使用示例:

使用场景

RewritePeron的isEqual方法重写

完整代码:

//  RewritePerson.h

#import <Foundation/Foundation.h>

@interface RewritePerson : NSObject

@property (nonatomic, copy) NSString *personId;
@property (nonatomic, copy) NSString *name;

@end

//  RewritePerson.m

#import "RewritePerson.h"

@implementation RewritePerson

#pragma mark - Override Methods

- (BOOL)isEqual:(id)object {
  if (self == object) {
    return YES;
  }

  if ([object isKindOfClass:[RewritePerson class]]) {
    RewritePerson *rewritePerson = (RewritePerson *)object;
    return [self isEqualToPerson:rewritePerson];
  }

  return NO;
}

- (BOOL)isEqualToPerson:(RewritePerson *)rewritePerson {
  if (!rewritePerson) {
    return NO;
  }

  BOOL isEqualPersonId = (!self.personId && !rewritePerson.personId) || [self.personId isEqualToString:rewritePerson.personId];
  BOOL isEqualName = (!self.name && !rewritePerson.name) || [self.name isEqualToString:rewritePerson.name];

  return isEqualPersonId && isEqualName;
}

- (NSUInteger)hash {
  return [self.personId hash] ^ [self.name hash];
}

@end

//  ViewController.m

#import "ViewController.h"
#import "RewritePerson.h"
#import "Person.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
  [super viewDidLoad];

  /**********未重写isEqual方法的Person**************/

  Person *person1 = [Person new];
  person1.personId = @"personId1";
  person1.name = @"name1";

  Person *person2 = [Person new];
  person2.personId = @"personId1";
  person2.name = @"name1";

  NSLog(@"person1isEqual person2 ? %@", [person1 isEqual:person2] ? @"是" : @"否");
  //结果为:  person1 isEqual person2 ?  否


  /**********重写isEqual方法的RewritePerson**************/

  RewritePerson *rewritePerson1 = [RewritePerson new];
  rewritePerson1.personId = @"personId1";
  rewritePerson1.name = @"name1";

  RewritePerson *rewritePerson2 = [RewritePerson new];
  rewritePerson2.personId = @"personId1";
  rewritePerson2.name = @"name1";

  NSLog(@"rewritePerson1 isEqual rewritePerson2 ? %@", [rewritePerson2 isEqual:rewritePerson2] ? @"是" : @"否");
  //结果为:  rewritePerson1 isEqual rewritePerson2 ? 是
}

@end