四大函数式接口-Predicate和consumer和supplier

package java.util.function;
import java.util.Objects;
/**
 * Represents a predicate (boolean-valued function) of one argument.
 *
 * <p>This is a <a href="package-summary.html">functional interface</a>
 * whose functional method is {@link #test(Object)}.
 *
 * @param <T> the type of the input to the predicate
 *
 * @since 1.8
 */
@FunctionalInterface
public interface Predicate<T> {
    boolean test(T t);
}

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.
 *
 * <p>This is a <a href="package-summary.html">functional interface</a>
 * whose functional method is {@link #accept(Object)}.
 *
 * @param <T> the type of the input to the operation
 *
 * @since 1.8
 */
@FunctionalInterface
public interface Consumer<T> {
/**
     * Performs this operation on the given argument.
     *
     * @param t the input argument
     */
    void accept(T t);
}

package com.wyh.function;
import java.util.function.Consumer;
/**
 * @program: JUC
 * @description: consumer消费型接口和supplier供给型接口
 * @author: 魏一鹤
 * @createDate: 2022-03-06 15:46
 **/
/**
 * Consumer函数式接口只有一个输入参数没有返回值
 *
 * consumer消费型接口和supplier供给型接口是互相对应的
**/
public class demo03 {
public static void main(String[] args){
        Consumer<String> consumer = new Consumer<String>() {
            @Override
public void accept(String o) {
            //打印字符串
                System.out.println(o);
            }
        };
        //调用方法 打印字符串
        consumer.accept("wyh"); //wyh
    }
}

//lambda表达式简化代码
Consumer<String> consumer =(str)->{ System.out.println(str); };
consumer.accept("wyh"); //wyh

@FunctionalInterface
public interface Supplier<T> {
/**
     * Gets a result.
     *
     * @return a result
     */
    T get();
}

package com.wyh.function;
/**
 * @program: JUC
 * @description: consumer消费型接口和supplier供给型接口
 * @author: 魏一鹤
 * @createDate: 2022-03-06 15:58
 **/
import java.util.function.Supplier;
/**
 * supplier供给型接口 没有参数 只有返回值 和consumer消费型接口是相反的
 *
 **/
public class demo04 {
public static void main(String[] args){
        Supplier<Integer> supplier= new Supplier<Integer>() {
            @Override
public Integer get() {
//返回1024
                return 1024;
            }
        };
//打印输出 supplier的get方法返回值
        System.out.println(supplier.get()); //1024
    }
}