这里的家伙是我的简单代码,我不知道为什么会出现异常
我只想设定患者年龄,如果小于122岁。
请帮我解决问题。
Patient.java
public class Patient {
int Age;
String Gender;
public int getAge() {
return Age;
}
public void setAge(int age) {
Age = age;
}
public String getGender() {
return Gender;
}
public void setGender(String gender) {
Gender = gender;
}
public Validation v;
public void patient(int Age, String Gender) {
if(v.age(Age, Gender)) {
this.Age = Age;
this.Gender = Gender;
};
}
}
Validation.java
public class Validation {
public boolean age(int Age, String Gender) {
// TODO Auto-generated method stub
if(Age>122) {
System.out.println("age is high");
return false;
}
else
{
return true;
}
}
}
Main.java
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Patient p = new Patient();
p.patient(23, "Male");
System.out.println(+ p.Age + p.Gender);
}
}
错误
Exception in thread "main" java.lang.NullPointerException
at Patient.patient(Patient.java:24)
at Main.main(Main.java:5)
at Patient.patient(Patient.java:24):if(v.age(Age,Gender)) 在Main.main(Main.java:5):p.patient(23," Male");