本文关键词：Java 8， 函数式接口，lambda，BiFunction。
介绍
全路径: java.util.function.BiFunction 。
Java 8 中引入。
源码：
package java.util.function;
import java.util.Objects;
/**
* Represents a function that accepts two arguments and produces a result.
* This is the two-arity specialization of {@link Function}.
*
* <p>This is a <a href="package-summary.html">functional interface</a>
* whose functional method is {@link #apply(Object, Object)}.
*
* @param <T> the type of the first argument to the function
* @param <U> the type of the second argument to the function
* @param <R> the type of the result of the function
*
* @see Function
* @since 1.8
*/
@FunctionalInterface
public interface BiFunction<T, U, R> {
/**
* Applies this function to the given arguments.
*
* @param t the first function argument
* @param u the second function argument
* @return the function result
*/
R apply(T t, U u);
/**
* Returns a composed function that first applies this function to
* its input, and then applies the {@code after} function to the result.
* If evaluation of either function throws an exception, it is relayed to
* the caller of the composed function.
*
* @param <V> the type of output of the {@code after} function, and of the
* composed function
* @param after the function to apply after this function is applied
* @return a composed function that first applies this function and then
* applies the {@code after} function
* @throws NullPointerException if after is null
*/
default <V> BiFunction<T, U, V> andThen(Function<? super R, ? extends V> after) {
Objects.requireNonNull(after);
return (T t, U u) -> after.apply(apply(t, u));
}
}
示例
代码示例1
import java.util.function.BiFunction;
public class Main {
public static void main(String[] args) {
BiFunction<Long, Long, Long> add = (num1, num2) -> {
return num1 + num2;
};
Long result = add.apply(1L, 2L);
System.out.println("执行结果: " + result);
}
}
执行结果：
执行结果: 3