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class B { private int i; B(int i) { this.i=i; } } public class Ex1 { public static void main(String[] args) { B b1=new B(20); B b2=new B(20); System.out.println(b1==b2);//b1==b2比较是内存地址 } }
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class B { private int i; B(int i) { this.i=i; } public boolean equals(B b2)//覆盖equals方法 { if(this.i==b2.i) return true; else return false; } } public class Ex1 { public static void main(String[] args) { B b1=new B(20); B b2=new B(20); //System.out.println(b1==b2); //b1==b2比较是内存地址 System.out.println(b1.equals(b2)); //b1.equals(b2)默认比较内存地址,需覆盖方法 //equals方法默认object类 } }