//此总结为个人原创，有任何问题欢迎指出并改正，谢谢支持
使用场景：计划在不同的场景下创建不同的产品；分为简单工厂和抽象工厂
两种设计模式的区别：
区别在于产品，如果产品单一，最合适用工厂模式，但是如果有多个业务品种、业务分类时，通过抽象工厂模式产生需要的对象是一种非常好的解决方式。再通俗深化理解下：工厂模式针对的是一个产品等级结构，抽象工厂模式针对的是面向多个产品等级结构的。
简单工厂方法模式Demo：
抽象产品接口
public interface Operation{
public double getResult(double numberA,double numberB)throws Exception;
}
具体产品接口
public class Add implements Operation{ // 加法计算
public double getResult(double numberA, double numberB){return numberA + numberB;}}public class Sub implements Operation{ // 减法计算public double getResult(double numberA, double numberB){return numberA-numberB;}}
public class Mul implements Operation{// 乘法计算
public double getResult(double numberA, double numberB){
return numberA * numberB;
}
}public class Div implements Operation{// 除法计算
public double getResult(double numberA, double numberB)throws Exception {
if(numberB == 0) {throw new Exception("除数不能为0！");}return numberA / numberB;}}
简单工厂类
public class EasyFactory{ // 简单工厂，根据字符串创建相应的对象
publicstatic Operation createOperation(String name){
Operation operationObj = null; switch(name) { case"+":
operationObj = new Add(); break; case"-": operationObj = new Sub(); break; case"*": operationObj = new Mul(); break; case"/": operationObj = new Div(); break; } return operationObj; }}客户端调用：
public class Client{
public static void main(String[] args) throws Exception {
Operation add = EasyFactory.createOperation("+"); Operation sub = EasyFactory.createOperation("-"); Operation mul = EasyFactory.createOperation("*"); Operation div = EasyFactory.createOperation("/"); System.out.println(add.getResult(1, 1)); System.out.println(sub.getResult(1, 1)); System.out.println(mul.getResult(1, 1)); System.out.println(div.getResult(1, 1)); }}*****************
可以对简单工厂进行改良
public class EasyFactory{
private static Operation operationObj = null;
private static Operation add(){
System.out.println("加法运算");return new Add();
} privatestatic Operation sub(){System.out.println("减法运算");return new Sub();
} private static Operation mul(){System.out.println("乘法运算");
return new Mul();
} private static Operation div(){
System.out.println("除法运算");return new Div();}
// 简单工厂，根据字符串创建相应的对象
publicstatic Operation createOperation(String name){
switch (name) {
case"+": operationObj = add(); break; case"-": operationObj = sub(); break; case"*": operationObj = mul(); break; case"/": operationObj = div(); break; } return operationObj; }}抽象工厂方法模式Demo：
产品类不变，只抽象工厂类
抽象工厂类
public interface Factory{
public Operation createOperation();
}
具体工厂类
// 加法类工厂
public class AddFactory implements Factory{
public Operation createOperation(){
System.out.println("加法运算"); return new Add(); }}
// 减法类工厂
public class SubFactory implements Factory{public Operation createOperation(){System.out.println("减法运算");return new Sub();
}}
// 乘法类工厂
public class MulFactory implements Factory{
public Operation createOperation(){System.out.println("乘法运算");return new Mul();
}}// 除法类工厂
public class DivFactory implements Factory{
public Operation createOperation(){
System.out.println("除法运算"); return new Div();
}}
客户端代码：
public class Client{
public static void main(String[] args)throws Exception {
// 使用反射机制实例化工厂对象，因为字符串是可以通过变量改变的
Factory addFactory = (Factory) Class.forName("org.zero01.factory.AddFactory").newInstance(); Factory subFactory=(Factory) Class.forName("org.zero01.factory.SubFactory").newInstance(); Factory mulFactory=(Factory) Class.forName("org.zero01.factory.MulFactory").newInstance(); Factory divFactory=(Factory) Class.forName("org.zero01.factory.DivFactory").newInstance(); // 通过工厂对象创建相应的实例对象
Operation add = addFactory.createOperation(); Operation sub = subFactory.createOperation(); Operation mul = mulFactory.createOperation(); Operation div = divFactory.createOperation(); System.out.println(add.getResult(1, 1)); System.out.println(sub.getResult(1, 1)); System.out.println(mul.getResult(1, 1)); System.out.println(div.getResult(1, 1)); }}*******************************
抽象工厂类可以改良（代码中常用）如下：
public abstract class Factroy{ public abstract<T extends Operation > T create(Class<T> clz); } public class BaseFactory extends Factroy{ @override public <T extends Operation > T create(Class<T> clz){ Operation shape=null; try{
shape=(Operation)Class.forName(clz.getName()).newInstance(); } catch(Exception e){ e.printStackTrace(); } return (T)shape; } }
客户端调用
public class Client{
public static void main(String[] args)throws Exception {
Factory factory=new BaseFactory(); Factory addFactory =factory.create(AddFactory.class); Factory subFactory =factory.create(SubFactory.class); Factory mulFactory =factory.create(MulFactory.class); Factory divFactory =factory.create(DivFactory.class); // 通过工厂对象创建相应的实例对象
Operation add = addFactory.createOperation(); Operation sub = subFactory.createOperation(); Operation mul = mulFactory.createOperation(); Operation div = divFactory.createOperation(); System.out.println(add.getResult(1, 1)); System.out.println(sub.getResult(1, 1)); System.out.println(mul.getResult(1, 1)); System.out.println(div.getResult(1, 1)); }}