java 设置 Jackson ObjectMapper 类不对 double 使用科学记数法
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/37722152/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
set Hymanson ObjectMapper class not to use scientific notation for double
提问by Abhij
I am using a library com.fasterxml.Hymanson library for JsonSchema, I am creating creating an IntegerSchema object, when I set range for integer schema using below code:
我正在为 JsonSchema 使用库 com.fasterxml.Hymanson 库，当我使用以下代码为整数模式设置范围时，我正在创建一个 IntegerSchema 对象：
main(){
IntegerSchema intSchema = new IntegerSchema();
// setMaximum accepts Double object
intSchema.setMaximum(new Double(102000000));
// setMaximum accepts Double object
intSchema.setMinimum(new Double(100));
printJsonSchema(intSchema);
}
public void printJsonSchema(JsonSchema schema){
ObjectMapper mapper = new ObjectMapper();
try {
logger.info(mapper.writeValueAsString(schema));
} catch (JsonProcessingException e) {
throw new IllegalStateException(e);
}
}
When I convert IntegerSchema to string using ObjectMapper getting below response:
当我使用 ObjectMapper 将 IntegerSchema 转换为字符串时，得到以下响应：
{"type":"integer","maximum":1.02E8,"minimum":100.0}
maximum and minimum values are getting converted to scientific notation.
最大值和最小值正在转换为科学记数法。
But I need output in non scientific notation as below:
但我需要以非科学记数法输出，如下所示：
{"type":"integer","maximum":102000000,"minimum":100}
I cannot change IntegerSchema class.
我无法更改 IntegerSchema 类。
Please suggest how to get required output without extending IntegerSchema class?
请建议如何在不扩展 IntegerSchema 类的情况下获得所需的输出？
Thanks in advance
提前致谢
回答by pandaadb
this is a java issue somewhat I believe. If you debug your program, your Double will always be displayed scientifically, so what we'll want is to force it into a String. This can be achieved in Java in multiple ways, and you can look it up here:
我相信这是一个java问题。如果您调试程序，您的 Double 将始终科学地显示，因此我们想要的是将其强制为 String。这可以通过多种方式在 Java 中实现，您可以在此处查找：
How to print double value without scientific notation using Java?
In terms of your specific question about Hymanson, I've written up some code for you:
就您关于Hyman逊的具体问题而言，我已经为您编写了一些代码：
public class ObjectMapperTest {
public static void main(String[] args) throws JsonProcessingException {
IntegerSchema schema = new IntegerSchema();
schema.type = "Int";
schema.max = 10200000000d;
schema.min = 100d;
ObjectMapper m = new ObjectMapper();
System.out.println(m.writeValueAsString(schema));
}
public static class IntegerSchema {
@JsonProperty
String type;
@JsonProperty
double min;
@JsonProperty
@JsonSerialize(using=MyDoubleDesirializer.class)
double max;
}
public static class MyDoubleDesirializer extends JsonSerializer<Double> {
@Override
public void serialize(Double value, JsonGenerator gen, SerializerProvider serializers)
throws IOException, JsonProcessingException {
// TODO Auto-generated method stub
BigDecimal d = new BigDecimal(value);
gen.writeNumber(d.toPlainString());
}
}
}
The trick is to register a custom Serializer for your Double value. This way, you can control what you want.
诀窍是为您的 Double 值注册一个自定义序列化程序。这样，您就可以控制自己想要的东西。
I am using the BigDecimal value to create a String representation of your Double. The output then becomes (for the specific example):
我正在使用 BigDecimal 值来创建 Double 的字符串表示形式。然后输出变为（对于特定示例）：
{"type":"Int","min":100.0,"max":10200000000}
I hope that solves your problem.
我希望这能解决你的问题。
Artur
阿图尔
回答by binh phung
Feature.WRITE_BIGDECIMAL_AS_PLAINset this for your Object Mapper
Feature.WRITE_BIGDECIMAL_AS_PLAIN为您的对象映射器设置此项
