Java 中的可变对象主要包括以下几类

原创已于 2025-01-21 17:35:12 修改 · 226 阅读

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#java #开发语言

于 2025-01-21 17:20:57 首次发布

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一、分类

字符串构建器（StringBuilder, StringBuffer）。
集合框架（如 ArrayList, HashMap, HashSet 等）。
数组。
日期和时间类（如 java.util.Date 或 Joda-Time 的 MutableDateTime）。
自定义类，如果它们提供修改内部状态的方法。

二、自定义类可变解释

Student

public class Student {
    private String name;
    private String age;

    public Student(String name, String age) {
        this.name = name;
        this.age = age;
    }

    public Student() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age='" + age + '\'' +
                '}';
    }
}

Teacher

public class Teacher {
    private String name;
    private String age;
     Student students;

    public Teacher() {
    }

    public Teacher(String name, String age, Student students) {
        this.name = name;
        this.age = age;
        this.students = students;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public Student getStudents() {
        return students;
    }

    public void setStudents(Student students) {
        this.students = students;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "name='" + name + '\'' +
                ", age='" + age + '\'' +
                ", students=" + students +
                '}';
    }
}

测试类：test02Test

public class test02Test {
    Teacher liTeacher;

    @Test
    public void testAlist() {

        Student a = new Student("十二", "12");
        Student b = new Student("十三", "13");
//        Teacher liTeacher = new Teacher("李老师", "30", a);
        Teacher chenTeacher = new Teacher("陈老师", "32", b);
        this.liTeacher=chenTeacher;
        System.out.println("一次"+this.liTeacher);
        chenTeacher.students=a;
        System.out.println("二次"+this.liTeacher);


    }
}

测试类解释：

对象赋值后，两个对象指向同一地址，chenTeacher修改内容后，liTeacher的内容也发生改变