Java函数式接口Supplier接口实例详解

// Supplier接口源码


@FunctionalInterface
public interface Supplier<T> {

  /**
   * Gets a result.
   *
   * @return a result
   */
  T get();
}

import java.util.function.Supplier;

public class Demo01Supplier {
  public static void main(String[] args) {
    String msgA = "Hello ";
    String msgB = "World ";
    System.out.println(
        getString(
            () -> msgA + msgB
        )
    );
  }

  private static String getString(Supplier<String> stringSupplier) {
    return stringSupplier.get();
  }
}

import java.util.function.Supplier;

public class DemoNumberMax {
  public static void main(String[] args) {
    int[] numbers = {100, 200, 300, 400, 500, -600, -700, -800, -900, -1000};
    int numberMax = arrayMax(
        () -> {
          int max = numbers[0];
          for (int number : numbers) {
            if (max < number) {
              max = number;
            }
          }
          return max;
        }
    );
    System.out.println("数组中的最大值为：" + numberMax);
  }

  /**
   * 获取一个泛型参数指定类型的对象数据
   * @param integerSupplier 方法的参数为Supplier，泛型使用Integer
   * @return 指定类型的对象数据
   */
  public static Integer arrayMax(Supplier<Integer> integerSupplier) {
    return integerSupplier.get();
  }
}