case 6:      writer = new DataMatrixWriter();      break;    case 7:      writer = new EAN8Writer();      break;    case 8:      writer = new EAN13Writer();      break;    case 9:      writer = new ITFWriter();      break;    case 11:      writer = new PDF417Writer();      break;    case 12:      writer = new QRCodeWriter();      break;    case 15:      writer = new UPCAWriter();      break;    case 16:      writer = new UPCEWriter();    }    return ((Writer)writer).encode(contents, format, width, height, hints);  }

原标题：漫谈Java实例化类

关键词：JAVA