Java Controller 未将 JSON 转换为实体

Question

我无法从通过 POST 请求发送的 JSON 中接收信息，如下所示:

[{
 "idVehicule": 1,
 "vacancies": 3
}]

我有一个简单的 Controller ，尝试获取从前面发送的 JSON，将其转换为 testModel:

import com.fasterxml.jackson.annotation.JsonProperty;

public class testModel {

    @JsonProperty( "idvehicle" )
    private int idvehicle;
    @JsonProperty( "vacancies" )
    private String vacancies;

    public int getIdvehicle() {
        return idvehicle;
    }
    public void setIdvehicle(int idvehicle) {
        this.idvehicle = idvehicle;
    }
    public String getVacancies() {
        return vacancies;
    }
    public void setVacancies(String vacancies) {
        this.vacancies = vacancies;
    }

}

然后它只打印它的值之一。

@RequestMapping(value = "/vehicle", method = RequestMethod.POST)
    public ResponseEntity<String> vehicleTest(@RequestBody testModel testModel){
        System.out.println(testModel.getVacancies());
        return new ResponseEntity<String>(HttpStatus.OK);;
    }

尝试使用 postman 的方法后，我不断收到此错误:

{
  "timestamp": 1472819769941,
  "status": 400,
  "error": "Bad Request",
  "exception": "org.springframework.http.converter.HttpMessageNotReadableException",
  "message": "Could not read document: Can not deserialize instance of testModel out of START_ARRAY token\n at [Source: java.io.PushbackInputStream@646345e6; line: 1, column: 1]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of testModel out of START_ARRAY token\n at [Source: java.io.PushbackInputStream@646345e6; line: 1, column: 1]",
  "path": "/vehicle"
}

我也尝试过更改 JSON，然后问题是该方法无法将其转换为实体，使得变量“testModel”始终为 null

{"testModel":{"idvehicle":1,"vacancies":3}}

删除“@RequestBoby”注释会产生与之前段落相同的问题。

有什么想法可以帮助我解决这个问题吗？谢谢

Answer 1

您正在指定@JsonProperty如idvehicle在你的testModel所以更正JSON您要发布到:

 [{
     "idvehicle": 1,
     "vacancies": 3
 }]

接下来，您将发送 testModel 的数组并期待testModel这当然不会反序列化。

更正JSON您正在发送至{"idvehicle": 1,"vacancies": 3}或更改 Controller接受 testModel 的数组如下:

@RequestMapping(value = "/vehicle", method = RequestMethod.POST)
public ResponseEntity<String> vehicleTest(@RequestBody List<testModel> testModel){

        return new ResponseEntity<String>(HttpStatus.OK);;
}