spring-mvc中将json解析为java对象
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Parsing json into java objects in spring-mvc
提问by oksayt
I'm familiar with how to return json from my @Controllermethods using the @ResponseBodyannotation.
我熟悉如何@Controller使用@ResponseBody注释从我的方法中返回 json 。
Now I'm trying to read some json arguments into my controller, but haven't had luck so far. Here's my controller's signature:
现在我正在尝试将一些 json 参数读入我的控制器，但到目前为止还没有运气。这是我的控制器的签名：
@RequestMapping(value = "/ajax/search/sync")
public ModelAndView sync(@RequestParam("json") @RequestBody SearchRequest json) {
But when I try to invoke this method, spring complains that:
Failed to convert value of type 'java.lang.String' to required type 'com.foo.SearchRequest'
但是当我尝试调用这个方法时，spring 抱怨说：
Failed to convert value of type 'java.lang.String' to required type 'com.foo.SearchRequest'
Removing the @RequestBodyannotation doesn't seem to make a difference.
删除@RequestBody注释似乎没有什么区别。
Manually parsing the json works, so Hymanson must be in the classpath:
手动解析 json 有效，因此 Hymanson 必须在类路径中：
// This works
@RequestMapping(value = "/ajax/search/sync")
public ModelAndView sync(@RequestParam("json") String json) {
SearchRequest request;
try {
request = objectMapper.readValue(json, SearchRequest.class);
} catch (IOException e) {
throw new IllegalArgumentException("Couldn't parse json into a search request", e);
}
Any ideas? Am I trying to do something that's not supported?
有任何想法吗？我是否正在尝试做一些不受支持的事情？
采纳答案by skaffman
Your parameter should either be a @RequestParam, ora @RequestBody, not both.
您的参数要么是一个@RequestParam，或者一个@RequestBody，不能同时使用。
@RequestBodyis for use with POST and PUT requests, where the body of the request is what you want to parse. @RequestParamis for named parameters, either on the URL or as a multipart form submission.
@RequestBody用于 POST 和 PUT 请求，其中请求的正文是您要解析的内容。@RequestParam用于命名参数，无论是在 URL 上还是作为多部分表单提交。
So you need to decide which one you need. Do you really want to have your JSON as a request parameter? This isn't normally how AJAX works, it's normally sent as the request body.
所以你需要决定你需要哪一个。你真的想把你的 JSON 作为请求参数吗？这通常不是 AJAX 的工作方式，它通常作为请求正文发送。
Try removing the @RequestParamand see if that works. If not, and you really are posting the JSON as a request parameter, then Spring won't help you process that without additional plumbing (see Customizing WebDataBinder initialization).
尝试删除它@RequestParam，看看是否有效。如果没有，并且您确实将 JSON 作为请求参数发布，那么如果没有额外的管道，Spring 将无法帮助您处理它（请参阅自定义 WebDataBinder 初始化）。
回答by rafael lean ansay
if you are using jquery on the client side, this worked for me:
如果您在客户端使用 jquery，这对我有用：
Java:
爪哇：
@RequestMapping(value = "/ajax/search/sync")
public ModelAndView sync(@RequestBody SearchRequest json) {
Jquery (you need to include Douglas Crockford's json2.js to have the JSON.stringify function):
Jquery（您需要包含 Douglas Crockford 的 json2.js 才能拥有 JSON.stringify 函数）：
$.ajax({
type: "post",
url: "sync", //your valid url
contentType: "application/json", //this is required for spring 3 - ajax to work (at least for me)
data: JSON.stringify(jsonobject), //json object or array of json objects
success: function(result) {
//do nothing
},
error: function(){
alert('failure');
}
});
