使用 java 库将 CSV 数据转换为嵌套的 json 对象

Question

我正在搜索可以转换包含嵌套对象（如：address.city、address.country）的 csv 数据的 java 库，以相应地转换为带有嵌套对象的 json 数据。 下面是我正在使用的java代码：

File input = new File("input.csv");
File output = new File("output.json");

CsvSchema csvSchema = CsvSchema.builder()
.setUseHeader(true).build();
    CsvMapper csvMapper = new CsvMapper();

    // Read data from CSV file
    List<Object> readAll = csvMapper.readerFor(Map.class).with(csvSchema).readValues(input).readAll();
    System.out.println(readAll);
    ObjectMapper mapper = new ObjectMapper();

    // Write JSON formated data to output.json file
    mapper.writerWithDefaultPrettyPrinter().writeValue(output, readAll);

    // Write JSON formated data to stdout
    System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(readAll));

这是我得到的输出：

[ {
 "studentName" : "Foo",
 "Age" : "12",
 "address__city" : "newyork",
 "address__address1" : "North avenue",
 "address__zipcode" : "123213",
 "subjects__name" : "English",
 "subjects__marks" : "40"
  }, {
 "studentName" : "ABcd",
 "Age" : "25",
 "address__city" : "achi",
 "address__address1" : "Morh",
 "address__zipcode" : "27400",
 "subjects__name" : "History",
 "subjects__marks" : "50"
 } ]

这是预期的输出：

{
"studentName": "Foo",
"Age": "12",
"address":{
    "city" : "newyork",
    "address1": "North avenue",
    "zipcode" : "123213"
},
"subjects": [
    {
        "name": "English",
        "marks": "40"
    },
    {
        "name": "History",
        "marks": "50"
    }
]
}

这是输入 csv：

"studentName","Age","address__city","address__address1","address__zipcode","subjects__name","subjects__marks"
"Foo","12","newyork","North avenue","123213","English","40"
"","25","achi","Morh","2400","History","

Answer 1

看起来univocity-parsers 可以通过其@Nested 注释在CSV 端完成您需要的操作。

虽然读/写 JSON 是行不通的。所以我的建议是使用单义解析器将您的 CSV 解析为您需要的对象结构，然后 Jackson 将该对象结构写入 JSON。

希望这会有所帮助。 披露：我是单义词解析器的作者。它是开源和免费的（Apache 2.0 许可证）