java新特性之Stream，演变过程

比眉伴天荒 2023-09-29 13:57 6阅读 0赞

遍历数组1.0

public static void ergodicList(List<Integer> list){
    
            for (int i = 0; i < list.size(); i++) {
    
                System.out.println(list.get(i));
            }
    
    
        }

看一下编译出的字节码

![c7d6bbce1b9447dcb5b476410958d6c2.png][]

遍历List1.5

public static void ergodicList(List<Integer> list){
    
            for (Integer temp : list) {
    
                System.out.println(temp);
            }
    
    
        }

编译结果

![513dd16cd2934edeaa7514ab5f64b682.png][]

遍历List 2.0

public static void ergodicList(List<Integer> list){
    
            Stream<Integer> stream = list.stream();
    
            // 使用consumer接口实现方法
            Consumer<Integer> consumer = new Consumer<Integer>() {
    
                @Override
                public void accept(Integer temp) {
                    System.out.print(temp);
                }
            };
    
            stream.forEach(consumer);
    
    
        }

编译结果

![27e8587358ea4786978690f8f361d0f7.png][]

遍历List 2.5

public static void ergodicList(List<Integer> list){
    
            Stream<Integer> stream = list.stream();
    
            Consumer<Integer> consumer = (num) -> {
                System.out.print(num);
            };
    
    
    
            stream.forEach(consumer);
    
    
        }

编译结果

![784aac40c1874dd7b2af4a244f2234c8.png][]

遍历List 3.0

public static void ergodicList(List<Integer> list){
    
            Stream<Integer> stream = list.stream();
    
            Consumer<Integer> consumer = num -> System.out.print(num);
    
            stream.forEach(consumer);
    
    
        }

编译结果和2.5一样

![9a0a16f9ea9a4ff88dfeb4022620e8b5.png][]

遍历List 3.5

public static void ergodicList(List<Integer> list){
    
            Stream<Integer> stream = list.stream();
    
            stream.forEach(System.out::print);
    
        }

编译结果

![bb378dbea76c499da359001dddd3a63f.png][]

遍历List 4.0

public static void ergodicList(List<Integer> list){
    
            list.stream().forEach(System.out::print);
    
        }

编译结果和3.5一样

![cb99364735724f359ed6732f355c0799.png][]

三重奏

![9d9e75f5d5d047568bdc1e83dc826cbc.png][]

不熟悉之前，先写匿名内部类，再逐步过度到lambda表达式

实在不行，先写匿名内部类，再在内名函数上用alt+enter，替换成lambda

![007c6496b621469483032ccad00637a0.png][]

[c7d6bbce1b9447dcb5b476410958d6c2.png]: https://img-blog.csdnimg.cn/c7d6bbce1b9447dcb5b476410958d6c2.png
[513dd16cd2934edeaa7514ab5f64b682.png]: https://img-blog.csdnimg.cn/513dd16cd2934edeaa7514ab5f64b682.png
[27e8587358ea4786978690f8f361d0f7.png]: https://img-blog.csdnimg.cn/27e8587358ea4786978690f8f361d0f7.png
[784aac40c1874dd7b2af4a244f2234c8.png]: https://img-blog.csdnimg.cn/784aac40c1874dd7b2af4a244f2234c8.png
[9a0a16f9ea9a4ff88dfeb4022620e8b5.png]: https://img-blog.csdnimg.cn/9a0a16f9ea9a4ff88dfeb4022620e8b5.png
[bb378dbea76c499da359001dddd3a63f.png]: https://img-blog.csdnimg.cn/bb378dbea76c499da359001dddd3a63f.png
[cb99364735724f359ed6732f355c0799.png]: https://img-blog.csdnimg.cn/cb99364735724f359ed6732f355c0799.png
[9d9e75f5d5d047568bdc1e83dc826cbc.png]: https://img-blog.csdnimg.cn/9d9e75f5d5d047568bdc1e83dc826cbc.png
[007c6496b621469483032ccad00637a0.png]: https://img-blog.csdnimg.cn/007c6496b621469483032ccad00637a0.png