建造者模式

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。

比如：StringBuilder

实际案例

类信息概览：

类名 说明
Main.java 方法的总入口
PersonGirlBuilder.java  
PersonBoyBuilder.java  
Person.java  
PersonBuilder.java  
PersonDirector.java  

定义

  • PersonGirlBuilder.java
package com.ryo.design.pattern.note.builder;

/**
 * Created by bbhou on 2017/8/9.
 */
public class PersonGirlBuilder implements PersonBuilder {
    @Override
    public String buildName() {
        return "rose";
    }

    @Override
    public int buildAge() {
        return 19;
    }

    @Override
    public String buildSex() {
        return "girl";
    }
}
  • PersonBoyBuilder.java
package com.ryo.design.pattern.note.builder;

/**
 * Created by bbhou on 2017/8/9.
 */
public class PersonBoyBuilder implements PersonBuilder {
    @Override
    public String buildName() {
        return "jack";
    }

    @Override
    public int buildAge() {
        return 20;
    }

    @Override
    public String buildSex() {
        return "boy";
    }
}
  • Person.java
package com.ryo.design.pattern.note.builder;

import lombok.Data;

/**
 * Created by bbhou on 2017/8/9.
 */
@Data
public class Person {

    /**
     * 名称
     */
    private String name;

    /**
     * 年龄
     */
    private int age;

    /**
     * 性别
     */
    private String sex;

}
  • PersonBuilder.java
package com.ryo.design.pattern.note.builder;

/**
 * Created by bbhou on 2017/8/9.
 */
public interface PersonBuilder {

    /**
     * 构建名称
     * @return
     */
    String buildName();

    /**
     * 构建年龄
     * @return
     */
    int buildAge();

    /**
     * 构建性别
     * @return
     */
    String buildSex();

}
  • PersonDirector.java
package com.ryo.design.pattern.note.builder;


/**
 * Created by bbhou on 2017/8/9.
 */
public class PersonDirector {

    private PersonBuilder personBuilder;

    public PersonDirector(PersonBuilder personBuilder) {
        this.personBuilder = personBuilder;
    }

    /**
     * 创建一个人
     * @return
     */
    Person createPerson() {
        Person person = new Person();
        person.setAge(personBuilder.buildAge());
        person.setName(personBuilder.buildName());
        person.setSex(personBuilder.buildSex());
        return person;
    }

}

测试

  • Main.java
/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * Copyright (c) 2012-2018. houbinbini Inc.
 * design-pattern All rights reserved.
 */

package com.ryo.design.pattern.note.builder;

/**
 * <p> </p>
 *
 * <pre> Created: 2018/5/9 下午7:45  </pre>
 * <pre> Project: design-pattern  </pre>
 *
 * @author houbinbin
 * @version 1.0
 * @since JDK 1.7
 */
public class Main {

    public static void main(String[] args) {
        PersonDirector personDirector = new PersonDirector(new PersonBoyBuilder());
        Person person = personDirector.createPerson();
        System.out.println(person);
    }

}
  • 测试结果
Person(name=jack, age=20, sex=boy)

实现方式

UML & Code

UML

UML 图示如下

Code

代码地址

建造者模式

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