建造者模式和工厂模式的区别

它们目的都是创建一个复杂的对象

工厂模式注重的是整体对象的创建方法，而建造者模式注重的是对象的创建过程，创建对象的过程方法可以在创建时自由调用。

看一下建造者模式的例子就明白了：

public class EmployeeBuilder
{
    private int id = 1;
    private string firstname = "first";
    private string lastname = "last";
    private DateTime birthdate = DateTime.Today;
    private string street = "street";

    public Employee Build()
    {
        return new Employee(id, firstname, lastname, birthdate, street);
    }

    public EmployeeBuilder WithFirstName(string firstname)
    {
        this.firstname = firstname;
        return this;
    }

    public EmployeeBuilder WithLastName(string lastname)
    {
        this.lastname = lastname;
        return this;
    }

    public EmployeeBuilder WithBirthDate(DateTime birthdate)
    {
        this.birthdate = birthdate;
        return this;
    }

    public EmployeeBuilder WithStreet(string street)
    {
        this.street = street;
        return this;
    }

    public static implicit operator Employee(EmployeeBuilder instance)
    {
        return instance.Build();
    }
}

调用：

void main(){
Employee emp1 = new EmployeeBuilder().WithFirstName("Kenneth")
                                            .WithLastName("Truyers");

Employee emp2 = new EmployeeBuilder().WithBirthDate(new DateTime(1983, 1,1));
}