NSMutableArray *items = [NSMutableArray array];
//读取数据
NSData *jsonData = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"multPoints" ofType:@"json"]];
if (jsonData) {
    NSArray *array = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:nil];
    for (NSDictionary *dic in array) {
        @autoreleasepool {
            BMKMultiPointItem *item = [[BMKMultiPointItem alloc] init];
            item.coordinate = CLLocationCoordinate2DMake([dic[@"lat"] floatValue], [dic[@"lng"] floatValue]);
            [items addObject:item];
        }
    }
}
_multiPointOverlay = [BMKMultiPointOverlay multiPointOverlayWithMultiPointItems:items];
/**
 向地图View添加Overlay，需要实现BMKMapViewDelegate的-mapView:viewForOverlay:方法
 来生成标注对应的View
 
 @param overlay 要添加的overlay
 */
[_mapView addOverlay:self.multiPointOverlay];

#pragma mark - BMKMapViewDelegate
/**
 根据overlay生成对应的BMKOverlayView
 
 @param mapView 地图View
 @param overlay 指定的overlay
 @return 生成的覆盖物View
 */
- (BMKOverlayView *)mapView:(BMKMapView *)mapView viewForOverlay:(id<BMKOverlay>)overlay {
    if ([overlay isKindOfClass:[BMKMultiPointOverlay class]]) {
        //初始化一个overlay并返回相应的BMKMultiPointOverlayView的实例
        BMKMultiPointOverlayView *multiPointOverlayView = [[BMKMultiPointOverlayView alloc] initWithMultiPointOverlay:overlay];
        multiPointOverlayView.icon = [UIImage imageNamed:@"multPoints"];
        multiPointOverlayView.anchor = CGPointMake(0.5, 1.0);
        multiPointOverlayView.pointSize = CGSizeMake(32, 32);
  MultipointOverlayView.delegate = self;
        return multiPointOverlayView;
    }
    return nil;
}

//MARK:BMKMapViewDelegate
/**
 根据overlay生成对应的BMKOverlayView
     
 @param mapView 地图View
 @param overlay 指定的overlay
 @return 生成的覆盖物View
 */
- (void)multiPointOverlayView:(BMKMultiPointOverlayView *)overlayView didItemTapped:(BMKMultiPointItem *)item {
    [self.mapView removeAnnotations:self.mapView.annotations];
    [self.mapView addAnnotation:item];
}