java8 找出最重的苹果名称找出最重的名子最重

今天药忘吃喽~ 2023-06-15 07:21 11阅读 0赞

[java8 找出最重的苹果名称 找出最重的名子 最重][java8 _ _]

import java.time.LocalDate;
    import java.util.ArrayList;
    import java.util.Comparator;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    import java.util.Optional;
    import java.util.stream.Collectors;
    
    /**
     * @author InJavaWeTrust
     */
    public class TestB {
    
    	public static void main(String[] args) {
    		Apple apple1 = new Apple("红富士", 45, "红", "辽宁", LocalDate.of(2019, 10, 12));
    		Apple apple2 = new Apple("国光", 60, "绿", "河北", LocalDate.of(2019, 10, 18));
    		Apple apple3 = new Apple("红星", 50, "红", "山东", LocalDate.of(2019, 9, 10));
    		Apple apple4 = new Apple("黄元帅", 85, "黄", "山东", LocalDate.of(2019, 10, 6));
    		Apple apple5 = new Apple("嘎啦", 35, "绿", "山东", LocalDate.of(2019, 8, 21));
    		Apple apple6 = new Apple("寒富", 40, "红", "辽宁", LocalDate.of(2019, 9, 20));
    		List<Apple> appleList = new ArrayList<>();
    		appleList.add(apple1);
    		appleList.add(apple2);
    		appleList.add(apple3);
    		appleList.add(apple4);
    		appleList.add(apple5);
    		appleList.add(apple6);
    		
    		//找出最重的苹果品种
    		Map<String, Integer> appleVariety = new HashMap<>();
    		
    		appleList.stream().collect(Collectors.groupingBy(Apple::getVariety))//根据品种分组[品种名称 Apple]
    		.forEach((k, v) -> appleVariety.put(k, v.stream().collect(Collectors.summingInt(Apple::getWeight))));
    		
    		Optional<String> appleOpt = appleVariety.keySet().stream().sorted(Comparator.comparing(appleVariety::get).reversed()).limit(1L).findFirst();
    		if (appleOpt.isPresent()) {
    			System.out.println("最重的苹果名称：" + appleOpt.get());
    		}
    
    	}
    
    }

结果：

最重的苹果名称：黄元帅

import java.time.LocalDate;
    
    /**
     * @author InJavaWeTrust
     */
    public class Apple {
    	
    	private String variety;
    	private int weight;
    	private String color;
    	private String placeOfOrigin;
    	private LocalDate productionDate;
    	
    	public Apple() {
    	}
    	
    	public Apple(String variety, int weight, String color, String placeOfOrigin, LocalDate productionDate) {
    		this.variety = variety;
    		this.weight = weight;
    		this.color = color;
    		this.placeOfOrigin = placeOfOrigin;
    		this.productionDate = productionDate;
    	}
    
    	public String getVariety() {
    		return variety;
    	}
    	public void setVariety(String variety) {
    		this.variety = variety;
    	}
    	public int getWeight() {
    		return weight;
    	}
    	public void setWeight(int weight) {
    		this.weight = weight;
    	}
    	public String getColor() {
    		return color;
    	}
    	public void setColor(String color) {
    		this.color = color;
    	}
    	public String getPlaceOfOrigin() {
    		return placeOfOrigin;
    	}
    	public void setPlaceOfOrigin(String placeOfOrigin) {
    		this.placeOfOrigin = placeOfOrigin;
    	}
    	public LocalDate getProductionDate() {
    		return productionDate;
    	}
    	public void setProductionDate(LocalDate productionDate) {
    		this.productionDate = productionDate;
    	}
    	
    	@Override
    	public String toString() {
    		return "Apple ["
    				+ "variety="        + variety        + ", "
    				+ "weight="         + weight         + ", "
    				+ "color="          + color          + ", "
    				+ "placeOfOrigin="  + placeOfOrigin  + ", "
    				+ "productionDate=" + productionDate + 
    				"]";
    	}
    	
    }

[java8 _ _]: https://blog.csdn.net/InJavaWeTrust/article/details/103180418