TreeSet 添加Student实体类数据利用外部比较器排序

蔚落 2024-03-16 13:20 34阅读 0赞

Student实体类如下所示：

package com.test.Test10;
    
    
    import java.util.Comparator;
    
    public class StudentWaiBuCompare{
        private int age;
        private String name;
    
        public int getAge() {
            return age;
        }
    
        public void setAge(int age) {
            this.age = age;
        }
    
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public StudentWaiBuCompare(int age, String name) {
            this.age = age;
            this.name = name;
        }
    
        @Override
        public String toString() {
            return "Student{" +
                    "age=" + age +
                    ", name='" + name + '\'' +
                    '}';
        }
    
    
    }
    //外部比较器定义
    class BiJiao implements Comparator<StudentWaiBuCompare> {
    
        @Override
        public int compare(StudentWaiBuCompare o1, StudentWaiBuCompare o2) {
            //return 0;
            return o1.getName().compareTo(o2.getName());
        }
    }
    
    测试类如下所示：

package com.test.Test10;
    
    import java.util.Comparator;
    import java.util.TreeSet;
    
    public class Test03WaiBuCompare {
        public static void main(String[] args) {
            //创建一个TreeSet
            //利用外部比较器，必须自己指定
            Comparator<StudentWaiBuCompare> com = new BiJiao();
            TreeSet<StudentWaiBuCompare> ts = new TreeSet<>(com); //一旦指定外部比较器，那么就会按照外部比较器来比较
            ts.add(new StudentWaiBuCompare(10,"elili"));
            ts.add(new StudentWaiBuCompare(8,"blili"));
            ts.add(new StudentWaiBuCompare(4,"alili"));
            ts.add(new StudentWaiBuCompare(9,"clili"));
            ts.add(new StudentWaiBuCompare(10,"elili"));
            ts.add(new StudentWaiBuCompare(1,"dlili"));
            System.out.println(ts.size()); //放了6个数据，出来了5个，重复的删除了
            System.out.println(ts);        //[Student{age=4, name='alili'}, Student{age=8, name='blili'}, Student{age=9, name='clili'}, Student{age=1, name='dlili'}, Student{age=10, name='elili'}]  按照name值的升序进行排列了
        }
    }