使用 Jackson 的 ObjectMapper 的 JSON 对象的顺序

json java jackson

2022-08-31 09:34:50

我正在使用ObjectMapper来做我的java-json映射。

ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
ow.writeValue(new File( fileName +".json"), jsonObj);

这是我的java类：

public class Relation {

private String id;
private String source;
private String target;
private String label;
private List<RelAttribute> attributes;

public String getId() {
    return id;
}

public void setId(String id) {
    this.id = id;
}

public String getSource() {
    return source;
}

public void setSource(String source) {
    this.source = source;
}

public String getTarget() {
    return target;
}

public void setTarget(String target) {
    this.target = target;
}

public String getLabel() {
    return label;
}
public void setLabel(String label) {
    this.label = label;
}

public void setAttributes(List<RelAttribute> attributes) {
    this.attributes = attributes;
}

public List<RelAttribute> getAttributes() {
    return attributes;
}

}

这就是我得到的：

{
    "id" : "-75da69d3-79c8-4000-a3d8-b10350a57a7e",
    "attributes" : [ {
      "attrName" : "ID",
      "attrValue" : ""
    }, {
      "attrName" : "Description",
      "attrValue" : "Primary Actor"
    }, {
      "attrName" : "Status",
      "attrValue" : ""
    } ],
    "label" : "new Label",
    "target" : "-46b238ac-b8b3-4230-b32c-be9707f8b691",
    "source" : "-daa34638-061a-45e0-9f2e-35afd6c271e0"
  }

所以我现在的问题是，我如何获得这个json输出：

{
    "id" : "-75da69d3-79c8-4000-a3d8-b10350a57a7e",
    "label" : "new Label",
    "target" : "-46b238ac-b8b3-4230-b32c-be9707f8b691",
    "source" : "-daa34638-061a-45e0-9f2e-35afd6c271e0",
    "attributes" : [ {
      "attrName" : "ID",
      "attrValue" : ""
    }, {
      "attrName" : "Description",
      "attrValue" : "Primary Actor"
    }, {
      "attrName" : "Status",
      "attrValue" : ""
    } ]

  }

我希望它的顺序与我的java声明中的顺序相同。有没有办法指定它？也许有注释或类似的东西？

答案 1

@JsonPropertyOrder({ "id", "label", "target", "source", "attributes" })
public class Relation { ... }

答案 2

您知道有一种方便的方法来指定字母顺序吗？

@JsonPropertyOrder(alphabetic = true)
public class Relation { ... }

如果您有特定要求，请按以下方式配置自定义排序：

@JsonPropertyOrder({ "id", "label", "target", "source", "attributes" })
public class Relation { ... }