java集合对象属性排序-蒲公英云

java集合对象属性排序

package com.zr.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/**
 * 集合对象属性排序
 * 
 * @author 如
 */
public class SortList {
    public static void main(String[] args) {
        List<User> userList = new ArrayList<User>();
        userList.add(new User("李小龙", "男", 74));
        userList.add(new User("李连杰", "男", 54));
        userList.add(new User("刘亦菲", "女", 29));
        userList.add(new User("杨紫琼", "女", 51));
        System.out.println("排序前：" + userList);
        Collections.sort(userList, new Comparator<User>() {
            /*
             * int compare(User o1, Student o2) 返回一个基本类型的整型
             * 返回负数表示：o1 小于o2，
             * 返回0 表示：o1和o2相等，
             * 返回正数表示：o1大于o2。
             */
            public int compare(User u1, User u2) {
                // 按照年龄进行升序排列
                if (u1.getAge() > u2.getAge()) {
                    return 1;
                }
                if (u1.getAge() == u2.getAge()) {
                    return 0;
                }
                return -1;
            }
        });
        System.out.println("排序后(升序):" + userList);
        Collections.reverse(userList);
        System.out.println("降序:"+userList);
    }
}
package com.zr.List;
public class User {
    private String username;
    private String gender;
    private int age;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "User [username=" + username + ", gender=" + gender + ", age=" + age
                + "]";
    }
    public User(String username, String gender, int age) {
        super();
        this.username = username;
        this.gender = gender;
        this.age = age;
    }
    public User() {
        super();
        // TODO Auto-generated constructor stub
    }
}