java8之lambda表达式（1）-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");
    }