forked from fantj2016/java-reader
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathjava8-stream.md
More file actions
124 lines (107 loc) · 3.22 KB
/
Copy pathjava8-stream.md
File metadata and controls
124 lines (107 loc) · 3.22 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
####1. 什么是stream
* stream被定义为泛型接口
* stream接口代表数据流
* stream不是一个数据结构，不直接存储数据
* stream通过管道操作数据
####2. 什么是管道
* 管道包括：
1、数据集：可以是集合、数组等list 、array
2、过滤器filter
3、终端操作，如Stream.forEach方法
####3. 什么是过滤器
* stream的过滤器可以匹配数据源，并返回一个stream对象。
```
Stream<Student> stream = list.stream();
stream = stream.filter(p->p.getSex=='男');
```
#####4. stream实战
1. 创建Student实例
```
package com.fantJ.JAVA_8;
/**
* Created by Fant.J.
* 2017/12/12 21:46
*/
public class Student {
private String name;
private int age;
private String sex;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", sex='" + sex + '\'' +
'}';
}
public Student(String name, String sex, int age) {
this.name = name;
this.age = age;
this.sex = sex;
}
}
```
2. 创建Stream_Collection类
```
package com.fantJ.JAVA_8;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Stream;
/**
* Created by Fant.J.
* 2017/12/12 21:46
*/
public class Stream_Collection {
public static void main(String[] args) {
List<Student> list = init();
//获取stream对象
Stream<Student> stream = list.stream();
//遍历集合
stream.forEach(p-> System.out.println(p.toString()));
}
static List<Student> init(){
List<Student> list = new ArrayList<>();
Student student = new Student("老焦","男",1);
list.add(student);
student = new Student("老王","男",1);
list.add(student);
student = new Student("老赵","女",1);
list.add(student);
return list;
}
}
```
#####5. stream filter实战
稍微修改下Stream_Collection这个类的main方法如下，
```
List<Student> list = init();
//stream过滤器的实例
list.stream()
.filter(p->p.getSex()
.equals("女"))
.forEach(p-> System.out.println(p.toString()));
```
这个过滤器是实现对性别是“女”进行过滤并打印。
######6.进阶
