• 直接赋值

public class student {
          
   
    String name;                            // 不能有private
    int age;

    student(){
          
   }                           // 不可缺少
    student(String name,int age){
          
   
        this.name =name;                 //  可有可无
        this.age = age;
    }
                                         // 无get（）set（）
    public void show() {
          
   
        System.out.println("学生爱学习");
    }
}

• 利用set()赋值，get()接收

public class Teacher {
          
   
    private String name;                   //  private可有可无
     private int age;

    public Teacher(){
          
   }                  // 必有空参，不可缺少
    public Teacher(String name,int age){
          
   
        this.name = name;                //  可有可无
        this.age = age;
    }
                                        //  用set赋值 必有get（）set（）
    public String getName() {
          
   
        return name;
    }
    public void setName(String name) {
          
   
        this.name = name;
    }
    public int getAge() {
          
   
        return age;
    }
    public void setAge(int age) {
          
   
        this.age = age;
    }
    public void show(){
          
   
        System.out.println("老师爱讲课");
    }
}

• 构造函数赋值

public class xiaozhang {
          
   
    private String name;    // 可有可无
    private int age;

    public xiaozhang() {
          
    }                       // 必有空参，不可缺少
    public xiaozhang(String name, int age) {
          
   
        this.name = name;                        // 必有this.变量
        this.age = age;
        System.out.println(name);              // 若无set()get(),则必有输出sout
        System.out.println(age); // 若有set get，则test中必有System.out.println(xz.getName());
        System.out.println("校长爱转圈");
    }
}
   /* public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;*/

• 测试类test

public class practice {
          
   
    public static void main(String[] args) {
          
   
        // 直接赋值,不能有private
        student stu = new student();
        stu.name = "小明";
        stu.age = 15;
        System.out.println(stu.name);
        System.out.println(stu.age);
        stu.show();                              // 对象名调用函数
        System.out.println("————————");
        //用set() get()赋值
        Teacher t = new Teacher();
        t.setName("李老师");
        t.setAge(45);
        System.out.println(t.getName());        // 用set赋值用get接收
        System.out.println(t.getAge());
        t.show();
        System.out.println("————————");
        //用构造函数赋值
        xiaozhang xz = new xiaozhang("张校长",60);
                     //System.out.println(xz.getName());
                     //System.out.println(xz.getAge());