java中Consumer接口的使用教程详解

package java.util.function;

import java.util.Objects;

@FunctionalInterface
public interface Consumer<T> {

    /**
     * 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<T> andThen(Consumer<? super T> after) {
        Objects.requireNonNull(after);
        return (T t) -> { accept(t); after.accept(t); };
    }
}

import java.util.function.Consumer;

public class ConsumerExample {

    public static void main(String[] args) {
        // 创建一个Consumer实例
        Consumer<String> myConsumer = s -> System.out.println(s);

        // 使用Consumer的accept方法
        myConsumer.accept("Hello, Consumer!");
    }
}

import java.util.function.Consumer;

public class ConsumerExample {

    public static void main(String[] args) {
        // 创建两个Consumer实例
        Consumer<String> printUpperCase = s -> System.out.println(s.toUpperCase());
        Consumer<String> printLength = s -> System.out.println("Length: " + s.length());

        // 组合两个Consumer
        Consumer<String> combinedConsumer = printUpperCase.andThen(printLength);

        // 使用组合后的Consumer
        combinedConsumer.accept("Hello, Consumer!");
    }
}

import java.util.function.Consumer;

public class ConsumerExample {

    public static void printUpperCase(String s) {
        System.out.println(s.toUpperCase());
    }

    public static void main(String[] args) {
        // 使用静态方法引用创建Consumer实例
        Consumer<String> myConsumer = ConsumerExample::printUpperCase;

        // 使用Consumer的accept方法
        myConsumer.accept("Hello, Consumer!");
    }
}

import java.util.Arrays;
import java.util.List;
import java.util.function.Consumer;

public class ConsumerExample {

    public static void main(String[] args) {
        List<String> words = Arrays.asList("Java", "is", "fun");

        // 使用Consumer的forEach方法遍历集合元素
        Consumer<String> printUpperCase = s -> System.out.println(s.toUpperCase());
        words.forEach(printUpperCase);
    }
}