JAVA对象排序

2019-11-08 02:09:15

字体：大中小

来源：转载

供稿：网友

背景：排序方法，按照部门Id和薪资排序。方法没有返回值，对参数集合进行排序。排序方式是true：按照部门Id升序薪资升序排序；排序方式是false：按照部门Id升序薪资降序排序实质：根据java中的对象进行排序实现思路：实体类实现Comparator接口，并且在排序的类继承实体类，排序的方法中重写compare方法代码实现：实体类：

package com.wonders;import java.util.Comparator;/** * 职员类 * * @author DELL * */public class Employee implements Comparator<Employee>{ PRivate String name;// 姓名 private Long salary;// 薪资 private int departmentId;// 部门ID public String getName() { return name; } public void setName(String name) { this.name = name; } public Long getSalary() { return salary; } @Override public String toString() { return "Employee [name=" + name + ", salary=" + salary + ", departmentId=" + departmentId + "]"; } public void setSalary(Long salary) { this.salary = salary; } public int getDepartmentId() { return departmentId; } public void setDepartmentId(int departmentId) { this.departmentId = departmentId; } @Override public int compare(Employee o1, Employee o2) { return 0; }}

升序排序类：

package com.wonders;/** * 升序排序 * @author DELL * */public class SortObjectAsc extends Employee{ public int compare(Employee o1,Employee o2){ if (o1.getDepartmentId() > o2.getDepartmentId()) { return 1; }else if (o1.getDepartmentId() < o2.getDepartmentId()) { return -1; }else { return 0; } }}

降序排序类：

package com.wonders;/** * 降序排序 * @author DELL * */public class SortObjectDesc extends Employee{ public int compare(Employee o1,Employee o2){ if (o1.getDepartmentId() < o2.getDepartmentId()) { return 1; }else if (o1.getDepartmentId() > o2.getDepartmentId()) { return -1; }else { return 0; } }}

公用方法：

/** * 根据boolean值来对员工信息进行升降排序 * @param list * @param flag ture按照id升序，false按照id降序 * @return */ public static List<Employee> sortMember(List<Employee> list,boolean flag){ if (flag == true) { Collections.sort(list, new SortObjectAsc()); }else if (flag == false) { Collections.sort(list, new SortObjectDesc()); } return list; }

测试类中相关代码：

List<Employee> employeesList = new ArrayList<Employee>(); Employee e1 = new Employee(); e1.setName("zhangsan1"); e1.setSalary(6000L); e1.setDepartmentId(1); employeesList.add(e1); Employee e2 = new Employee(); e2.setName("zhangsan2"); e2.setSalary(7000L); e2.setDepartmentId(2); employeesList.add(e2); Employee e3 = new Employee(); e3.setName("zhangsan3"); e3.setSalary(8000L); e3.setDepartmentId(3); employeesList.add(e3); Employee e11 = new Employee(); e11.setName("zhangsan1"); e11.setSalary(7000L); e11.setDepartmentId(1); employeesList.add(e11); Employee e22 = new Employee(); e22.setName("zhangsan2"); e22.setSalary(8000L); e22.setDepartmentId(2); employeesList.add(e22); Employee e33 = new Employee(); e33.setName("zhangsan3"); e33.setSalary(9000L); e33.setDepartmentId(3); employeesList.add(e33); System.out.println(DateUtils.sortMember(employeesList, true)); System.out.println(DateUtils.sortMember(employeesList, false));

上一篇：Java IO字节输入流常见类进行分析（一）

下一篇：java 基础知识学习指南