准备工作

interface Product{
    void method();
}
class ProductA implements Product{

    @Override
    public void method() {
        System.out.println("ProductA.method executed.");
    }
}
class ProductA1 implements Product{

    @Override
    public void method() {
        System.out.println("ProductA1.method executed.");
    }
}

简单工厂模式

//简单工厂模式：将实例化过程封装
class SimpleFactory{
    public static Product createProduct(String type){
        switch (type){
            case "0":
                return new ProductA();
            case "1":
                return new ProductA1();
            default:
                return null;
        }
    }
}
class Application{
    public Product createProduct(String type){
        return SimpleFactory.createProduct(type);
    }
}

测试

public class FactoryMethod {
    public static void main(String[] args) {
        Application application = new Application();
        Product product = application.createProduct("0");
        //Product product = application.createProduct("1");
        product.method();
    }
}

运行结果

运行结果

工厂方法模式

//工厂方法模式：将实例化过程交给子类执行
interface Application {
    Product createProduct();
}
class ConCreateProductA implements Application{
    @Override
    public Product createProduct() {
        return new ProductA();
    }
}
class ConCreateProductA1 implements Application{
    @Override
    public Product createProduct() {
        return new ProductA1();
    }
}

测试

public class FactoryMethod {
    public static void main(String[] args) {
       //Application application = new ConCreateProductA();
        Application application = new ConCreateProductA1();
        Product product = application.createProduct();
        product.method();
    }
}

运行结果

运行结果

抽象工厂模式

准备工作

//抽象工厂方法：提供一个创建一系列相关或互相依赖的接口，而无需考虑具体的类
interface IConnection{
    void connect();
}
interface ICommend{
    void commend();
}
interface IDatabaseUtils{
    IConnection getConnection();
    ICommend getCommend();
}

具体实现1

//Mysql建立连接与发送命令
class MysqlConnection implements IConnection{
    @Override
    public void connect() {
        System.out.println("mysql.connected");
    }
}
class MysqlCommend implements ICommend{
    @Override
    public void commend() {
        System.out.println("mysql.commend");
    }
}
class MysqlUtils implements IDatabaseUtils{
    @Override
    public IConnection getConnection() {
        return new MysqlConnection();
    }

    @Override
    public ICommend getCommend() {
        return new MysqlCommend();
    }
}

具体实现2

//Oracle建立连接与发送命令
class OracleConnection implements IConnection{
    @Override
    public void connect() {
        System.out.println("oracle.connected");
    }
}
class OracleCommend implements ICommend{
    @Override
    public void commend() {
        System.out.println("oracle.commend");
    }
}
class OracleUtils implements IDatabaseUtils{
    @Override
    public IConnection getConnection() {
        return new OracleConnection();
    }

    @Override
    public ICommend getCommend() {
        return new OracleCommend();
    }

测试

public class AbstractFactoryDemo {
    public static void main(String[] args) {
        //IDatabaseUtils databaseUtils = new MysqlUtils();
        IDatabaseUtils databaseUtils = new OracleUtils();

        IConnection connection = databaseUtils.getConnection();
        connection.connect();
        final ICommend commend = databaseUtils.getCommend();
        commend.commend();
    }
}

运行结果

运行结果