建造者模式（Builder Pattern）使用多个简单的对象一步一步构建成一个复杂的对象。这种类型的设计模式属于创建型模式，它提供了一种创建对象的最佳方式。

一个 Builder 类会一步一步构造最终的对象。该 Builder 类是独立于其他对象的。

代码实现

package builder//Builder 是生成器接口
type Builder interface {Part1()Part2()Part3()
}type Director struct {builder Builder
}// NewDirector ...
func NewDirector(builder Builder) *Director {return &Director{builder: builder,}
}//Construct Product
func (d *Director) Construct() {d.builder.Part1()d.builder.Part2()d.builder.Part3()
}type Builder1 struct {result string
}func (b *Builder1) Part1() {b.result += "1"
}func (b *Builder1) Part2() {b.result += "2"
}func (b *Builder1) Part3() {b.result += "3"
}func (b *Builder1) GetResult() string {return b.result
}type Builder2 struct {result int
}func (b *Builder2) Part1() {b.result += 1
}func (b *Builder2) Part2() {b.result += 2
}func (b *Builder2) Part3() {b.result += 3
}func (b *Builder2) GetResult() int {return b.result
}

单元测试

package builderimport "testing"func TestBuilder1(t *testing.T) {builder := &Builder1{}director := NewDirector(builder)director.Construct()res := builder.GetResult()if res != "123" {t.Fatalf("Builder1 fail expect 123 acture %s", res)}
}func TestBuilder2(t *testing.T) {builder := &Builder2{}director := NewDirector(builder)director.Construct()res := builder.GetResult()if res != 6 {t.Fatalf("Builder2 fail expect 6 acture %d", res)}
}