Question

我正在使用Spring Boot并尝试接受POST。

我收到错误消息

Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: 
Could not read document: Can not construct instance of biz.ianw.ukData.restServer.Controller$Car: 
no suitable constructor found, can not deserialize from Object value (missing default constructor 
or creator, or perhaps need to add/enable type information?)

at [Source: java.io.PushbackInputStream@24b515ad; line: 1, column: 2]; nested exception is 
com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of biz.ianw.ukData.restServer.Controller$Car: 
no suitable constructor found, can not deserialize from Object value (missing default constructor 
or creator, or perhaps need to add/enable type information?)

at [Source: java.io.PushbackInputStream@24b515ad; line: 1, column: 2]

我测试的代码是：

public class Car {
    private String color;       
    public Car() {}     
    public Car(String color) { this.color = color; }
    public String getColor() {  return color; }
    public void setColor(String color) { this.color = color; }
}

@RequestMapping(value="/search", method=RequestMethod.POST)
public @ResponseBody String doSearch(@RequestBody Car data) {   
    logger.info("in search: {}", data); 
    return new String("Done.");     
}

我正在使用jQuery发送POST：

    datablock.urlpath = "search";
    datablock.type = "POST";
    datablock.contentType = "application/json; charset=utf-8";

    datablock.data = { color: "Blue" };

    $.ajax({
            type: datablock.type,
            url: server + datablock.urlpath,
            contentType: datablock.contentType,
            data: JSON.stringify(datablock.data)
        })
        .then(function (data) {
            console.log("ajaxCall success: " + JSON.stringify(datablock) + " -> " + JSON.stringify(data));
        })
        .fail(function (xhr, status, err) {
            var response = JSON.parse(xhr.responseText);
            console.log("ajaxCall failure: " + JSON.stringify(datablock) + " -> " + response.message);
        });

默认构造函数存在且标题和正文似乎正确，显示了预期的内容类型和有效负载：

encodesCreativeWork

所以我有点不知所措地解释错误信息。有什么建议我错过了吗？

Answer 1

问题是目标类，在这种情况下，Car 不能是非静态内部类。它不像在问题中那样嵌入在Controller类中。

详细信息在here中，但归结为Java添加内部类的方式意味着他们没有Jackson所需的默认构造函数。

Answer 2

我遇到了同样的问题，但是我和你之间存在细微差别，我从未添加过默认构造函数，在添加相同内容之后，应用就像Gem一样。

＆＃34;无法构建实例＆＃34;收到带有JSON有效负载的POST

2 个答案: