设计模式

策略模式

示例代码

public class TestMain {
    public static void main(String[] args) {
        Computer computer = new Computer();
        AddComputer addComputer = new AddComputer();
        SubComputer subComputer = new SubComputer();

        computer
                .setOperation(subComputer);
        System.out.println(computer.doOperation(1, 2));
    }
}

接口

public interface Operation {

    public int calculate(int n1, int n2);

}

具体算法实现类

public class AddComputer implements Operation{
    @Override
    public int calculate(int n1, int n2) {
        return n1 + n2;
    }
}
public class SubComputer implements Operation{
    @Override
    public int calculate(int n1, int n2) {
        return n1 - n2;
    }
}

操作类

public class Computer {

    private Operation operation;

    public void setOperation(Operation operation) {
        this.operation = operation;
    }

    public int doOperation(int n1, int n2){
        return this.operation.calculate(n1, n2);
    }

}

建造者模式

示例代码

public class Product {
    private String attribute1;
    private String attribute2;
    private String attribute3;

    private Product(Builder builder) {
        this.attribute1 = builder.attribute1;
        this.attribute2 = builder.attribute2;
        this.attribute3 = builder.attribute3;
    }

    // Getter methods

    public static class Builder {
        private String attribute1;
        private String attribute2;
        private String attribute3;

        public Builder attribute1(String value) {
            this.attribute1 = value;
            return this;
        }

        public Builder attribute2(String value) {
            this.attribute2 = value;
            return this;
        }

        public Builder attribute3(String value) {
            this.attribute3 = value;
            return this;
        }

        public Product build() {
            return new Product(this);
        }
    }
}

用法

Product product = new Product.Builder()
                        .attribute1("Value 1")
                        .attribute2("Value 2")
                        .attribute3("Value 3")
                        .build();