Spring REST：嵌套 XML 请求正文的适当构造函数？

Question

我有一个 REST 回调服务，它必须使用以下格式的 XML：

<SearchRequest>
  <SearchCriteria>
    <Param1></Param2>
    <Param2></Param2>
  </SearchCriteria>
</SearchRequest>

实际的 XML 在“Criteria”中有大约 32 个参数，但这给出了基本概念。

我创建了一个 SearchRequest 类，该类具有属性、searchCriteria 和一个 SearchCriteria 类，该类具有 param1 和 param2。

我的 REST 控制器类如下所示：

import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/acme/request/search")
public class AcmeCallbackController {
    @RequestMapping(method = RequestMethod.POST, consumes = "application/xml")
    public ResponseEntity<String> postAcmeSearch(@RequestBody SearchRequest body) {
        StringBuffer resultBuffer = new StringBuffer(2048);
        // implementation code here, 'body' now expected to be a SearchRequest object contructed from request body XML
        return new ResponseEntity<String>(resultBuffer.toString(), HttpStatus.OK);
    } 

当我测试上述服务时，我收到以下错误响应：

`{   "timestamp": 1514390248822,
"status": 400,
"error": "Bad Request",
"exception":  org.springframework.http.converter.HttpMessageNotReadableException",
"message": "JSON parse error: Can not construct instance of SearchRequest: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of SearchRequest: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)\n at [Source: java.io.PushbackInputStream@26bd9717; line: 2, column: 3]",
"path": "/acme/request/search" }`

是否有人知道适用于 SearchRequest 的合适构造函数和/或注释，以便正确反序列化 xml 请求？我在所有 getter 和 setter 上都有 @JsonProperty("{Attribute}") ，其中 {Attribute} 是属性的名称，其初始上限与 XML 元素名称匹配，并且构造函数具有每个属性值的参数.

TIA, 埃德

Answer 1

我想通了。我必须为构造函数参数添加注释，例如

public SearchRequest(@JsonProperty("Param1") String param1,
        @JsonProperty("Param2") String param2) {
    this.param1 = param1;
    this.param2 = param2;
}

之后效果很好。