s-day03--HashSet存储自定义对象

s-day03/src/com/inmind/set02/HashDemo07.java

@@ -33,10 +33,10 @@ public class HashDemo07 {
         String s4 = "重地";
         String s5 = "abc";
         String s6 = new String("abc");
-        System.out.println(s3.hashCode());
-        System.out.println(s4.hashCode());
-        System.out.println(s5.hashCode());
-        System.out.println(s6.hashCode());
+        System.out.println(s3.hashCode());//1179395
+        System.out.println(s4.hashCode());//1179395
+        System.out.println(s5.hashCode());//96354
+        System.out.println(s6.hashCode());//96354
 
         HashSet<String> sets = new HashSet<>();
         sets.add(s6);

s-day03/src/com/inmind/set02/HashSetDemo08.java

@@ -0,0 +1,27 @@
+package com.inmind.set02;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/*
+HashSet存储自定义对象
+注意：我们保存数据时，先判断哈希值，如果不一样直接存，如果哈希值相同，还要使用equals方法判断内容
+是否相同，如果相同，就不存，不同则保存，所以必须重写hashCode和equals
+ */
+public class HashSetDemo08 {
+    public static void main(String[] args) {
+        Student s1 = new Student("刘备1", 20);
+        Student s2 = new Student("刘备2", 19);
+        Student s3 = new Student("刘备3", 21);
+        Student s4 = new Student("刘备3", 21);
+        Student s5 = new Student("刘备3", 21);
+        HashSet<Student> sets = new HashSet<>();
+        sets.add(s3);
+        sets.add(s2);
+        sets.add(s1);
+        sets.add(s4);
+        sets.add(s5);
+        System.out.println(sets);
+
+    }
+}

s-day03/src/com/inmind/set02/Student.java

@@ -11,6 +11,14 @@ public class Student {
         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;