import java.util.*;
import java.util.stream.Collectors;
public class Test {
public static void main(String[] args) {
List<Student> list = new ArrayList<>();
Student student1 = new Student();student1.setAge("12");student1.setSex(0);
Student student2 = new Student();student2.setAge("13");student2.setSex(2);
Student student3 = new Student();student3.setAge("11");student3.setSex(1);
Student student4 = new Student();student4.setAge("18");student4.setSex(1);
Student student5 = new Student();student5.setAge("18");student5.setSex(0);
Student student6 = new Student();student6.setAge("18");student6.setSex(2);
Student student7 = new Student();student7.setAge("18");student7.setSex(2);
list.add(student1);
list.add(student2);
list.add(student3);
list.add(student4);
list.add(student5);
list.add(student6);
list.add(student7);
List<Demo> demos = new ArrayList<Demo>();
// 原始数据
System.out.println("原始数据 组装list<demo>*******************");
demos = list.stream().map(student -> new Demo(student.getAge(), student.getSex())).collect(Collectors.toList());
demos.forEach(demo -> {
System.out.println("年龄 " + demo.getAge() + " 性别 " + demo.getSex() + ",");
});
// 只取sex为0
System.out.println("只取sex为0****************");
List<Demo> demorm = demos.stream().filter(demo -> demo.getSex() == 0).distinct().collect(Collectors.toList());
demorm.forEach(demo -> {
System.out.println("年龄 " + demo.getAge() + " 性别 " + demo.getSex() + ",");
});
// 筛选年龄大于12岁
System.out.println("筛选年龄大于12岁的*************");
List<Demo> demoFilter = demos.stream().filter(demo -> Integer.valueOf(demo.getAge()) > 12).collect(Collectors.toList());
demoFilter.forEach(demo -> {
System.out.println("年龄 " + demo.getAge() + " 性别 " + demo.getSex() + ",");
});
// 排序
System.out.println("排序******************");
List<Demo> demoSort = demos.stream().sorted((s1, s2) -> s1.getAge().compareTo(s2.getAge())).collect(Collectors.toList());
demoSort.forEach(demo -> {
System.out.println("年龄 " + demo.getAge() + " 性别 " + demo.getSex() + ",");
});
// 倒序
System.out.println("倒序****************");
ArrayList<Demo> demoArray = (ArrayList<Demo>) demos;
Comparator<Demo> comparator = (h1, h2) -> h1.getAge().compareTo(h2.getAge());
demos.sort(comparator.reversed());
//or
demos.sort(Comparator.comparing(Demo::getAge).reversed());
demos.forEach(demo -> {
System.out.println("年龄 " + demo.getAge() + " 性别 " + demo.getSex() + ",");
});
// 多条件正序
System.out.println("多条件排序正序****************");
demoArray.sort(Comparator.comparing(Demo::getSex).thenComparing(Demo::getAge));
demoArray.forEach(demo -> {
System.out.println("年龄 " + demo.getAge() + " 性别 " + demo.getSex() + ",");
});
// 多条件倒序
System.out.println("多条件排序倒序 sex 倒序****************");
demoArray.sort(Comparator.comparing(Demo::getSex).reversed().thenComparing(Demo::getAge));
demoArray.forEach(demo -> {
System.out.println("年龄 " + demo.getAge() + " 性别 " + demo.getSex() + ",");
});
// 按照年龄分组
System.out.println("根据age分组结果为Map****************");
Map<String, List<Demo>> demoOder = demos.stream().collect(Collectors.groupingBy(Demo::getAge));
System.out.println(demoOder);
}
}
class Demo {
private String name;
private Integer sex;
private String age;
public Demo(String age, Integer sex) {
this.age = age;
this.sex = sex;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getSex() {
return sex;
}
public void setSex(Integer sex) {
this.sex = sex;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
}
class Student {
private String age;
private Integer sex;
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
public Integer getSex() {
return sex;
}
public void setSex(Integer sex) {
this.sex = sex;
}
}
