建造者模式定义：


建造者模式（Builder Pattern）又叫生成器模式**，是一种对象构建模式。它可以将复杂对象的建造过程抽象出来（抽象类别），使这个抽象过程的不同实现方法可以构造出不同表现（属性）的对象。
建造者模式是一步一步创建一个复杂的对象的，它允许用户只通过指定复杂对象的类型和内容就可以构建它们，用户不需要直到内部的具体构建细节。

案例代码如下：

PersonBuilder.png

  • ①：Product（产品角色）：一个具体的产品对象。
  • ②：Builder（抽象建造者）：创建一个Product对象的各个部件指定的接口。
  • ③：ConcreateBuilder（具体建造者）：实现接口，构建和装配各个部件。
  • ④：Director（指挥者）：构建一个Builder接口的对象，它主要是用于创建一个复杂的对象。它主要有两个作用
    • Ⅰ：隔离了客户和对象的生产过程；
    • Ⅱ：负责控制产品对象的生产过程。

创建一个具体产品类PersonProduct：

  1. /*具体产品*/
  2. @Data
  3. public class PersonProduct {
  4.     private String head;
  5.     private String body;
  6.     private String armLeft;
  7.     private String armRight;
  8.     private String legLeft;
  9.     private String lefRight;
  10. }

创建一个抽象建造者PersonBuilder：

  1. /*抽象建造者*/
  2. public abstract class PersonBuilder {
  3.     protected PersonProduct personProduct = new PersonProduct();
  5.     public PersonProduct getPersonProduct() {
  6.         return personProduct;
  7.     }
  9.     /*头*/
  10.     public abstract void buildHead();
  11.     /*身*/
  12.     public abstract void buildBody();
  13.     /*左手*/
  14.     public abstract void buildArmLeft();
  15.     /*右手*/
  16.     public abstract void buildArmRight();
  17.     /*左腿*/
  18.     public abstract void buildLegLeft();
  19.     /*右退*/
  20.     public abstract void buildLegRight();
  21. }

创建一个PersonBuilder的具体构建者PersonThinBuilder：

  1. /*具体构建者*/
  2. public class PersonThinBuilder extends PersonBuilder {
  3.     @Override
  4.     public void buildHead() {
  5.         System.out.println("PersonThinBuilder buildHead ...");
  6.         personProduct.setHead("PersonThinBuilder buildHead ...");
  7.     }
  9.     @Override
  10.     public void buildBody() {
  11.         System.out.println("PersonThinBuilder buildBody ...");
  12.         personProduct.setBody("PersonThinBuilder buildBody ...");
  13.     }
  15.     @Override
  16.     public void buildArmLeft() {
  17.         System.out.println("PersonThinBuilder buildArmLeft ...");
  18.         personProduct.setArmLeft("PersonThinBuilder buildArmLeft ...");
  19.     }
  21.     @Override
  22.     public void buildArmRight() {
  23.         System.out.println("PersonThinBuilder buildArmRight ...");
  24.         personProduct.setArmRight("PersonThinBuilder buildArmRight ...");
  25.     }
  27.     @Override
  28.     public void buildLegLeft() {
  29.         System.out.println("PersonThinBuilder buildLegLeft ...");
  30.         personProduct.setLegLeft("PersonThinBuilder buildLegLeft ...");
  31.     }
  33.     @Override
  34.     public void buildLegRight() {
  35.         System.out.println("PersonThinBuilder buildLegRight ...");
  36.         personProduct.setLefRight("PersonThinBuilder buildLegRight ...");
  37.     }
  38. }

创建一个PersonBuilder的具体构建者PersonFatBuilder：

  1. /*具体构建者*/
  2. public class PersonFatBuilder extends PersonBuilder{
  3.     @Override
  4.     public void buildHead() {
  5.         System.out.println("PersonFatBuilder buildHead ...");
  6.         personProduct.setHead("PersonFatBuilder buildHead ...");
  7.     }
  9.     @Override
  10.     public void buildBody() {
  11.         System.out.println("PersonFatBuilder buildBody ...");
  12.         personProduct.setBody("PersonFatBuilder buildBody ...");
  13.     }
  15.     @Override
  16.     public void buildArmLeft() {
  17.         System.out.println("PersonFatBuilder buildArmLeft ...");
  18.         personProduct.setArmLeft("PersonFatBuilder buildArmLeft ...");
  19.     }
  21.     @Override
  22.     public void buildArmRight() {
  23.         System.out.println("PersonFatBuilder buildArmRight ...");
  24.         personProduct.setArmRight("PersonFatBuilder buildArmRight ...");
  25.     }
  27.     @Override
  28.     public void buildLegLeft() {
  29.         System.out.println("PersonFatBuilder buildLegLeft ...");
  30.         personProduct.setLegLeft("PersonFatBuilder buildLegLeft ...");
  31.     }
  33.     @Override
  34.     public void buildLegRight() {
  35.         System.out.println("PersonFatBuilder buildLegRight ...");
  36.         personProduct.setLefRight("PersonFatBuilder buildLegRight ...");
  37.     }
  38. }

创建一个指挥者PersonDirector：

  1. /*指挥者*/
  2. public class PersonDirector {
  3.     private PersonBuilder personBuilder;
  5.     public PersonDirector(PersonBuilder personBuilder) {
  6.         this.personBuilder = personBuilder;
  7.     }
  9.     public void setPersonBuilder(PersonBuilder personBuilder) {
  10.         this.personBuilder = personBuilder;
  11.     }
  13.     /*创建[PersonProduct]对象*/
  14.     public PersonProduct createPerson() {
  15.         personBuilder.buildHead();
  16.         personBuilder.buildBody();
  17.         personBuilder.buildArmLeft();
  18.         personBuilder.buildArmRight();
  19.         personBuilder.buildLegLeft();
  20.         personBuilder.buildLegRight();
  21.         return personBuilder.getPersonProduct();
  22.     }
  23. }

客户端：

  1. /*客户端*/
  2. public class Client {
  3.     public static void main(String[] args) {
  4.         System.out.println("================== Thin Person ===================");
  5.         PersonBuilder personThinBuilder = new PersonThinBuilder();
  6.         PersonDirector director = new PersonDirector(personThinBuilder);
  7.         PersonProduct thinPerson = director.createPerson();
  8.         System.out.println("thinPerson = " + thinPerson);
  10.         System.out.println("================== Fat Person ===================");
  11.         PersonFatBuilder personFatBuilder = new PersonFatBuilder();
  12.         director.setPersonBuilder(personFatBuilder);
  13.         PersonProduct fatPerson = director.createPerson();
  14.         System.out.println("fatPerson = " + fatPerson);
  15.     }
  16. }

具体输出如下：

  1. ================== Thin Person ===================
  2. PersonThinBuilder buildHead ...
  3. PersonThinBuilder buildBody ...
  4. PersonThinBuilder buildArmLeft ...
  5. PersonThinBuilder buildArmRight ...
  6. PersonThinBuilder buildLegLeft ...
  7. PersonThinBuilder buildLegRight ...
  8. thinPerson = PersonProduct(head=PersonThinBuilder buildHead ..., body=PersonThinBuilder buildBody ..., armLeft=PersonThinBuilder buildArmLeft ..., armRight=PersonThinBuilder buildArmRight ..., legLeft=PersonThinBuilder buildLegLeft ..., lefRight=PersonThinBuilder buildLegRight ...)
  9. ================== Fat Person ===================
  10. PersonFatBuilder buildHead ...
  11. PersonFatBuilder buildBody ...
  12. PersonFatBuilder buildArmLeft ...
  13. PersonFatBuilder buildArmRight ...
  14. PersonFatBuilder buildLegLeft ...
  15. PersonFatBuilder buildLegRight ...
  16. fatPerson = PersonProduct(head=PersonFatBuilder buildHead ..., body=PersonFatBuilder buildBody ..., armLeft=PersonFatBuilder buildArmLeft ..., armRight=PersonFatBuilder buildArmRight ..., legLeft=PersonFatBuilder buildLegLeft ..., lefRight=PersonFatBuilder buildLegRight ...)