java集合对象属性排序

ゞ浴缸里的玫瑰 2022-06-01 00:41 357阅读 0赞

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
    	}
    	
    	
    
    	
    	
    	
    	
    
    }