利用Java8新特性,使用stream().filter()来过滤一个List对象,查找符合条件的对象集合。
1.list里面的学生对象
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;
}
}
2.测试数据
//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)));
3.使用filter()过滤List
//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);
4.输出结果