子类覆写 1class Person{2 private String name;3 private int age;4 public Person(String name , int age){5 this.name = name;6 this.age = age;7 }8 @Override9 public String toString(){10 return "name:"+this.name+"age:"+this.age;11 }12}13 14public class duotai{15 public static void main(String args []){4 collapsed lines16 Person per = new Person("dog", 18);17 System.out.println(per); // 默认调用toStirng方法,覆写Object中的toString方法18 }19} 对象的比较 1class Person{2 private String name;3 private int age;4 public Person(String name , int age){5 this.name = name;6 this.age = age;7 }8 public boolean equals(Object obj){9 if(!(obj instanceof Person)){ // 如果不是同类,则直接返回false,不同类无法比较10 return false;11 }12 if(obj == null){ //如果不判断null会报空指针错误13 return false;14 }15 if(this == obj) { // 如果是自己跟自己比,则比较地址15 collapsed lines16 return true;17 }18 19 Person per = (Person) obj;20 return this.name.equals(per.name) && this.age == per.age;21 }22}23 24public class duotai{25 public static void main(String args []){26 Person per1 = new Person("寮犱笁", 18);27 Person per2 = new Person("寮犱笁", 18);28 System.out.println(per1.equals(per2)); // true29 }30}