Java 8 的 Consumer、Supplier、Predicate和Function

package com.learn.tang;

import java.util.ArrayList;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.stream.Stream;

class Student {
	private String name;
	private int age;
	private String type;

	public Student(String name, int age) {
		this.name = name;
		this.age = age;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public String getType() {
		return type;
	}

	public void setType(String type) {
		this.type = type;
	}

	@Override
	public String toString() {
		return "Student [name=" + name + ", age=" + age + ", type=" + type + "]";
	}

}

/**
 * Consumer、Supplier、Predicate、Function
 * <p>
 * 这几个接口都在 java.util.function包下的，分别是:
 * <ul>
 * <li>Consumer（消费型）</li>
 * <li>supplier（供给型）</li>
 * <li>predicate（谓词型）</li>
 * <li>function（功能性）</li>
 * </ul>
 * Stream相关功能：
 * <ul>
 * <li>forEach</li>
 * <li>sum</li>
 * <li>map</li>
 * <li>mapToInt</li>
 * </ul>
 * </p>
 * 
 * @author tang
 *
 */
public class Test003 {

	public static void updateStudent(Student t, Predicate<Student> p, Consumer<Student> c1, Consumer<Student> c2) {
		if (p.test(t)) {
			c1.accept(t);
		} else {
			c2.accept(t);
		}
	}

	public static void main(String[] args) {
		List<Student> list = new ArrayList<>();
		for (int i = 0; i < 10; ++i) {
			final int ii = i;
			Supplier<Student> sp = () -> {
				return new Student("Join" + Integer.valueOf(ii), 5 + ii);
			};

			Student o = sp.get();
			updateStudent(o, (t) -> t.getAge() >= 10, (t) -> t.setType("person"), (t) -> t.setType("young"));
			list.add(o);
		}

		list.stream().forEach((o) -> System.out.println(o));

		int total = list.stream().mapToInt((t) -> t.getAge()).sum();
		System.out.println("total age=" + total);

		Stream<Student> stream = list.stream();
		stream.forEach((o) -> System.out.println(o));

		list.stream().map((t) -> t.getName()).map(String::toUpperCase).forEach(System.out::println);
		list.stream().mapToInt((t) -> t.getAge()).filter((t) -> t > 10).forEach(System.out::println);

		Supplier<String> a = String::new;
		String s = a.get();
		s = s.concat("hello World!");
		System.out.println(s);
	}

}

参考地址：https://blog.csdn.net/sihai12345/article/details/99374583