iOS 根据时间排序

这个是回答这篇文章的问题
http://blog.csdn.net/sinat_30162391/article/details/50916219#comments

创建个date模型

#import <Foundation/Foundation.h>

@interface Date : NSObject

@property (nonatomic, copy) NSString *time;
@end

之后赋值进行排序

    Date *d1 = [[Date alloc] init];
    d1.time = @"2012-12-02";
    Date *d2 = [[Date alloc] init];
    d2.time = @"2412-12-02";
    Date *d3 = [[Date alloc] init];
    d3.time = @"2312-12-02";

    Date *d4 = [[Date alloc] init];
    d4.time = @"2312-12-02";
    Date *d5 = [[Date alloc] init];
    d5.time = @"2812-08-02";
    Date *d6 = [[Date alloc] init];
    d6.time = @"0000-09-02";


    _dataArray = [NSMutableArray array];

    [_dataArray addObject:d1];
    [_dataArray addObject:d2];
    [_dataArray addObject:d3];
    [_dataArray addObject:d4];
    [_dataArray addObject:d5];
    [_dataArray addObject:d6];


    for (int i = 0; i < _dataArray.count; i ++) {
        Date *d = [[Date alloc] init];
        d = _dataArray[i];
        NSLog(@"排序前 == %@", d.time);
    }
    NSLog(@"\n");
    NSSortDescriptor *sorter = [[NSSortDescriptor alloc] initWithKey:@"time" ascending:YES];
    NSMutableArray *sortDescriptors = [[NSMutableArray alloc] initWithObjects:&sorter count:1];
    NSArray *sortArray = [_dataArray sortedArrayUsingDescriptors:sortDescriptors];

    for (int j = 0; j < sortArray.count; j ++) {
        Date *d = [[Date alloc] init];
        d = sortArray[j];
        NSLog(@"排序后 == %@", d.time);
    }

2017-06-10 19:59:35.046 TimeSort[4740:678220] 排序前 == 2012-12-02
2017-06-10 19:59:35.047 TimeSort[4740:678220] 排序前 == 2412-12-02
2017-06-10 19:59:35.047 TimeSort[4740:678220] 排序前 == 2312-12-02
2017-06-10 19:59:35.047 TimeSort[4740:678220] 排序前 == 2312-12-02
2017-06-10 19:59:35.047 TimeSort[4740:678220] 排序前 == 2812-08-02
2017-06-10 19:59:35.047 TimeSort[4740:678220] 排序前 == 0000-09-02
2017-06-10 19:59:35.048 TimeSort[4740:678220] 
2017-06-10 19:59:35.048 TimeSort[4740:678220] 排序后 == 0000-09-02
2017-06-10 19:59:35.048 TimeSort[4740:678220] 排序后 == 2012-12-02
2017-06-10 19:59:35.048 TimeSort[4740:678220] 排序后 == 2312-12-02
2017-06-10 19:59:35.048 TimeSort[4740:678220] 排序后 == 2312-12-02
2017-06-10 19:59:35.048 TimeSort[4740:678220] 排序后 == 2412-12-02
2017-06-10 19:59:35.049 TimeSort[4740:678220] 排序后 == 2812-08-02