构建器使用举例-静态工厂和构造器的替代方法

来源：互联网发布：淘宝平台账务处理编辑：程序博客网时间：2024/05/29 07:36

“静态工厂和构造器有个共同的局限性：他们都不能很好的扩展到大量的可选参数。”

下面是构建器的一个举例：

package com.bestcxx.stu.builder;/** * 只能通过构造器方法对实体进行值的修改 * @author Administrator * */public class UserBuilder {private final int number;private final int name;private final  int age;public static class Builder{ private final int number;//设置默认值private int name=0;private int age=0;public Builder(int number){this.number=number;}public Builder name(int val){name=val;return this;}public Builder age(int val){age=val;return this;}public UserBuilder build(){return new UserBuilder(this);}}private UserBuilder(Builder builder){number=builder.number;name=builder.name;age=builder.age;}public static void main(String[] args) {UserBuilder u=new UserBuilder.Builder(1).name(10).age(20).build();System.out.println(u.number);System.out.println(u.age);System.out.println(u.name);}}

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