Java集合List排序

痛定思痛。 2023-05-31 03:23 33阅读 0赞

# 1、基本数据类型排序 #

1、创建测试类（TestListSort1.java）

package com.jeff;
    
    import java.util.Arrays;
    import java.util.Collections;
    import java.util.List;
    
    public class TestListSort1 { 
    
    	public static void main(String[] args) { 
    		List<Integer> list = Arrays.asList(5, 10, 8, 22, 3, 9);
    		System.out.println("list排序前：");
    		System.out.println(list);
    		Collections.sort(list);
    		System.out.println("list排序后：");
    		System.out.println(list);
    	}
    
    }

2、控制台输出结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70]

# 2、对象类型排序（按年龄正序） #

1、创建测试类（TestListSort2.java）

package com.jeff;
    
    import java.text.SimpleDateFormat;
    import java.util.ArrayList;
    import java.util.Date;
    import java.util.List;
    
    public class TestListSort2 { 
    
    	public static void main(String[] args) throws Exception { 
    		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    		User u1 = new User("刘一", 18, sdf.parse("2019-10-16"));
    		User u2 = new User("陈二", 36, sdf.parse("2018-09-21"));
    		User u3 = new User("张三", 23, sdf.parse("2019-02-09"));
    		User u4 = new User("李四", 10, sdf.parse("2017-06-11"));
    		User u5 = new User("王五", 26, sdf.parse("2019-03-09"));
    		User u6 = new User("赵六", 12, sdf.parse("2019-10-13"));
    		List<User> list = new ArrayList<User>();
    		list.add(u1);
    		list.add(u2);
    		list.add(u3);
    		list.add(u4);
    		list.add(u5);
    		list.add(u6);
    		System.out.println("list排序前：");
    		list.forEach(System.out::println);
    		list.sort((m1, m2) -> { 
    			return m1.getAge() - m2.getAge();
    		});
    		System.out.println("list排序后：");
    		list.forEach(System.out::println);
    	}
    
    }
    
    class User { 
    
    	private String name;
    	private Integer age;
    	private Date birthday;
    
    	public User(String name, Integer age, Date birthday) { 
    		super();
    		this.name = name;
    		this.age = age;
    		this.birthday = birthday;
    	}
    
    	public String getName() { 
    		return name;
    	}
    
    	public void setName(String name) { 
    		this.name = name;
    	}
    
    	public Integer getAge() { 
    		return age;
    	}
    
    	public void setAge(Integer age) { 
    		this.age = age;
    	}
    
    	public Date getBirthday() { 
    		return birthday;
    	}
    
    	public void setBirthday(Date birthday) { 
    		this.birthday = birthday;
    	}
    
    	@Override
    	public String toString() { 
    		return "User [name=" + name + ", age=" + age + ", birthday=" + birthday + "]";
    	}
    
    }

2、控制台输出结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70 1]

# 3、对象类型排序（按时间正序） #

1、创建测试类（TestListSort3.java）

package com.jeff;
    
    import java.text.SimpleDateFormat;
    import java.util.ArrayList;
    import java.util.Date;
    import java.util.List;
    
    public class TestListSort3 { 
    
    	public static void main(String[] args) throws Exception { 
    		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    		User u1 = new User("刘一", 18, sdf.parse("2019-10-16"));
    		User u2 = new User("陈二", 36, sdf.parse("2018-09-21"));
    		User u3 = new User("张三", 23, sdf.parse("2019-02-09"));
    		User u4 = new User("李四", 10, sdf.parse("2017-06-11"));
    		User u5 = new User("王五", 26, sdf.parse("2019-03-09"));
    		User u6 = new User("赵六", 12, sdf.parse("2019-10-13"));
    		List<User> list = new ArrayList<User>();
    		list.add(u1);
    		list.add(u2);
    		list.add(u3);
    		list.add(u4);
    		list.add(u5);
    		list.add(u6);
    		System.out.println("list排序前：");
    		list.forEach(System.out::println);
    		list.sort((m1, m2) -> { 
    			if (m1.getBirthday().getTime() > m2.getBirthday().getTime()) { 
    				return 1;
    			} else if (m1.getBirthday().getTime() < m2.getBirthday().getTime()) { 
    				return -1;
    			} else { 
    				return 0;
    			}
    		});
    		System.out.println("list排序后：");
    		list.forEach(System.out::println);
    	}
    
    }
    
    class User { 
    
    	private String name;
    	private Integer age;
    	private Date birthday;
    
    	public User(String name, Integer age, Date birthday) { 
    		super();
    		this.name = name;
    		this.age = age;
    		this.birthday = birthday;
    	}
    
    	public String getName() { 
    		return name;
    	}
    
    	public void setName(String name) { 
    		this.name = name;
    	}
    
    	public Integer getAge() { 
    		return age;
    	}
    
    	public void setAge(Integer age) { 
    		this.age = age;
    	}
    
    	public Date getBirthday() { 
    		return birthday;
    	}
    
    	public void setBirthday(Date birthday) { 
    		this.birthday = birthday;
    	}
    
    	@Override
    	public String toString() { 
    		return "User [name=" + name + ", age=" + age + ", birthday="
    				+ new SimpleDateFormat("yyyy-MM-dd").format(birthday) + "]";
    	}
    
    }

2、控制台输出结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70 2]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70]: /images/20230531/4bdf07535b554a24b65861ad7e3802e7.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70 1]: /images/20230531/fefafa6c343d4c97bafdd504f812678d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70 2]: /images/20230531/ee4e7be23e0d47b8ac732d049a8d0925.png