我的应用程序 null 值不会被序列化为 json,这没问题。但在一种特定情况下,我希望将空值发送给客户端。我怎样才能做到这一点?
class User {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
对于这个类,我尝试使用 JsonInclude.Always,但其默认值稍后会在配置中被覆盖。
最佳答案
使用JsonIninclude
注释。示例:
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.databind.ObjectMapper;
public class Test {
public static void main(String[] args) throws Exception {
ObjectMapper mapper = new ObjectMapper();
mapper.setSerializationInclusion(Include.NON_NULL);
System.out.println(mapper.writeValueAsString(new User()));
}
}
@JsonInclude
class User {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
上面的代码打印:
{"name":null}
JsonInclude
中的默认值为 ALWAYS
:
/**
* Inclusion rule to use for instances (values) of types (Classes) or
* properties annotated.
*/
public Include value() default Include.ALWAYS;
其他选项是使用 JsonSerialize
注释:
@JsonSerialize(include = Inclusion.ALWAYS)
class User {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
结果与 JsonInclude
相同。
关于java - 覆盖全局 jackson 配置,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/54782829/