Java采用内部构造器Builder模式进行对类进行构建

好处：

　　能保证重叠构造器模式的安全性；

　　能保证JAVABeans模式的可读性；

package cn.lonecloud.builder;
/**
 * 使用内部类构建器来对这个类进行构造
 * @Title: MyConstractor.java
 * @Package cn.lonecloud.builder
 * @Description:
 * @author lonecloud
 * @webSite http://wwww.lonecloud.cn
 * @date 2016年9月12日 上午10:17:11
 */
public class MyConstractor {

	//some field of class
	private final int size;

	private final int servings;

	private final int fat;

	private final int sodium;

	private final int age;
	//using getMethod
	public int getSize() {
		return size;
	}
	public int getServings() {
		return servings;
	}
	public int getFat() {
		return fat;
	}
	public int getSodium() {
		return sodium;
	}
	public int getAge() {
		return age;
	}

	@Override
	public String toString() {
		return "MyConstractor [size=" + size + ", servings=" + servings
				+ ", fat=" + fat + ", sodium=" + sodium + ", age=" + age + "]";
	}
	//using constractMethod init field
	private MyConstractor(Builder builder){
		this.size=builder.size;
		this.servings=builder.servings;
		this.fat=builder.fat;
		this.sodium=builder.sodium;
		this.age=builder.age;
	}
	//using static class to set this class
	public static class Builder{
		//some field of staticClass
		private final int size;

		private final int servings;
		//using method to set field
		private  int fat=0;

		private  int sodium=0;

		private  int age=0;
		//using constractorMethod to init this final field
		public Builder(int size, int servings) {
			this.size = size;
			this.servings = servings;
		}
		//write method to set field;
		public Builder fat(int fat){
			this.fat=fat;
			return this;
		}
		public Builder sodium(int sodium){
			this.sodium=sodium;
			return this;
		}
		public Builder age(int age){
			this.age=age;
			return this;
		}
		//return MyConstractor
		public MyConstractor build(){
			return new MyConstractor(this);
		}

	}
}

测试类：

package cn.lonecloud.constactor;

import org.junit.Test;

import cn.lonecloud.builder.MyConstractor;

public class MyTest {

	@Test
	public void constractorTest(){
		MyConstractor myConstractor = new MyConstractor.Builder(1,2).age(100).build();
		System.out.println(myConstractor.toString());
	}
}