Java8之lambda表达式基本语法

class Student{
  private String name;
  private Double score;
  public Student(String name, Double score) {
    this.name = name;
    this.score = score;
  }
  public String getName() {
    return name;
  }
  public Double getScore() {
    return score;
  }
  public void setName(String name) {
    this.name = name;
  }
  public void setScore(Double score) {
    this.score = score;
  }
  @Override
  public String toString() {
    return "{"
        + "\"name\":\"" + name + "\""
        + ", \"score\":\"" + score + "\""
        + "}";
  }
}
@Test
public void test1(){
  List<Student> studentList = new ArrayList<Student>(){
    {
      add(new Student("stu1",100.0));
      add(new Student("stu2",97.0));
      add(new Student("stu3",96.0));
      add(new Student("stu4",95.0));
    }
  };
  Collections.sort(studentList, new Comparator<Student>() {
    @Override
    public int compare(Student o1, Student o2) {
      return Double.compare(o1.getScore(),o2.getScore());
    }
  });
  System.out.println(studentList);
}

@FunctionalInterface
public interface Comparator<T> {
  int compare(T o1, T o2);
}

public void test1_(){
    List<Student> studentList = new ArrayList<Student>(){
      {
        add(new Student("stu1",100.0));
        add(new Student("stu2",97.0));
        add(new Student("stu3",96.0));
        add(new Student("stu4",95.0));
      }
    };
    Collections.sort(studentList,(s1,s2)-> Double.compare(s1.getScore(),s2.getScore()));
    System.out.println(studentList);
  }

public void testThread(){
    new Thread(new Runnable() {
      @Override
      public void run() {
        System.out.println("hello, i am thread!");
      }
    }).start();
  }

@FunctionalInterface
public interface Runnable {
  /**
   * When an object implementing interface <code>Runnable</code> is used
   * to create a thread, starting the thread causes the object's
   * <code>run</code> method to be called in that separately executing
   * thread.
   * <p>
   * The general contract of the method <code>run</code> is that it may
   * take any action whatsoever.
   *
   * @see   java.lang.Thread#run()
   */
  public abstract void run();
}

public void testThread_(){
  new Thread(()-> System.out.println("hello, i am thread!")).start();
}

@FunctionalInterface
public interface MyFunctionalInterface {
  public void single(String msg);
}
/**
 * 需要单个参数
 */
public static void testOnePar(MyFunctionalInterface myFunctionalInterface){
  myFunctionalInterface.single("msg");
}
/**
   * 一个参数，可以省略参数的括号
   */
  @Test
  public void testOneParameter(){
    testOnePar(x-> System.out.println(x));
  }

/**
   * 需要单个参数
   */
  public static void testOnePar1(Consumer unaryOperator){
    unaryOperator.accept("msg");
  }