lambda示例

package function;

import org.junit.jupiter.api.Test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Predicate;

public class Function001 {

    @Test
    public void test001() {
        Comparator<Integer> comparable = (o1, o2) -> Integer.compare( o1, o2 );
        System.out.println( comparable.compare( 10, 12 ) );
        Comparator<Integer> com = Integer::compare;
        System.out.println( com.compare( 15, 13 ) );

    }

    @Test
    public void test002() {

        Consumer<String> consumer = (a) -> System.out.println( a + " hello world" );
        consumer.accept( "boy" );
    }

    @Test
    public void test003() {
        MethodTest( 200, (money) -> System.out.println( "价格是：" + money ) );
    }

    public static void MethodTest(int money, Consumer<Integer> con) {
        con.accept( money );
    }

    @Test
    public void test004() {
        List<String> list = Arrays.asList( "北冰洋","北极","太平洋","印度洋","大西洋" );
//    List<String> filterList =filterList( list,s->s.contains( "洋" ) );
        List<String> filterList = filterList( list, Function001::test );
        System.out.println( filterList );
    }

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

    public static boolean test(String s) {
        return s.contains( "洋" );
    }
}