From 5ff73a08ad09392b53d4dfd6c39f2d50e2ef2ab3 Mon Sep 17 00:00:00 2001 From: xuxin <840198532@qq.com> Date: Sun, 19 Jul 2026 15:15:59 +0800 Subject: [PATCH] =?UTF-8?q?day06-=E5=B0=81=E8=A3=85=E7=9A=84=E4=BC=98?= =?UTF-8?q?=E5=8C=96=5F=E6=9E=84=E9=80=A0=E6=96=B9=E6=B3=95?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- day06/src/com/inmind/private02/Demo04.java | 19 +++++++++ day06/src/com/inmind/private02/Student.java | 45 +++++++++++++++++++++ 2 files changed, 64 insertions(+) create mode 100644 day06/src/com/inmind/private02/Demo04.java diff --git a/day06/src/com/inmind/private02/Demo04.java b/day06/src/com/inmind/private02/Demo04.java new file mode 100644 index 0000000..fc6541e --- /dev/null +++ b/day06/src/com/inmind/private02/Demo04.java @@ -0,0 +1,19 @@ +package com.inmind.private02; +/* +构造方法的使用 + */ +public class Demo04 { + public static void main(String[] args) { + //无参构造方法,创建学生对象 + Student s1 = new Student(); + s1.study("python"); + //满参构造方法,创建学生对象 + Student s2 = new Student("张三",18,1); + s2.study("java"); + + //第一天报名只知道学号 + Student s3 = new Student(43); + System.out.println(s3.getId()); + s3.study("C++"); + } +} diff --git a/day06/src/com/inmind/private02/Student.java b/day06/src/com/inmind/private02/Student.java index 7896fa9..730f809 100644 --- a/day06/src/com/inmind/private02/Student.java +++ b/day06/src/com/inmind/private02/Student.java @@ -1,10 +1,55 @@ package com.inmind.private02; +/* +Student s = new Student(); +Student():就是Student类的默认无参构造方法,(编译器主动加的!!!) +普通自定义方法: +方法修饰符 返回值类型 方法名(参数列表){ + return;方法体 +} + +构造方法: +方法修饰符 构造方法名(参数列表){ + java方法体 +} + +注意:当源文件(.java文件),进行编译时,编译器扫描整个类的内容,如果没有发现构造方法,那么它会自动帮你添加一个 +默认无参构造方法,如果你写了构造方法,编译器就不会自动添加默认无参构造方法 + +1.构造方法没有返回值类型 +2.构造方法必须与类名保持一致 +3.构造方法可以重载(重载:2同1不同) + +构造方法的作用:通过new调用构造方法,创建对象,并且对该对象的属性进行赋值 + */ public class Student { private String name; private int age; private int id; + //无参构造方法 + public Student(){ + System.out.println("无参构造方法执行了"); + } + //有参构造方法 + public Student(String name){ + System.out.println("有参构造方法执行了"); + this.name = name; + } + + //有参构造方法 + public Student(int id){ + System.out.println("有参构造方法执行了"); + this.id = id; + } + + //满参构造方法,在创建对象的时候,直接对所有属性赋值 + public Student(String name,int age,int id){ + System.out.println("满参构造方法执行了"); + this.name = name; + this.age = age; + this.id = id; + } //设置年龄