Java 8 四大内置函数接口使用示例

2018-01-11

Consumer 接口

1
2
3

public interface Consumer<T> {
    void accept(T t);
}

1
2
3

public void happy(double money, Consumer<Double> consumer) {
		consumer.accept(money);
}

1	happy(1000, money -> System.out.println("吃喝玩乐"));

1	happy(10000, money -> System.out.println("旅游"));

Supplier 接口

1
2
3

public interface Supplier<T> {
    T get();
}

public List<Integer> getNumList(int num, Supplier<Integer> supplier) {
	List<Integer> list = new ArrayList<>();
	
	for(int i = 0; i < num; i++) {
		Integer n = supplier.get();
		list.add(n);
	}
	
	return list;
}

1	getNumList(10, () -> (int)(Math.random() * 100))

Function 接口

1
2
3

public interface Function<T, R> {
    R apply(T t);
}

1
2
3

public String strHandler(String str, Function<String, String> function) {
		return function.apply(str);
}

1	strHandler(" Lambda ", str -> str.trim().toUpperCase())

Predicate 接口

1
2
3

public interface Predicate<T> {
    boolean test(T t);
}

public List<String> filterStr(List<String> list, Predicate<String> predicate) {
	List<String> strList = new ArrayList<>();
	
	for(String str : list) {
		if(predicate.test(str)) {
			strList.add(str);
		}
	}
	
	return strList;
}

1 2	List<String> strings = Arrays.asList("Hello", "Lambda", "Function", "Java"); filterStr(strings, str -> str.length() > 5);

代码可参考lxmuse-jdk8-new-feature-lambda-03