【Java】List中存放若干学生对象（学生有学号，姓名，性别等属性），去除List中重复的元素，并按学号降序输出。

太过爱你忘了你带给我的痛 2022-01-16 01:39 59阅读 0赞

package edu;
    
    import java.util.Objects;
    
    public class Student implements Comparable{
        
        int code;
        String name;
        char sex;
    
        public Student(int code, String name, char sex) {
        
            this.code = code;
            this.name = name;
            this.sex = sex;
        }
    
        public int getCode() {
        
            return code;
        }
    
        public void setCode(int code) {
        
            this.code = code;
        }
    
        public char getSex() {
        
            return sex;
        }
    
        public void setSex(char sex) {
        
            this.sex = sex;
        }
    
        public String getName() {
        
            return name;
        }
    
        public void setName(String name) {
        
            this.name = name;
        }
    
    //    @Override
    //    public int hashCode() {
        
    //        return new Integer(code).hashCode()+name.hashCode()+new Character(sex).hashCode();
    //    }
    
    //    @Override
    //    public boolean equals(Object obj) {
        
    //        if(obj instanceof  Student){
        
    //            Student s=(Student)obj;
    //            if(s.code==this.code&&
    //            s.name.equals(this.name)&&
    //            s.sex==this.sex){
        
    //                return true;
    //            }
    //        }
    //        return false;
    //    }
    
        @Override
        public String toString() {
        
            return "Student{" +
                    "code=" + code +
                    ", name='" + name + '\'' +
                    ", sex=" + sex +
                    '}';
        }
    
        @Override
        public int compareTo(Object o) {
        
            if (o instanceof Student) {
        
                Student s = (Student) o;
                if (this.code > s.code) return -1;
                if (this.code < s.code) return 1;
                return 0;
            }
            throw new RuntimeException("类型不匹配无法比较大小");
        }
    
    
    
        @Override
        public boolean equals(Object o) {
        
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            Student student = (Student) o;
            return code == student.code &&
                    sex == student.sex &&
                    Objects.equals(name, student.name);
        }
    
        @Override
        public int hashCode() {
        
            return Objects.hash(code, name, sex);
        }
    }

package edu;
    
    import java.util.*;
    
    public class Test111 {
        
        public static void main(String[] args) {
        
           List list =new ArrayList();
            list.add(new Student(1000,"zhansgan",'M'));
            list.add(new Student(1000,"zhansgan",'M'));
        list.add(new Student(1001,"shshsid",'F'));
            list.add(new Student(1002,"shdskdf",'M'));
            list.add(new Student(1003,"dhfjisof",'M'));
            list.add(new Student(1004,"hfujfodo",'M'));
            System.out.println(list.size());
            TreeSet treeSet=new TreeSet(list);
            Iterator iter=treeSet.iterator();
            while (iter.hasNext()){
        
                System.out.println(iter.next());
            }
        }
    }

![在这里插入图片描述][20190613195632929.png]

[20190613195632929.png]: /images/20220115/2f80bedf07554754ac39d616f27e99cf.png