Question

我有一个带有created Date属性的Contact类。我试图做以下事情：

    Contact received = gson.fromJson(contactJson, Contact.class);

但是我得到了例外：

 com.google.gson.JsonSyntaxException: 1433444958703
at com.google.gson.internal.bind.DateTypeAdapter.deserializeToDate(DateTypeAdapter.java:81)
at com.google.gson.internal.bind.DateTypeAdapter.read(DateTypeAdapter.java:66)

已经发布了类似的解决方案： "Unparseable date: 1302828677828" trying to deserialize with Gson a millisecond-format date received from server

然而它对我不起作用（不会编译）。

Gson版本2.3.1

思想？

TIA， - Ole

Answer 1

在这里找到一个类似的解决方案（Gson: JsonSyntaxException on date），并稍微调整一下：

@implementation RDView

- (id)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        _nodes = [NSMutableArray new];
        for (int i = 0; i<10; i++) {
            NodeView *aNode = [NodeView new];
            CGFloat hue = arc4random_uniform(1000)/1000.0;
            aNode.backgroundColor = [UIColor colorWithHue:hue saturation:1 brightness:1 alpha:.7];
            CGFloat xVal = arc4random_uniform(300);
            CGFloat yVal = arc4random_uniform(400) + 50;
            aNode.frame = CGRectMake(xVal, yVal, 20, 20);
            [self addSubview:aNode];
            UIPanGestureRecognizer *panner = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
            [aNode addGestureRecognizer:panner];
            [_nodes addObject:aNode];
        }
    }
    return self;
}


-(void)awakeFromNib {
    for (NodeView *aNode in self.nodes) {
        [aNode addObserver:self forKeyPath:@"center" options:NSKeyValueObservingOptionNew context:nil];
    }
}


-(void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if ([keyPath isEqualToString:@"center"] ) [self setNeedsDisplay];
}


- (void)drawRect:(CGRect)rect {
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:[self.nodes[0] center]];
    for (int i = 1; i<self.nodes.count; i++) {
        CGFloat dashes[] = {0, path.lineWidth * 2};

        [path setLineDash:dashes count:2 phase:0];
        path.lineCapStyle = kCGLineCapRound;
        [path addLineToPoint:[self.nodes[i] center]];
    }
    [path closePath];
    [path stroke];
}




- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer {
    CGPoint translation = [recognizer translationInView:self];
    recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y);
    [recognizer setTranslation:CGPointMake(0, 0) inView:self];
}

这很有效。如果这是GSON中的默认值，那将会很棒。）。

Answer 2

您可以编写一个简单的Type Adapter并使用GsonBuilder实例注册它，或者在Contact类本身中使用@JsonAdapter注释。请注意，您应该将日期序列化为长字符串，因为long不是有效的JSON类型，可能会被修剪为int（在大多数日期肯定会失败）。

以下是适配器的外观：

public class LongDateTypeAdapter extends TypeAdapter<Date> {
  @Override public void write(JsonWriter out, Date value) throws IOException {
    if (value == null) {
      out.nullValue();
    } else {
      out.value(String.valueOf(value.getTime()));
    }
  }
  @Override public Date read(JsonReader in) throws IOException {
    switch (in.peek()) {
    case NULL: return null;
    case STRING: 
      try {
        return new Date(Long.parseLong(in.nextString()));
      } catch (NumberFormatException e) {
        throw new JsonSyntaxException(e);
      }
    default: throw new JsonSyntaxException("invalid date" + in.getPath());
    }
  }
}

您可以在以下位置查看源代码： https://github.com/google-gson/typeadapters/blob/master/common/src/main/java/LongDateTypeAdapter.java

以下是说明如何使用它的测试： https://github.com/google-gson/typeadapters/blob/master/common/src/test/java/LongDateTypeAdapterTest.java

转换日期时的GSON DateTypeException类型以毫秒为单位

2 个答案: