This is actually quite easy using Spring 3.0 and above. In looking at the examples above however I am confused as to why you are treating the spring controller like a plain servlet and printing directly to the response stream. This should be avoided. You would be much better off using just returning a POJO representing your JSON array and let a JSON parser create the response.

The first task is to get Spring to return JSON. This is easily handled by adding @ResponseBody to your controller, telling the controller to serialize the POJO to the client. If you have Jackson in your classpath this will automatically be sent as JSON using the MappingJacksonHttpMessageConverter which is enabled with mvc:annotation-driven.

But JSON isn t enough. You want JSON-P, assuming that the client wants to use the JSON in a cross domain scenario. This can be accomplished in a number of different ways. You could implement a servlet filter using Spring s DelegatingFilterProxy. The filter can determine if JSON-P is being requested and you can tune the response accordingly.

So for my uses I prefer to extend the Spring 3.0 (+) MappingJacksonJsonView instead of a filter and check if the request param contained a key of "callback". If I want JSON or JSONP I can simply add a second servlet mapping to *.jsonp and send either JSON or JSONP based on the presence of the callback parameter.

该守则是:

在你的控制人员中规定如下:

@RequestMapping(value="/ad", method=RequestMethod.GET)
public ModelMap getAvailabilityModel(@RequestParam(required = false) String callback) {
    ModelMap modelMap = new ModelMap();
    modelMap.addAttribute("html", "<strong>Hello World!</strong>");
    return modelMap;
}   

回归模式 地图或甚至《安第斯山季刊》使我能够根据“保护状”地图做不同的事情。

这里的习俗是,要处理初等人物的延伸(只是为了简便而排除某些压倒性):

public class MappingJacksonJsonpView extends MappingJacksonJsonView {

@Override 
public void render(Map<String, ?> model, HttpServletRequest request, HttpServletResponse response) throws Exception {

if("GET".equals(request.getMethod().toUpperCase())) {

    Map<String, String[]> params = request.getParameterMap();

    if(params.containsKey("callback")) {
    String callbackName = params.get("callback")[0];
    response.getOutputStream().write(new String(callbackName + "(").getBytes());
    log.info("GETTER Found for a .jsonp method, callback name is : " + callbackName);
    super.render(model, request, response);
    response.getOutputStream().write(new String(");").getBytes());
    response.setContentType("application/javascript");
    }

    else {
    super.render(model, request, response);
    }
}

else {
    super.render(model, request, response);
}
  }
 }

如果将请求编为*.jsonp,我把“召回”作为我假定的JSON-P的关键参数列入请求参数,我把警示信息放在答复上游。 我将允许Jackson JSON加工商处理在所有情况下将POJO改为适当的JSON的具体细节。 我在我的控制员中,我只是回去了一张POJO或一个模型Map;在答复中,我没有穿过我自己的JSON。 或者,我本可以采用一种模式,对返回类型的看法。 这样就可以妥善处理*.do诉*json的请求。 利用火药,确保你在应急负责人、JSON的申请/json以及JSON-P的申请/javascript中找到适当的媒体。

and for a filter solution: