![](/img/trans.png)
[英]Retrofit + Robospice JSON return POJO with Null for nested field
[英]Json to POJO null field
服务接收到这个 JSON:
{
"fieldA" : null
}
或者这个:
{
"fieldB" : null
}
java class model 是:
@Data
public class MyRequest implements Serializable {
private Integer fieldA;
private Integer fieldB;
}
服务是:
@PostMapping
@Produces({MediaType.APPLICATION_JSON})
@Consumes(value = {MediaType.APPLICATION_JSON})
public ResponseEntity<MyResponse> process(@RequestBody @Valid MyRequest request)
throws URISyntaxException {
Integer a = request.getFieldA();
Integer b = request.getFieldB();
...
}
这里 a 和 b 整数都是 null 与两个请求。
有没有办法知道该字段是否在 json 中设置为 null 或者是否因为未设置而设置为 null?
我想区分这两个请求
您可以选择任何默认值并将其视为是否设置字段的标记。 如果字段设置为默认值,则表示JSON
有效负载中没有给定字段。 看看下面的例子:
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.Data;
import java.io.IOException;
import java.io.Serializable;
public class JsonApp {
public static void main(String[] args) throws IOException {
ObjectMapper mapper = new ObjectMapper();
MyRequest reqA = mapper.readValue("{\"fieldA\" : null}", MyRequest.class);
System.out.println(reqA);
System.out.println("Is fieldA set: " + reqA.isFieldASet());
System.out.println("Is fieldB set: " + reqA.isFieldBSet());
MyRequest reqB = mapper.readValue("{\"fieldB\" : null}", MyRequest.class);
System.out.println(reqB);
System.out.println("Is fieldA set: " + reqB.isFieldASet());
System.out.println("Is fieldB set: " + reqB.isFieldBSet());
}
}
@Data
class MyRequest implements Serializable {
private final Integer DEFAULT = Integer.MIN_VALUE;
private Integer fieldA = DEFAULT;
private Integer fieldB = DEFAULT;
public boolean isFieldASet() {
return !DEFAULT.equals(fieldA);
}
public boolean isFieldBSet() {
return !DEFAULT.equals(fieldB);
}
}
上面的代码打印:
MyRequest(DEFAULT=-2147483648, fieldA=null, fieldB=-2147483648)
Is fieldA set: true
Is fieldB set: false
MyRequest(DEFAULT=-2147483648, fieldA=-2147483648, fieldB=null)
Is fieldA set: false
Is fieldB set: true
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.