public void Student(String name,int age,String school){ 多了void
class Person { protected String name; protected int age; // 注意书写规范,setter和getter首字母要小写 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; }}class Student extends Person { public String school; public void setSchool(String school) { this.school = school; } public Student()// 既然写了有参的构造函数,编译器不会再给你提供无参的构造了,如果后面要调用无参的构造,要手动写上 { super(); } public Student(String name, int age, String school)// 构造方法不要加返回类型 { super(); this.school = school; this.name = name; this.age = age; } public void Display() { System.out.println("my name is " + this.name + "my age is " + this.age); } }public class TestExtends { public static void main(String[] args) { Student student = new Student(); student.setSchool("tianhua"); student.setName("john"); student.setAge(22); student.Display();// 这里打印了my name is johnmy age is 22 Student sun = new Student(); sun.setAge(22); System.out.println(sun.getAge());// 这里打印了22 Student student2 = new Student("wangwu", 22, "tianhuaxueyuan"); student2.Display();// 这里打印了my name is wangwumy age is 22 } }
多了void
class Person
{ protected String name;
protected int age; // 注意书写规范,setter和getter首字母要小写
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;
}}class Student extends Person
{ public String school; public void setSchool(String school)
{
this.school = school;
} public Student()// 既然写了有参的构造函数,编译器不会再给你提供无参的构造了,如果后面要调用无参的构造,要手动写上
{
super();
} public Student(String name, int age, String school)// 构造方法不要加返回类型
{
super();
this.school = school;
this.name = name;
this.age = age;
} public void Display()
{
System.out.println("my name is " + this.name + "my age is " + this.age);
}
}public class TestExtends
{
public static void main(String[] args)
{
Student student = new Student();
student.setSchool("tianhua");
student.setName("john");
student.setAge(22);
student.Display();// 这里打印了my name is johnmy age is 22 Student sun = new Student();
sun.setAge(22);
System.out.println(sun.getAge());// 这里打印了22 Student student2 = new Student("wangwu", 22, "tianhuaxueyuan");
student2.Display();// 这里打印了my name is wangwumy age is 22
}
}
我也是刚转学java,想去搞安卓开发,之前一直做c#的
public Student()// 既然写了有参的构造函数,编译器不会再给你提供无参的构造了,如果后面要调用无参的构造,要手动写上
{
super();
}
还有这个这个:
public Student(String name, int age, String school)// 构造方法不要加返回类型
{
super();
的super();呢?求教大神~~谢谢指导~~
{
super();
}这样写是对的,而且必须要加上super();否则会失败,这是java内部语法限制,如果有继承就必须要注意这一点,这个其实可以手动加上,也可以用eclipse等工具自动生成,不过建议以后有继承的话,最好检查一下,没有的就手动加上,以免出错!