这篇文章主要讲解了Java8 Supplier接口和Consumer接口的用法，内容清晰明了，对此有兴趣的小伙伴可以学习一下，相信大家阅读完之后会有帮助。
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Supplier接口
package java.util.function; /** * Represents a supplier of results. * *There is no requirement that a new or distinct result be returned each * time the supplier is invoked. * *
This is a functional interface * whose functional method is {@link #get()}. * * @param
the type of results supplied by this supplier * * @since 1.8 */ @FunctionalInterface public interface Supplier { /** * Gets a result. * * @return a result */ T get(); }
supplier接口只有一个抽象方法get(),通过get方法产生一个T类型实例。
实例：
package me.yanand;
import java.util.function.Supplier;
public class TestSupplier {
public static void main(String[] args) {
Supplier appleSupplier = Apple::new;
System.out.println("--------");
appleSupplier.get();
}
}
class Apple{
public Apple() {
System.out.println("创建实例");
}
} Consumer接口
package java.util.function;
import java.util.Objects;
/**
* Represents an operation that accepts a single input argument and returns no
* result. Unlike most other functional interfaces, {@code Consumer} is expected
* to operate via side-effects.
*
* This is a functional interface
* whose functional method is {@link #accept(Object)}.
*
* @param the type of the input to the operation
*
* @since 1.8
*/
@FunctionalInterface
public interface Consumer {
/**
* Performs this operation on the given argument.
*
* @param t the input argument
*/
void accept(T t);
/**
* Returns a composed {@code Consumer} that performs, in sequence, this
* operation followed by the {@code after} operation. If performing either
* operation throws an exception, it is relayed to the caller of the
* composed operation. If performing this operation throws an exception,
* the {@code after} operation will not be performed.
*
* @param after the operation to perform after this operation
* @return a composed {@code Consumer} that performs in sequence this
* operation followed by the {@code after} operation
* @throws NullPointerException if {@code after} is null
*/
default Consumer andThen(Consumer<? super T> after) {
Objects.requireNonNull(after);
return (T t) -> { accept(t); after.accept(t); };
}
}
一个抽象方法accept(T t)定义了要执行的具体操作；注意看andThen方法，接收Consumer<? super T>类型参数，返回一个lambda表达式，此表达式定义了新的执行过程，先执行当前Consumer实例的accept方法，再执行入参传进来的Consumer实例的accept方法，这两个accept方法接收都是相同的入参t。
实例：
package me.yanand;
import java.util.function.Consumer;
public class TestConsumer {
public static void main(String[] args) {
Consumer consumer = (t) -> {
System.out.println(t*3);
};
Consumer consumerAfter = (s) -> {
System.out.println("之后执行："+s);
};
consumer.andThen(consumerAfter).accept(5);
}
} 看完上述内容，是不是对Java8 Supplier接口和Consumer接口的用法有进一步的了解，如果还想学习更多内容，欢迎关注创新互联行业资讯频道。
