s-day01-Objects类的equals方法

2026-07-28 15:58:08 +08:00
parent f7ee9137dd
commit ff406a13d1
2 changed files with 70 additions and 0 deletions
@@ -0,0 +1,33 @@
+package com.inmind.objects02;
+
+import java.util.Objects;
+
+/*
+Objects类的equals方法
+    static boolean equals(Object a, Object b) 返回 true如果参数相等，彼此 false否则。
+
+    Objects类的equals方法的作用:在实现判断2个对象是否相同的基础上,有效地避免空指针异常
+ */
+public class Demo04 {
+    public static void main(String[] args) {
+        Person p1 = new Person("貂蝉", 18);
+        Person p2 = new Person("貂蝉", 18);
+
+        System.out.println(p1);
+        System.out.println(p2);
+        System.out.println(p1.equals(p2));//true
+
+//        p1 = null;
+        /*if (p1 != null) {
+            System.out.println(p1.equals(p2));//空指针异常
+        }*/
+        /*
+        Objects类的equals方法
+        static boolean equals(Object a, Object b) 返回 true如果参数相等，彼此 false否则。
+         */
+        boolean result = Objects.equals(p1, p2);
+        System.out.println(result);//true
+
+        System.out.println("程序结束");
+    }
+}
@@ -0,0 +1,37 @@
+package com.inmind.objects02;
+
+import java.util.Objects;
+
+//直接继承Object类
+public class Person{
+    String name;
+    int age;
+
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    @Override
+    public String toString() {
+        return "Person{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Person person = (Person) o;
+        return age == person.age && Objects.equals(name, person.name);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = Objects.hashCode(name);
+        result = 31 * result + age;
+        return result;
+    }
+}