JAVA8 stream接口 distinct，sorted，peek，limit，skip

雨点打透心脏的1/2处 2024-04-19 15:39 136阅读 0赞

# JAVA8 stream接口 distinct，sorted，peek，limit，skip #

2018年06月10日 20:25:12 [葵花下的獾][Link 1] 阅读数 4069更多

分类专栏： [ java8 ][java8]

本文链接：[https://blog.csdn.net/qq\_28410283/article/details/80643711][https_blog.csdn.net_qq_28410283_article_details_80643711]

下面，我们来看其他的剩余的一些中间操作，各自的作用，我也通过注释，做了解析，方法定义如下；

1.  `//去重复`
2.  `Stream<T> distinct();`
3.  `//排序`
4.  `Stream<T> sorted();`
5.  `//根据属性排序`
6.  `Stream<T> sorted(Comparator<? super T> comparator);`
7.  `//对对象的进行操作`
8.  `Stream<T> peek(Consumer<? super T> action);`
9.  `//截断--取先maxSize个对象`
10. `Stream<T> limit(long maxSize);`
11. `//截断--忽略前N个对象`
12. `Stream<T> skip(long n);`

下面，我们用一些案例，对这些操作，做一些综合的演示

1.  `package com.taihao;`
2.   
3.  `import java.util.ArrayList;`
4.  `import java.util.Arrays;`
5.  `import java.util.Comparator;`
6.  `import java.util.List;`
7.  `import java.util.stream.Stream;`
8.   
9.  `public class TestJava8 {`
10. `public static List<Emp> list = new ArrayList<>();`
11. `static {`
12. `list.add(new Emp("xiaoHong1", 20, 1000.0));`
13. `list.add(new Emp("xiaoHong2", 25, 2000.0));`
14. `list.add(new Emp("xiaoHong3", 30, 3000.0));`
15. `list.add(new Emp("xiaoHong4", 35, 4000.0));`
16. `list.add(new Emp("xiaoHong5", 38, 5000.0));`
17. `list.add(new Emp("xiaoHong6", 45, 9000.0));`
18. `list.add(new Emp("xiaoHong7", 55, 10000.0));`
19. `list.add(new Emp("xiaoHong8", 42, 15000.0));`
20. `}`
21.  
22. `public static void println(Stream<Emp> stream) {`
23. `stream.forEach(emp -> {`
24. `System.out.println(String.format("名字：%s，年纪：%s，薪水：%s", emp.getName(), emp.getAge(), emp.getSalary()));`
25. `});`
26. `}`
27.  
28. `public static void main(String[] args) {`
29. `// 对数组流，先过滤重复，在排序，再控制台输出 1，2，3`
30. `Arrays.asList(3, 1, 2, 1).stream().distinct().sorted().forEach(str -> {`
31. `System.out.println(str);`
32. `});`
33. `// 对list里的emp对象，取出薪水，并对薪水进行排序，然后输出薪水的内容，map操作，改变了Strenm的泛型对象`
34. `list.stream().map(emp -> emp.getSalary()).sorted().forEach(salary -> {`
35. `System.out.println(salary);`
36. `});`
37. `// 根据emp的属性name，进行排序`
38. `println(list.stream().sorted(Comparator.comparing(Emp::getName)));`
39.  
40. `// 给年纪大于30岁的人，薪水提升1.5倍，并输出结果`
41. `Stream<Emp> stream = list.stream().filter(emp -> {`
42. `return emp.getAge() > 30;`
43. `}).peek(emp -> {`
44. `emp.setSalary(emp.getSalary() * 1.5);`
45. `});`
46. `println(stream);`
47. `// 数字从1开始迭代（无限流），下一个数字，是上个数字+1，忽略前5个 ，并且只取10个数字`
48. `// 原本1-无限，忽略前5个，就是1-5数字，不要，从6开始，截取10个，就是6-15`
49. `Stream.iterate(1, x -> ++x).skip(5).limit(10).forEach(System.out::println);`
50. `}`
51.  
52. `public static class Emp {`
53. `private String name;`
54.  
55. `private Integer age;`
56.  
57. `private Double salary;`
58.  
59. `public Emp(String name, Integer age, Double salary) {`
60. `super();`
61. `this.name = name;`
62. `this.age = age;`
63. `this.salary = salary;`
64. `}`
65.  
66. `public String getName() {`
67. `return name;`
68. `}`
69.  
70. `public void setName(String name) {`
71. `this.name = name;`
72. `}`
73.  
74. `public Integer getAge() {`
75. `return age;`
76. `}`
77.  
78. `public void setAge(Integer age) {`
79. `this.age = age;`
80. `}`
81.  
82. `public Double getSalary() {`
83. `return salary;`
84. `}`
85.  
86. `public void setSalary(Double salary) {`
87. `this.salary = salary;`
88. `}`
89.  
90. `}`
91. `}`

每个例子，也都加了注释，大家看例子，自己get吧

## 1.lambda表达式 ##

[《java8 Lambda表达式简介》][java8 Lambda]

[《java8 lambda表达式，方法的引用以及构造器的引用》][java8 lambda]

### 2.函数式接口 ###

[《java8 函数式接口简介》][java8 1]

[《JAVA8 Function接口以及同类型的特化的接口》][JAVA8 Function]

[《JAVA8 Consumer接口》][JAVA8 Consumer]

[《JAVA8 Supplier接口》][JAVA8 Supplier]

[《JAVA8 UnaryOperator接口》][JAVA8 UnaryOperator]

[《JAVA8 BiConsumer 接口》][JAVA8 BiConsumer]

3.stream接口操作

[《java8 Stream接口简介》][java8 Stream]

[《 java8 Stream-创建流的几种方式》][java8 Stream-]

[《JAVA8 stream接口 中间操作和终端操作》][JAVA8 stream_]

[《JAVA8 Stream接口，map操作，filter操作，flatMap操作》][JAVA8 Stream_map_filter_flatMap]

[《JAVA8 stream接口 distinct，sorted，peek，limit，skip》][https_blog.csdn.net_qq_28410283_article_details_80643711]

[《java8 stream接口 终端操作 forEachOrdered和forEach》][java8 stream_ _ forEachOrdered_forEach]

[《java8 stream接口 终端操作 toArray操作》][java8 stream_ _ toArray]

[《java8 stream接口 终端操作 min，max，findFirst，findAny操作》][java8 stream_ _ min_max_findFirst_findAny]

[《java8 stream接口终端操作 count，anyMatch，allMatch，noneMatch》][java8 stream_ _ min_max_findFirst_findAny]

[《java8 srteam接口终端操作reduce操作》][java8 srteam_reduce]

[《java8 stream接口 终端操作 collect操作》][java8 stream_ _ collect]

4.其他部分

[《java8 Optional静态类简介，以及用法》][java8 Optional]

[Link 1]: https://me.csdn.net/qq_28410283
[java8]: https://blog.csdn.net/qq_28410283/article/category/7718494
[CC 4.0 BY-SA]: http://creativecommons.org/licenses/by-sa/4.0/
[https_blog.csdn.net_qq_28410283_article_details_80643711]: https://blog.csdn.net/qq_28410283/article/details/80643711
[java8 Lambda]: https://blog.csdn.net/qq_28410283/article/details/80961022
[java8 lambda]: https://blog.csdn.net/qq_28410283/article/details/80963351
[java8 1]: https://blog.csdn.net/qq_28410283/article/details/80962325
[JAVA8 Function]: https://blog.csdn.net/qq_28410283/article/details/80615629
[JAVA8 Consumer]: https://blog.csdn.net/qq_28410283/article/details/80618456
[JAVA8 Supplier]: https://blog.csdn.net/qq_28410283/article/details/80625482
[JAVA8 UnaryOperator]: https://blog.csdn.net/qq_28410283/article/details/80634319
[JAVA8 BiConsumer]: https://blog.csdn.net/qq_28410283/article/details/80704487
[java8 Stream]: https://blog.csdn.net/qq_28410283/article/details/80633292
[java8 Stream-]: https://blog.csdn.net/qq_28410283/article/details/80633710
[JAVA8 stream_]: https://blog.csdn.net/qq_28410283/article/details/80634725
[JAVA8 Stream_map_filter_flatMap]: https://blog.csdn.net/qq_28410283/article/details/80642786
[java8 stream_ _ forEachOrdered_forEach]: https://blog.csdn.net/qq_28410283/article/details/80782808
[java8 stream_ _ toArray]: https://blog.csdn.net/qq_28410283/article/details/80783286
[java8 stream_ _ min_max_findFirst_findAny]: https://blog.csdn.net/qq_28410283/article/details/80783946
[java8 srteam_reduce]: https://blog.csdn.net/qq_28410283/article/details/80873910
[java8 stream_ _ collect]: https://blog.csdn.net/qq_28410283/article/details/81052881
[java8 Optional]: https://blog.csdn.net/qq_28410283/article/details/80952768