利用Builder方式创建对象示例代码

前言

在创建对象需要初始化数据，数据参数不容易区别，可传可不传的时候，可以考虑使用builder建造方法创建。每每当看到别人写的用bulder方式来调用，就觉得so cool，那就自己也来用builder方式创建对象吧。

下面话不多说了，来一起看看详细的介绍吧

现在要录入一系列人员的基本信息的示例：

创建person类

public class person {
private string name;
private int age;
private float height;
private float weight;

public person(string name, int age, float height, float weight) {
this.name = name;
this.age = age;
this.height = height;
this.weight = weight;
}

public string getname() {
return name;
}

public void setname(string name) {
this.name = name;
}

public int getage() {
return age;
}

public void setage(int age) {
this.age = age;
}

public float getheight() {
return height;
}

public void setheight(float height) {
this.height = height;
}

public float getweight() {
return weight;
}

public void setweight(float weight) {
this.weight = weight;
}
}

那么创建对象就是这样，后面参数不容易看出表示的是什么，可读性不强

new person("冯提莫",18,150,43);
new person("温婉",17,164,48);

用builder模式进行改造

创建一个builder类，属性和person类一样，加上setxxx()方法

static class builder{
private string name;
private int age;
private float height;
private float weight;

public void setname(string name) {
this.name = name;
}

public void setage(int age) {
this.age = age;
}

public void setheight(float height) {
this.height = height;
}

public void setweight(float weight) {
this.weight = weight;
}
}

将person的构造方法改为传入builder对象，将builder对象的属性值都赋予person对象

public person(builder builder){
this.name = builder.name;
this.age = builder.age;
this.height = builder.height;
this.weight = builder.weight;
}

改造builder类，关键步骤是将各个set方法返回builder类对象，这样就能继续愉快地连续调用set方法了，最后调用build()创建方法返回person对象。

static class builder{
private string name;
private int age;
private float height;
private float weight;

public builder setname(string name) {
this.name = name;
return this;
}

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

public builder setheight(float height) {
this.height = height;
return this;
}

public builder setweight(float weight) {
this.weight = weight;
return this;
}

public person build(){
return new person(this);
}
}

将各个set方法的返回值类型改为builder，每次都返回builder对象，这样才能将set方法实现连续的链式调用。

build()方法创建一个person对象，会调用person的带参构造方法，将builder对象的属性依次赋予person对象。person中的属性值就是链式调用set方法的各个值。

使用builder模式创建person对象，明显看出代码可读性大大增强。注：builder创建方式通常是在创建的对象少的情况下使用。

person person = new person.builder()
.setname("莉哥")
.setage(20)
.setheight(162)
.setweight(45)
.build();

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对的支持。