工厂模式 属于创建型模式
类图
通过一个工厂类,以一个条件来创建对应的对象
//业务功能 public interface ICalculation { double getResult(double numA, double numB); }
public class CalcAdd implements ICalculation { @Override public double getResult(double numA, double numB) { System.out.println("加法"); return numA + numB; } }
public class CalcSubtract implements ICalculation { @Override public double getResult(double numA, double numB) { System.out.println("减法"); return numA - numB; } }
/* * 简单工厂模式 关注:对象的创建 * 建立一个工厂类,对实现了同一接口的或者是存在继承关系的一些类进行实例的创建 */ public class Test4Simple { public static void main(String[] args) { // String operation = "/"; String operation = "+"; // String operation = "-"; // String operation = "*"; double numA = 182, numB = 33; ICalculation createCalc = CalcSimpleFactory.createCalc(operation); double result = createCalc.getResult(numA, numB); System.out.println(result); } }
简单工厂的缺陷: 简单工厂创建产品时需要传递相应的参数,如果传递不正确就取不到对象了。
改进:多方法创建不同产品
类图
public class CalcMultipleFactory { public static ICalculation produceAdd() { return new CalcAdd(); } public static ICalculation produceSubtract() { return new CalcSubtract(); } public static ICalculation produceMultiply() { return new CalcMultiply(); } public static ICalculation producepide() { return new Calcpide(); } }
public class Test4Multiple { public static void main(String[] args) { double numA = 182, numB = 33; ICalculation createCalc = CalcMultipleFactory.produceAdd(); double result = createCalc.getResult(numA, numB); System.out.println(result); createCalc = CalcMultipleFactory.produceSubtract(); result = createCalc.getResult(numA, numB); System.out.println(result); createCalc = CalcMultipleFactory.produceMultiply(); result = createCalc.getResult(numA, numB); System.out.println(result); createCalc = CalcMultipleFactory.producepide(); result = createCalc.getResult(numA, numB); System.out.println(result); } }
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