Builder模式

Posted 2022-03-30 xiangzhahao

还没有看过Builder模式的作用，看过一篇介绍Builder模式的文章，这里是关于Builder模式的思考：思考是否有比新建一个内部类更好的方法，首先想到的是

package xyz.n490808114.test;
public class  BuilderTest
    String name;
    int age;
    int high;
    int weight;
    int speed;

    public BuilderTest name(String name)
        this.name = name;
        return this;
    
    public BuilderTest age(int age)
        this.age = age;
        return this;
    
    public BuilderTest high(int high)
        this.high = high;
        return this;
    
    public BuilderTest weight(int weight)
        this.weight = weight;
        return this;
    
    public BuilderTest speed(int speed)
        this.speed = speed;
        return this;
    
    public void setName(String name)this.name = name;
    public void setAge(int age)this.age = age;
    public void setHigh(int high)this.high = high;
    public void setWeight(int weight)this.weight = weight;
    public void setSpeed(int speed)this.speed = speed;
    public String getName()return this.name;
    public int getAge()return this.age;
    public int getHigh()return this.high;
    public int getWeight()return this.weight;
    public int getSpeed()return this.speed;
    public static void main(String[] args) 
        BuilderTest t = new BuilderTest().age(20).speed(50);
        System.out.println(t.name);
        System.out.println(t.age);
        System.out.println(t.high);
        System.out.println(t.weight);
        System.out.println(t.speed);
    

输出为

null
20
0
0
50

这样感觉跟set方法重复太多，整合一下，如下

package xyz.n490808114.test;
public class  BuilderTest
    String name;
    int age;
    int high;
    int weight;
    int speed;
    public BuilderTest setName(String name)this.name = name;return this;
    public BuilderTest setAge(int age)this.age = age;return this;
    public BuilderTest setHigh(int high)this.high = high;return this;
    public BuilderTest setWeight(int weight)this.weight = weight;return this;
    public BuilderTest setSpeed(int speed)this.speed = speed;return this;
    public String getName()return this.name;
    public int getAge()return this.age;
    public int getHigh()return this.high;
    public int getWeight()return this.weight;
    public int getSpeed()return this.speed;
    public static void main(String[] args) 
        BuilderTest t = new BuilderTest().setAge(20).setSpeed(50);
        System.out.println(t.name);
        System.out.println(t.age);
        System.out.println(t.high);
        System.out.println(t.weight);
        System.out.println(t.speed);
    

这样只是精简代码，只是不知道这样的set方法能不能被spring认可，待测试

能够想到的是：

1，Builder模式用内部类的方法，可以用来修改现有代码，不改动，不新增类的方法，仅在创建时使用内部类；

2，猜测：如果不是频繁创建的话，对性能的影响不大；

3，如果不采用模式，仅使用set方法的话，代码量会多，但是代码会更清晰；

4，Builder模式使代码更易阅读。