Java 8 新特性1-函數式接口
阿新 • • 發佈：2017-05-30
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/* */，
*則表示這個接口是一個函數式接口）
* Conceptually, a functional interface has exactly one abstract
* method. Since [email protected] java.lang.reflect.Method#isDefault()
* default methods} have an implementation, they are not abstract. If
* an interface declares an abstract method overriding one of the
* public methods of [email protected]Java 8 新特性1-函數式接口
(原)
Lambda表達式基本結構：
(param1,param2,param3) -> {代碼塊}
例1：
package com.demo.jdk8;
import java.util.Arrays;
import java.util.List;
import java.util.function.Consumer;
public class Test2 {
public static void main(String[] args) {
for_test();
for_newMethod();
for_lambda();
}
public static void for_test(){
List<Integer> list = Arrays.asList(1,2,3,4,5,6);
for(Integer i : list){
System.out.println(i);
}
}
public static void for_newMethod(){
List<Integer> list = Arrays.asList(1,2,3,4,5,6);
list.forEach(new Consumer<Integer>() {
@Override
public void accept(Integer t) {
System.out.println(t);
}
});
}
public static void for_lambda(){
List<Integer> list = Arrays.asList(1,2,3,4,5,6);
list.forEach(i -> System.out.println(i));
}
}
這三個方法最後執行後的結果都一樣
在for_newMethod方法中，可以看到list新增了一個新方法，forEach，可以叠代裏面的元素，它的參數是一個consumer接口。
Consumer接口在java.util.function包下，該包是java8新引入的工具包，[email protected] /* * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ package java.lang; import java.lang.annotation.*; /** * An informative annotation type used to indicate that an interface * type declaration is intended to be a <i>functional interface</i> as * defined by the Java Language Specification. *這是一個通知性的註解類型，用於去表示某一個接口聲明，它指在規定一個函數式接口， *這個接口由JAVA語言規範去定義的。（[email protected]