Java8

JDK8自带的函数式接口Function有两个默认方法andThen和compose，它们都返回Function的一个实例，可以用这两个方法把Function接口所代表的的Lambda表达式复合起来。

先看个简单的例子：

1Function<Integer, Integer> f = x -> x + 1;
2Function<Integer, Integer> g = x -> x * 2;
3// andThe用法
4Function<Integer, Integer> h = f.andThen(g);
5// (2+1)*2 = 6
6System.out.println(h.apply(2));
7// (5+1)*2=12
8System.out.println(h.apply(5));
9
10//compose用法
11Function<Integer, Integer> p = f.compose(g);
12//(3*2)+1=7
13System.out.println(p.apply(3));
14//(9*2)+1=19
15System.out.println(p.apply(9));

简单的应用

1package org.burning.sport.javase.lambda.chapter3.function;
2
3public class Letter {
4    public static String addHeader(String text) {
5        return "From ZhejiangHZ " + text;
6    }
7
8    public static String addFooter(String text) {
9        return "Sign YingjieLi " + text;
10    }
11
12    public static String checkSpell(String text) {
13        return text.replace("li", "zhang");
14    }
15}
16
17/**
18 * 实际的应用一下
19 */
20Function<String, String> header = Letter::addHeader;
21Function<String, String> pipeLine = header.andThen(Letter::addFooter).andThen(Letter::checkSpell);
22System.out.println(pipeLine.apply("wangying"));
23
24Function<String, String> pipeLine2 = header.compose(Letter::addFooter);
25System.out.println(pipeLine2.apply("jiahao"));

https://gitee.com/play-happy/base-project

参考：

【1】《Java8实战》