java中的变量有关问题
日期：2014-05-20 浏览次数：20822 次
java中的变量问题
class Person {
String name;
int age;
public void setName(String name) {this.name = name;}
public void setAge(int age) {this.age=age;}
public String getName() {return name;}
public int getAge() {return age;}
public String getInfo() {
return "Name: "+ name + "\n" +"age:"+ age;
}
}
class Student extends Person {
private String school;
public String getSchool() {return school;}
public void setSchool(String school)
{this.school = school;}
public String getInfo() {
return "Name: "+ name +"\n" +"age: "+age
+ "\n" +"school: "+getSchool();
}
}
public class TestOverWrite {
public static void main (String args[]) {
Student student = new Student();
Person person = new Person();
person.setName("none");
person.setAge(1000);
student.setName("john");
student.setAge(18);
student.setSchool("SCH");
System.out.println(person.getInfo());
System.out.println(student.getInfo());
}
}
return "Name: "+ name + "\n" +"age:"+ age;中返回的name,age指的是成员变量还是局部变量？怎么判别的？
------解决方案--------------------
是你理解的成员变量，getInfo方法里面没有任何局部变量的声明，用到的name什么的是类实例的属性
------解决方案--------------------
class Person {
String name;
int age;
public void setName(String name) {this.name = name;}
public void setAge(int age) {this.age=age;}
public String getName() {return name;}
public int getAge() {return age;}
public String getInfo() {
return "Name: "+ name + "\n" +"age:"+ age;
}
}
class Student extends Person {
private String school;
public String getSchool() {return school;}
public void setSchool(String school)
{this.school = school;}
public String getInfo() {
return "Name: "+ name +"\n" +"age: "+age
+ "\n" +"school: "+getSchool();
}
}
public class TestOverWrite {
public static void main (String args[]) {
Student student = new Student();
Person person = new Person();
person.setName("none");
person.setAge(1000);
student.setName("john");
student.setAge(18);
student.setSchool("SCH");
System.out.println(person.getInfo());
System.out.println(student.getInfo());
}
}
return "Name: "+ name + "\n" +"age:"+ age;中返回的name,age指的是成员变量还是局部变量？怎么判别的？
------解决方案--------------------
是你理解的成员变量，getInfo方法里面没有任何局部变量的声明，用到的name什么的是类实例的属性
------解决方案--------------------
- Java code
public String getInfo() {
return "Name: "+ name + "\n" +"age:"+ age; //这里有定义局部变量吗？肯定是成员变量
}
------解决方案--------------------
------解决方案--------------------
- Java code
class Person {
String name;
int age;
public void setName(String name) {this.name = name;}
public void setAge(int age) {this.age=age;}
public String getName() {return name;}
public int getAge() {return age;}
public String getInfo() {
return "Name: "+ name + "\n" +"age:"+ age;
}
}
------解决方案--------------------
成员变量，方法里面没有同名的局部变量，如果有的话要加上this
- Java code
public String getInfo()
{
String name = "XiaoBai";
int age = 12;
if (name != null)
{
return "Name: "+ name + "\n" +"age:"+ age; //这里访问的是局部变量
}
return "Name: "+ this.name + "\n" +"age:"+ this.age; //这里访问的是成员变量
}
------解决方案--------------------
因为是在同一个类体的作用范围内，可以直接引用到name其实相当于this.name
如果放在其他类当中就不行了
------解决方案--------------------
免责声明： 本文仅代表作者个人观点，与爱易网无关。其原创性以及文中陈述文字和内容未经本站证实，对本文以及其中全部或者部分内容、文字的真实性、完整性、及时性本站不作任何保证或承诺，请读者仅作参考，并请自行核实相关内容。
