Java Builder模式实现原理及优缺点解析

/**
 * 家装对象类
 */
public class House {
  // 买家电
  private String jiadian;

  // 买地板
  private String diban;
  // 买油漆
  private String youqi;

  public String getJiadian() {
    return jiadian;
  }

  public void setJiadian(String jiadian) {
    this.jiadian = jiadian;
  }

  public String getDiban() {
    return diban;
  }

  public void setDiban(String diban) {
    this.diban = diban;
  }

  public String getYouqi() {
    return youqi;
  }

  public void setYouqi(String youqi) {
    this.youqi = youqi;
  }

  @Override
  public String toString() {
    return "House{" +
        "jiadian='" + jiadian + '\'' +
        ", diban='" + diban + '\'' +
        ", youqi='" + youqi + '\'' +
        '}';
  }
}

/**
 * 抽象建造者
 */
public interface HouseBuilder {
  // 买家电
  void doJiadian();
  // 买地板
  void doDiBan();
  // 买油漆
  void doYouqi();

  House getHouse();
}

/**
 * 简装创建者
 */
public class JianzhuangBuilder implements HouseBuilder {

  private House house = new House();

  @Override
  public void doJiadian() {
    house.setJiadian("简单家电就好");
  }

  @Override
  public void doDiBan() {
    house.setDiban("普通地板");
  }

  @Override
  public void doYouqi() {
    house.setYouqi("污染较小的油漆就行");
  }

  @Override
  public House getHouse() {
    return house;
  }
}

/**
 * 精装创建者
 */
public class jingzhuangBuilder implements HouseBuilder {

  private House house = new House();

  @Override
  public void doJiadian() {
    house.setJiadian("二话不说，最好的");
  }

  @Override
  public void doDiBan() {
    house.setDiban("二话不说，实木地板");
  }

  @Override
  public void doYouqi() {
    house.setYouqi("二话不说，给我来0污染的");
  }

  @Override
  public House getHouse() {
    return house;
  }
}

/**
 * 家装公司，值需要告诉他精装还是简装
 */
public class HouseDirector {

  public House builder(HouseBuilder houseBuilder){
    houseBuilder.doDiBan();
    houseBuilder.doJiadian();
    houseBuilder.doYouqi();
    return houseBuilder.getHouse();
  }
}

public class App {
  public static void main(String[] args) {
    house();
  }

  public static void house(){
    HouseDirector houseDirector = new HouseDirector();
    // 简装
    JianzhuangBuilder jianzhuangBuilder = new JianzhuangBuilder();
    System.out.println("我要简装");
    System.out.println(houseDirector.builder(jianzhuangBuilder));

    // 精装
    jingzhuangBuilder jingzhuangBuilder = new jingzhuangBuilder();
    System.out.println("我要精装");
    System.out.println(houseDirector.builder(jingzhuangBuilder));

  }
}

return new Docket(DocumentationType.SWAGGER_2)
    .apiInfo(apiInfo())
    .select()
    .apis(RequestHandlerSelectors.basePackage("com.curry.springbootswagger.controller"))
    .paths(PathSelectors.any())
    .build();

public class Student {

  private String name;

  private int age;

  private int num;

  private String email;

  // 提供一个静态builder方法
  public static Student.Builder builder() {
    return new Student.Builder();
  }
  // 外部调用builder类的属性接口进行设值。
  public static class Builder{
    private String name;

    private int age;

    private int num;

    private String email;

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

    public Builder age(int age) {
      this.age = age;
      return this;
    }

    public Builder num(int num) {
      this.num = num;
      return this;
    }

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

    public Student build() {
      // 将builder对象传入到学生构造函数
      return new Student(this);
    }
  }
  // 私有化构造器
  private Student(Builder builder) {
    name = builder.name;
    age = builder.age;
    num = builder.num;
    email = builder.email;
  }

  @Override
  public String toString() {
    return "Student{" +
        "name='" + name + '\'' +
        ", age=" + age +
        ", num=" + num +
        ", email='" + email + '\'' +
        '}';
  }
}

  public static void student(){
    Student student = Student.builder().name("平头哥").num(1).age(18).email("平头哥@163.com").build();
    System.out.println(student);
  }