[移动开发]Java Lambda 分区方法再添加分组收集器

Java Lambda 分区方法再添加分组收集器

public class Menu {
	
	/**
	 * 菜品名称
	 */
	private String name;
	/**
	 * 菜品单价
	 */
	private Double price;
	/**
	 * 菜品斤数
	 */
	private Double kilo;
	/**
	 * 菜品类型：蔬菜、水果、肉类
	 */
	private String type;
	
	public Menu() {
		
	}

	public Menu(String name, Double price, Double kilo, String type) {
		super();
		this.name = name;
		this.price = price;
		this.kilo = kilo;
		this.type = type;
	}

	public String getName() {
		return name;
	}

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

	public Double getPrice() {
		return price;
	}

	public void setPrice(Double price) {
		this.price = price;
	}

	public Double getKilo() {
		return kilo;
	}

	public void setKilo(Double kilo) {
		this.kilo = kilo;
	}

	public String getType() {
		return type;
	}

	public void setType(String type) {
		this.type = type;
	}
	
	
}

Menu pork    = new Menu("猪肉", 9.9, 10.0, "肉类");
Menu beef    = new Menu("牛肉", 38.8, 5.0, "肉类");
Menu chicken = new Menu("鸡肉", 6.5, 30.0, "肉类");
Menu tomato  = new Menu("土豆", 3.5, 30.0, "蔬菜");
Menu potato  = new Menu("西红柿", 7.5, 20.0, "蔬菜");
Menu apple   = new Menu("苹果", 3.5, 20.0, "水果");
Menu orange  = new Menu("橙子", 4.0, 20.0, "水果");
List<Menu> menuList = Arrays.asList(pork, beef, chicken, tomato, potato, apple, orange);

//获取便宜菜品分区，按菜品种类分组
Map<Boolean,Map<String, List<Menu>>> map = menuList.stream().collect(Collectors.partitioningBy(menu -> {
	if (menu.getPrice() >= 10.0) {
		return true;
	} else {
		return false;
	}
}, Collectors.groupingBy(Menu::getType)));

Map<String, List<Menu>> m = map.get(false);
m.forEach((key, value) -> {
	System.out.println(key);
	value.forEach(me -> {
		System.out.println("----->" + me.getName());
	});
});

蔬菜
----->土豆
----->西红柿
肉类
----->猪肉
----->鸡肉
水果
----->苹果
----->橙子

//分别获取最贵、最便宜菜品中最大斤数菜品信息
Map<Boolean, Menu> map = menuList.stream().collect(Collectors.partitioningBy(menu -> {
	if (menu.getPrice() >= 10.0) {
		return true;
	} else {
		return false;
	}
}, Collectors.collectingAndThen(Collectors.maxBy(Comparator.comparing(Menu::getKilo)), Optional::get)));

map.forEach((key, value) -> {
	System.out.println(key + " " + value.getName() + " " + value.getKilo());
});

false 鸡肉 30.0
true 牛肉 5.0