java笔记--day11--类object之toString()

1 Object类的所有方法：

public int hashCode()

public final Class getClass()

public String toString()

public boolean equals(Object obj)

protected void finalize()

protected Object clone()

本章节讲述toString()

2 public String toString()

2.1 在没有对其toString()方法进行重写之前

public class StudentDemo {
public static void main(String[] args) {
Student s = new Student();
System.out.println(s.getClass());// class xsh_itcast_02.Student
System.out.println(s.getClass().getName());// xsh_itcast_02.Student

System.out.println("--------------");
System.out.println(s.toString());// xsh_itcast_02.Student@8327473
}
}

2.2 对toString()方法进行重写之后

默认的重写是把该类的所有成员变量值返回。

public class StudentDemo {
public static void main(String[] args) {
Student s = new Student();
System.out.println(s.getClass());// class xsh_itcast_02.Student
System.out.println(s.getClass().getName());// xsh_itcast_02.Student

System.out.println("--------------");
System.out.println(s.toString());// Student [name=null, age=0]
}
}

2.3 注意：直接输出一个对象的名称，就是输出该对象的toString()方法

public class StudentDemo {
public static void main(String[] args) {
Student s = new Student();
System.out.println(s.toString());// Student [name=null, age=0]
System.out.println("--------------");
System.out.println(s);// Student [name=null, age=0]
}
}