toString（）
object类是所有Java类的根基类如果类的声明中未使用extends关键字指明其基类，则默认基类为Object类Object类中toString()方法默认返回类名+"@"+其哈希编码
public class T_ToString {
public String toString() {
return "我重写了这个方法";
}
public static void main(String[] args) {
T_ToString rr = new T_ToString();
System.out.println(rr.toString());
}
}
equals
object类中定义有public boolean equals(Object obj)提供定义对象是否”相等“的逻辑Oject的equals方法定义为：x.equals(y)当x和y是同一个对象的引用时返回trueString， Date等类重写了Object的equals方法可以根据需要重写equals方法
public class T_Equals {
int color;
int heigth, weigth;
T_Equals(int color, int height, int weight) {
this.color = color;
this.heigth = height;
this.weigth = weight;
}
public boolean equals(Object obj) {
if(obj == null) return false;
else {
if(obj instanceof T_Equals) {
T_Equals t = (T_Equals)obj;
if( this.color == t.color && this.heigth ==t.heigth && this.weigth == t.weigth) {
return true;
}
}
}
return false;
}
public static void main(String[] args) {
T_Equals ii = new T_Equals (1, 2, 3);
T_Equals qq = new T_Equals (1, 2, 3);
System.out.println(ii == qq);//比较的是两个对象的地址值
System.out.println(ii.equals(qq));
String s1 =new String("猫");
String s2 =new String("猫");
System.out.println(s1.equals(s2));
}
}
