如何在 Java 中的 lambda 表示式中使用 Consumer 和 BiConsumer 介面?
Consumer 介面是一個**預定義的函式式介面**,可在建立**lambda**表示式或**方法**引用時使用。此介面表示一個接受**單個輸入引數**且不返回任何內容的操作。它僅包含一個名為**accept()**的方法。BiConsumer 介面類似於**Consumer 介面,它接受**兩個輸入引數**,且不返回任何內容。
語法
@FunctionalInterface public interface Consumer<T> @FunctionalInterface public interface BiConsumer<T, U>
示例
import java.util.*; import java.util.function.*; public class ConsumerBiConsumerTest { public static void main(String[] args) { Consumer<String> c = (x) -> System.out.println(x.toLowerCase()); // lambda expression c.accept("Raja"); Consumer<Integer> con = (x) -> { // lambda expression System.out.println(x + 10); System.out.println(x - 10); }; con.accept(10); BiConsumer<Strng, String> bc = (x, y) -> { System.out.println(x + y);}; bc.accept("1", "2"); List<Person> plist = Arrays.asList(new Person("RAJA"), new Person("ADITHYA")); acceptAllEmployee(plist, p -> System.out.println(p.name)); acceptAllEmployee(plist, p -> {p.name = "unknown";}); acceptAllEmployee(plist, p -> System.out.println(p.name)); } public static void acceptAllEmployee(List<Person> plist, Consumer<P> con) { for(Person p : plist) { con.accept(p); } } } // Person class class Person { public String name; public Person(String name) { this.name = name; } }
輸出
raja 20 0 12 RAJA ADITHYA unknown unknown
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