用带变量名的表达式计算 JSON object

Question

我们需要评估 json object 中的表达式 java

我们有以下来源 json object

{
  "model":"abc",
  "variant":"m1",
  "stage":2,
  "a":100,
  "b":200,
  "display name":"${model}-${variant}",
  "c":"${a}*${b}",
  "description":"${model}-${variant}-${stage*10}"
}

评估后 json object 应该像

{
  "model":"abc",
  "variant":"m1",
  "stage":2,
  "a":100,
  "b":200,
  "display name":"abc-m1",
  "c":"300",
  "description":"abc-m1-20"
}

表达式可以是 3 种类型

1. 纯算术表达式
2. 连接字符串
3. concat 和算术表达式的组合

我们对源代码 json 中的任何修改持开放态度，以定义表达式表示

问候，普拉纳夫

我们尝试了 https://github.com/json-path/JsonPath但这更像是一种过滤 json

Answer 1

Josson最新版本1.4.2增加了function eval()。

https://github.com/octomix/josson

Josson josson = Josson.fromJsonString(
    "{" +
    "  \"model\": \"abc\"," +
    "  \"variant\": \"m1\"," +
    "  \"stage\" :2," +
    "  \"a\": 100," +
    "  \"b\": 200," +
    "  \"display name\": \"concat(model,'-',variant)\"," +
    "  \"c\": \"round(calc(a+b),0).toText()\"," +
    "  \"description\": \"concat(model,'-',variant,'-',round(calc(stage*10),0))\"" +
    "}");
JsonNode node = josson.getNode(
    "field(display name: eval(display name)," +
    "      c: eval(c)," +
    "      description: eval(description))");
System.out.println(node.toPrettyString());

Output

{
  "model" : "abc",
  "variant" : "m1",
  "stage" : 2,
  "a" : 100,
  "b" : 200,
  "display name" : "abc-m1",
  "c" : "300",
  "description" : "abc-m1-20"
}