一切福田，不離方寸，從心而覓，感無不通。

Java8 使用 stream().filter()过滤List对象（查找符合条件的对象集合）

内容简介

本文主要说明在Java8及以上版本中，使用stream().filter()来过滤一个List对象，查找符合条件的对象集合。

List对象类（StudentInfo）

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
public class StudentInfo implements Comparable<StudentInfo> {
 
    //名称
    private String name;
 
    //性别 true男 false女
    private Boolean gender;
 
    //年龄
    private Integer age;
 
    //身高
    private Double height;
 
    //出生日期
    private LocalDate birthday;
 
    public StudentInfo(String name, Boolean gender, Integer age, Double height, LocalDate birthday){
        this.name = name;
        this.gender = gender;
        this.age = age;
        this.height = height;
        this.birthday = birthday;
    }
 
    public String toString(){
        String info = String.format("%s\t\t%s\t\t%s\t\t\t%s\t\t%s",this.name,this.gender.toString(),this.age.toString(),this.height.toString(),birthday.toString());
        return info;
    }
 
    public static void printStudents(List<StudentInfo> studentInfos){
        System.out.println("[姓名]\t\t[性别]\t\t[年龄]\t\t[身高]\t\t[生日]");
        System.out.println("----------------------------------------------------------");
        studentInfos.forEach(s->System.out.println(s.toString()));
        System.out.println(" ");
    }
 
    @Override
    public int compareTo(StudentInfo ob) {
        return this.age.compareTo(ob.getAge());
        //return 1;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public Boolean getGender() {
        return gender;
    }
 
    public void setGender(Boolean gender) {
        this.gender = gender;
    }
 
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
 
    public Double getHeight() {
        return height;
    }
 
    public void setHeight(Double height) {
        this.height = height;
    }
 
    public LocalDate getBirthday() {
        return birthday;
    }
 
    public void setBirthday(LocalDate birthday) {
        this.birthday = birthday;
    }
}

 

测试数据

1
2
3
4
5
6
//测试数据，请不要纠结数据的严谨性
List<StudentInfo> studentList = new ArrayList<>();
studentList.add(new StudentInfo("李小明",true,18,1.76,LocalDate.of(2001,3,23)));
studentList.add(new StudentInfo("张小丽",false,18,1.61,LocalDate.of(2001,6,3)));
studentList.add(new StudentInfo("王大朋",true,19,1.82,LocalDate.of(2000,3,11)));
studentList.add(new StudentInfo("陈小跑",false,17,1.67,LocalDate.of(2002,10,18)));

 

输出Students列表

1
2
//输出List
StudentInfo.printStudents(studentList);

输出结果如下图：

 使用filter()过滤List

1
2
3
4
//查找身高在1.8米及以上的男生
List<StudentInfo> boys = studentList.stream().filter(s->s.getGender() && s.getHeight() >= 1.8).collect(Collectors.toList());
//输出查找结果
StudentInfo.printStudents(boys);

结果如下图：

 

from:https://www.cnblogs.com/codecat/p/10912454.html

Copyright © 2024 Longsheng All rights reserved