建造者模式将一个复杂对象的创建和它的表示分离，使用同样的创建过程可以创建不同的表示
应用实例
在Java中，建造者模式是一种常见的设计模式，StringBuilder以及okhttp3.Request都应用了建造者模式：
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("https://www.linuxidc.com")
.build();
实现
我们将要实现一个Human类的建造者模式实现。
首先创建Human类
public class Human {
private String name;
private int age;
private int weight;
private int height;
//-----------Setter and Getter--------------------
public String getName() { return name; }
public void setName(String name) { this.name = name; }
public int getAge() { return age; }
public void setAge(int age) { this.age = age; }
public int getWeight() { return weight; }
public void setWeight(int weight) { this.weight = weight; }
public int getHeight() { return height; }
public void setHeight(int height) { this.height = height; }
//-----------Setter and Getter--------------------
@Override
public String toString(){
return getName() + " 的年龄是 " + getAge() +
" 的体重是 " + getWeight() + " 的身高是 " +getHeight();
}
}
创建Builder接口
public interface Builder {
Builder setAge(int age);
Builder setName(String name);
Builder setWeight(int weight);
Builder setHeight(int height);
Human build();
}
创建ConcreteBuilder类，使用这个类可以构建Human对象
public class ConcreteBuilder implements Builder {
private Human human;
@Override
public Builder setAge(int age) {
this.human.setAge(age);
return this;
}
@Override
public Builder setName(String name) {
this.human.setName(name);
return this;
}
@Override
public Builder setWeight(int weight) {
this.human.setWeight(weight);
return this;
}
@Override
public Builder setHeight(int height) {
this.human.setHeight(height);
return this;
}
@Override
public Human build() {
return this.human;
}
public ConcreteBuilder(){
this.human = new Human();
}
}
使用演示
public class BuilderDemo {
public static void main(String[] args){
Human human = new ConcreteBuilder()
.setAge(21)
.setName("Amos")
.setHeight(176)
.setWeight(130)
.build();
System.out.println(human);
}
}
它的输出为：
Amos 的年龄是 21 的体重是 130 的身高是 176
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