List集合根据存储对象的属性字段排序实现

List集合根据存储对象的属性字段排序实现 package com.huixin; import java.util.ArrayList; import java.util.Collections; import java.util.List; /** * ListSort类 * * @author Lance * @date 2017/03/10 */ public class ListSort { public static void main(String[] args) { List<Student> students = new ArrayList<Student>(); students.add(new Student("张三", 24)); students.add(new Student("李四", 23)); students.add(new Student("王五", 25)); System.out.println("before sort:"); for (Student bean : students) { System.out.println("before sort---->age: " + bean.getAge()); } Collections.sort(students); System.out.println("after sort:"); for (Student bean : students) { System.out.println("after sort---->age: " + bean.getAge()); } } } class Student implements Comparable<Student> { private String name; private Integer age; public Student(String name, Integer age) { this.name = name; this.age = age; } /* * s的age小于this的对应字段，则返回负数； * 大于则返回正数； * 建议去了解compareTo背后的真相 */ @Override public int compareTo(Student s) { return s.getAge().compareTo(this.getAge()); } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } } 预期结果 Connected to the target VM, address: '127.0.0.1:3850', transport: 'socket' before sort: before sort---->age: 24 before sort---->age: 23 before sort---->age: 25 after sort: after sort---->age: 25 after sort---->age: 24 after sort---->age: 23

====================================================== 以上是java8之前的用法，java8提供了多种操作方式。博文修改2017.4.7

实体类

@AllArgsConstructor @NoArgsConstructor @Data class Teacher { private String name; private Integer age; } 使用Lambda表达式 List<Teacher> teachers = new ArrayList<Teacher>(); teachers.add(new Teacher("张三", 24)); teachers.add(new Teacher("李四", 23)); teachers.add(new Teacher("王五", 25)); System.out.println("before sort:"); for (Teacher bean : teachers) { System.out.println("before sort---->age: " + bean.getAge()); } //Lambda teachers.sort((s1, s2) -> s1.getAge().compareTo(s2.getAge())); System.out.println("after sort:"); for (Teacher bean : teachers) { System.out.println("after sort---->age: " + bean.getAge()); } 使用Comparator操作器 //Comparator Collections.sort(teachers, Comparator.comparing(Teacher::getAge)); 反序排列 Comparator<Teacher> comparator = (t1, t2) -> t1.getAge().compareTo(t2.getAge()); teachers.sort(comparator.reversed()); 组合排序 //组合排序 teachers.sort(Comparator.comparing(Teacher::getAge).thenComparing(Teacher::getName)); 完整示例代码 package com.huixin.utils.common; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; /** * ListSort类 * * @author Lance * @date 2017/03/10 */ public class ListSortJava8 { public static void main(String[] args) { List<Teacher> teachers = new ArrayList<Teacher>(); teachers.add(new Teacher("张三", 24)); teachers.add(new Teacher("李四", 23)); teachers.add(new Teacher("王五", 25)); teachers.add(new Teacher("钱二", 23)); System.out.println("before sort:"); for (Teacher bean : teachers) { System.out.println("before sort---->age: " + bean.getAge() + "==name：" + bean.getName()); } //Lambda // teachers.sort((t1, t2) -> s1.getAge().compareTo(s2.getAge())); //Comparator // Collections.sort(teachers, Comparator.comparing(Teacher::getAge)); //reversed // Comparator<Teacher> comparator = (t1, t2) -> t1.getAge().compareTo(t2.getAge()); // teachers.sort(comparator.reversed()); //组合排序 teachers.sort(Comparator.comparing(Teacher::getAge).thenComparing(Teacher::getName)); System.out.println("after sort:"); for (Teacher bean : teachers) { System.out.println("after sort---->age: " + bean.getAge() + "==name：" + bean.getName()); } } } @AllArgsConstructor @NoArgsConstructor @Data class Teacher { private String name; private Integer age; }