Java8---sort

ゝ一纸荒年。 2023-06-04 06:51 33阅读 0赞

package lambdasinaction.chap3;
    
    import java.util.*;
    import static java.util.Comparator.comparing;
    
    public class Sorting { 
    
        public static void main(String...args){ 
    
            // 1
            List<Apple> inventory = new ArrayList<>();
            inventory.addAll(Arrays.asList(new Apple(80,"green"), new Apple(155, "green"), new Apple(120, "red")));
    
            // [Apple{color='green', weight=80}, Apple{color='red', weight=120}, Apple{color='green', weight=155}]
            inventory.sort(new AppleComparator());
            System.out.println(inventory);
    
            // reshuffling things a little
            inventory.set(1, new Apple(30, "green"));
            
            // 2
            // [Apple{color='green', weight=30}, Apple{color='green', weight=80}, Apple{color='green', weight=155}]
            inventory.sort(new Comparator<Apple>() { 
                public int compare(Apple a1, Apple a2){ 
                    return a1.getWeight().compareTo(a2.getWeight()); 
            }});
            System.out.println(inventory);
    
            // reshuffling things a little
            inventory.set(1, new Apple(20, "red"));
            
            // 3
            // [Apple{color='red', weight=20}, Apple{color='green', weight=30}, Apple{color='green', weight=155}]
            inventory.sort((a1, a2) -> a1.getWeight().compareTo(a2.getWeight()));
            System.out.println(inventory);
            
            // reshuffling things a little
            inventory.set(1, new Apple(10, "red"));
            
            // 4
            // [Apple{color='red', weight=10}, Apple{color='red', weight=20}, Apple{color='green', weight=155}]
            inventory.sort(comparing(Apple::getWeight));
            System.out.println(inventory);       
        }
    
        public static class Apple { 
            private Integer weight = 0;
            private String color = "";
    
            public Apple(Integer weight, String color){ 
                this.weight = weight;
                this.color = color;
            }
    
            public Integer getWeight() { 
                return weight;
            }
    
            public void setWeight(Integer weight) { 
                this.weight = weight;
            }
    
            public String getColor() { 
                return color;
            }
    
            public void setColor(String color) { 
                this.color = color;
            }
    
            public String toString() { 
                return "Apple{" +
                       "color='" + color + '\'' +
                       ", weight=" + weight +
                       '}';
            }
        }
    
        static class AppleComparator implements Comparator<Apple> { 
            public int compare(Apple a1, Apple a2){ 
                return a1.getWeight().compareTo(a2.getWeight());
            }
        }
    }