[Java]Object类的toString()方法

Object类是所有类的父类，Object中有一个方法为toString方法，首先看官方文档介绍：

public String toString()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())

Returns:

a string representation of the object.

从官方文档可以看出，toString()方法返回的是“ 类名 + '@' + 类的hashcode的十六进制”，因此，这样的表达方式很少有人能看懂，所用在用的时候就要重写此方法。

程序一：（没有重写toString）

class Person extends Object
{
String name = "lavender";
int age = 21;
}
public class toStringDemo1 {

public static void main(String[] args) {
Person p = new Person();
System.out.println(p);

}

}

程序运行结果为：

Person@327800e9

程序二：（将toString()方法重写）

class Person extends Object
{
String name = "lavender";
int age = 21;

//重写Object类中的toString()方法
public String toString()
{
return "I am " + this.name + ", I am " + age + " years old.";
}
}
public class toStringDemo1 {

public static void main(String[] args) {
Person p = new Person();
System.out.println(p);

}

}

运行结果：

I am lavender, I am 21 years old.