s-day04-TreeSet保存自定义对象

s-day04/src/com/inmind/treeset02/Student.java

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+package com.inmind.treeset02;
+
+import java.util.Objects;
+
+public class Student implements Comparable<Student>{
+    String name;
+    int age;
+
+    public Student(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    @Override
+    public String toString() {
+        return "Student{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Student student = (Student) o;
+        return age == student.age && Objects.equals(name, student.name);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = Objects.hashCode(name);
+        result = 31 * result + age;
+        return result;
+    }
+
+    @Override
+    public int compareTo(Student o) {
+        return this.age - o.age;
+    }
+}

s-day04/src/com/inmind/treeset02/TreeSetDemo09.java

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+package com.inmind.treeset02;
+
+import java.util.Comparator;
+import java.util.TreeSet;
+
+/*
+TreeSet保存自定义对象
+注意：TreeSet会使用元素的自带的自然排序功能Comparable接口
+ */
+public class TreeSetDemo09 {
+    public static void main(String[] args) {
+        //创建一个对学生对象有排序功能的集合
+        TreeSet<Student> treeSet = new TreeSet<>();
+        treeSet.add(new Student("小王1", 18));
+        treeSet.add(new Student("小王2", 17));
+        treeSet.add(new Student("小王3", 20));
+        System.out.println(treeSet);
+        System.out.println("--------------如果自定义对象没有自然排序或者不符合我们的需求，使用比较器------------------");
+        TreeSet<Student> sets = new TreeSet<>(new Comparator<Student>() {
+            @Override
+            public int compare(Student o1, Student o2) {
+                return o2.age - o1.age;
+            }
+        });
+
+        sets.add(new Student("小王1", 18));
+        sets.add(new Student("小王2", 17));
+        sets.add(new Student("小王3", 20));
+        System.out.println(sets);
+    }
+}