【lambda】java中的引用

@Test
 public void test6(){
      // 获取对象
      PrintStream obj = System.out;
      // 引用对象实例方法
      Consumer<String> consumer1 = obj::println;
      HashMap<String, String> map = new HashMap<>();
      IntSupplier intSupplier = map::size;
  }

@Test
 public void test8() {
      Comparator<Integer> comparator = (a, b) -> {
          return Integer.compare(a, b);
      };
      Comparator<Integer> comparator1 = Integer::compare;
      comparator.compare(1, 2);
  }

// 一个入参
@Test
public void test7() {
   Comparator<String> comparator = String::compareTo;
     Comparator<String> comparator1 = (a, b) -> a.compareTo(b);
     comparator.compare("a", "b");
 }

// 多入参例子
@FunctionalInterface
interface LambdaI<T> {
   T test(T s1,T s2,T s3);
}
class LambdaD{
   LambdaD test(LambdaD s1,LambdaD s2){
       return new LambdaD();
   }
}
class Demo{
   @Test
   public void test9(){
       LambdaI<LambdaD> result = new LambdaI<LambdaD>() {
           @Override
           public LambdaD test(LambdaD s1, LambdaD s2,LambdaD s3) {
               return s1.test(s1, s2);
           }
       };
       LambdaI<LambdaD> result1 = LambdaD::test;
   }
}

@Test
 public void test10(){
     Supplier<HashMap> supplier = HashMap::new;
     Function<String,TestClass> frmo = TestClass::new;
 }
 class TestClass{
     private String name;
     public TestClass(String name) {
         this.name = name;
     }
 }

@Test
 public void test11(){
    Function<Integer,Object[]> function = Object[] :: new;
 }