设计模式:建造者模式（builder）

最新推荐文章于 2025-09-01 22:41:54 发布

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本文介绍了一种在Java中实现Builder模式的方法，通过实例演示了如何使用该模式简化对象的创建过程，尤其是在面对拥有多个可选参数的对象时。

/**
* 使用场景之一：当初始化一个对象特别复杂，参数较多，但很多参数都有默认值时。
*/

/**
* @Author : haojiangt
* @Description :builder模式
**/

public class BuilderTest {
    @Test
    public void test1(){
        StringBuilder sb = new StringBuilder();
        sb.append("a").append("b").append("c");
        System.out.println(sb);
    }
}

public class TsetBean {
    private String name;
    private Integer age;
    private String addr;
    private String phone;
    private String desc;

    public String getName() {
        return name;
    }

    public Integer getAge() {
        return age;
    }

    public String getAddr() {
        return addr;
    }

    public String getPhone() {
        return phone;
    }

    public String getDesc() {
        return desc;
    }

   public void setName(String name) {
        this.name = name;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public void setAddr(String addr) {
        this.addr = addr;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

   /**
     * 第一种方式：构造方法（重叠构造方法）
     */
    public TsetBean(String name, Integer age) {
        this(name, age, null, null, null);
    }

    public TsetBean(String name, Integer age, String addr) {
        this(name, age, addr, null, null);
    }

    public TsetBean(String name, Integer age, String addr, String phone) {
        this(name, age, addr, phone, null);
    }
    public TsetBean(String name, Integer age, String addr, String phone, String desc) {
        this.name = name;
        this.age = age;
        this.addr = addr;
        this.phone = phone;
        this.desc = desc;
    }

   //第二种builder模式

    public TsetBean(Builder builder) {
        this.name = builder.name;
        this.age = builder.age;
        this.phone = builder.phone;
        this.addr = builder.addr;
        this.desc = builder.phone;
    }

    public static class Builder{
        //必要参数
        private String name;
        private Integer age;
        //可选参数
        private String addr;
        private String phone;
        private String desc;
       public Builder(String name, Integer age) {
            this.name = name;
            this.age = age;
        }

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

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

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

        public TsetBean build(){
            return new TsetBean(this);
        }
    }
   //
    @Override
    public String toString() {
        return "TsetBean{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", addr='" + addr + '\'' +
                ", phone='" + phone + '\'' +
                ", desc='" + desc + '\'' +
                '}';
    }

    public static void main(String[] args){
        TsetBean zhang = new TsetBean.Builder("zhang", 15)
                .addr("莲花街")
                .desc("阳光开朗")
                .phone("12452718").build();
        System.out.println(zhang.toString());
       //out: TsetBean{name='zhang', age=15, addr='莲花街', phone='12452718', desc='12452718'}
   }
}