1. ajax跨域的是利用了动态加载js文件没有跨域限制的特性。

2. 服务端返回jsonp格式的文本：xx({weather:"晴天",temp:"30C",:wind:"东南风"});

    这本质上是一个函数调用语句，实参为json对象，函数名为xx。

3. 客户端：利用jquery插件：jquery.jsonp-2.4.0.js

   代码：  

<script type="text/javascript">

  function xx(data)

  {

   alert(data);

   if(data)

             {

              var weatherStr = "今日天气:&nbsp;&nbsp;";

              weatherStr +=  data.weather + "&nbsp;&nbsp;";

              weatherStr +=  data.temp + "&nbsp;&nbsp;";

              weatherStr +=  data.wind + "<br/>";

     alert(weatherStr);

                 document.getElementById("weather_zone").innerHTML = weatherStr;

    }

  }

  function getCurrentDayWeather()

  {

   var currentDayWeatherUrl = "";

   $.jsonp({url: 'http://localhost:9090/httpapi/service/weather/detail/101190501.json?callback=xx'});

    

  }

  

  </script>

 

4. 服务端RestEasy的使用：

@Component("weatherService")

@Transactional

@Path("weather")

public class WeatherService

{

    @Autowired

    private WeatherDao weatherDao = null;

    

    public Weather queryById(String id)

    {

        Weather weather = weatherDao.get(id);

       

        return weather;

    }

   

    @GET

    @Path("/detail/{cityCode}.json")

    @Produces("application/json")

    public Weather getCurrentDayWeather(@PathParam("cityCode") String cityCode)

    {

        Weather weather = weatherDao.get(DateTimeUtil.getCurrentDay() + "_"

                + cityCode);

       

        if (null == weather || StringUtils.isEmpty(weather.getWeather()))

        {

            Weather emptyWeather = new Weather();

            emptyWeather.setWeatherId(DateTimeUtil.getCurrentDay() + "_"

                    + cityCode);

            emptyWeather.setWeather("暂无实况");

            emptyWeather.setTemp("暂无实况");

            emptyWeather.setWind("暂无实况");

           

            return emptyWeather;

        }

       

        return weather;

    }

    这个Rest接口只能返回 json，不能返回jsonp。

     RestEasy官方文档的21.2小结有几句话，基本是一句带过：

    

      

21.2. JSONP Support

If you're use Jackson  is supported right away. If the media type of the response is json and a callback query parameter is given, the response will be a javascript snippet with a method call of the method defined by the callback parameter. For example:

GET /resources/stuff?callback=processStuffResponse

will produce this response:

processStuffResponse(
    
     )
    

This supports the default behavior of .

You can change the name of the callback parameter by setting the callbackQueryParameter property.

 

我用了Jackson ，可是总返回不了jsonp，老是返回json。

后来google到了老外的帖子（），

发现可能是我的RestEasy版本低的问题，我的是2.3.3，说高版本的支持的，我懒得换高版本，于是把那个帖子中老外DIY的代码拿来用了：

思路是自己建个Filter，Wrap HttpServletRequest和HttpSerletResponse，自己把返回的json转成jsonp。

代码如下：

I make draft workaround for this problem. Try it. This solution takes data via http get parameters and translate to virtual POST request.

JQuery:

function call(){
          var val ='{"routes":[{"arrivalAddress":{"fullAddress":"DME"},"destinationAddress":{"fullAddress":"SVO"}}],"carsCount":"1"}';var jHandler ="doMap";$.getJSON("http://xxx:yyy/app-0.0.0.1/rest/requestPrice?callback="+ jHandler +"&json="+ encodeURIComponent(val)+"&jsoncallback=?",null,null,"json");}function doMap(obj){
          alert(obj);}

Declaration in Service interface

@POST @Path("requestPrice") @Produces("application/json") @Consumes("application/json") PriceResponse requestPrice(PriceRequest request)throwsServiceException;

Filter class:

import javax.servlet.*;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletRequestWrapper;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpServletResponseWrapper;import java.io.*;import java.util.Enumeration;import java.util.HashMap;import java.util.Iterator;import java.util.Map;publicclassJSONPRequestFilterimplementsFilter{
          privateString callbackParameter;publicvoid doFilter(ServletRequest request,ServletResponse response,FilterChain chain)throwsIOException,ServletException{
          if(!(request instanceofHttpServletRequest)){
          thrownewServletException("This filter can "+" only process HttpServletRequest requests");}finalHttpServletRequest httpRequest =(HttpServletRequest) request;finalHttpServletResponse httpResponse =(HttpServletResponse) response;if(isJSONPRequest(httpRequest)){
          RequestWrapper requestWrapper =newRequestWrapper(httpRequest);            requestWrapper.setContentType("application/json; charset=UTF-8");            requestWrapper.setHeader("cache-control","no-cache");            requestWrapper.setHeader("accept","application/json");            requestWrapper.setCharacterEncoding("UTF-8");            requestWrapper.setBody(httpRequest.getParameter("json"));finalByteArrayOutputStream baos =newByteArrayOutputStream();HttpServletResponseWrapper responseWrapper =newHttpServletResponseWrapper(httpResponse){
          @OverridepublicServletOutputStream getOutputStream()throwsIOException{
          returnnewServletOutputStream(){
          @Overridepublicvoid write(int b)throwsIOException{
                                      baos.write(b);}};}@OverridepublicPrintWriter getWriter()throwsIOException{
          returnnewPrintWriter(baos);}publicString getData(){
          return baos.toString();}};            chain.doFilter(requestWrapper, responseWrapper);            response.getOutputStream().write((getCallbackParameter(httpRequest)+"(").getBytes());            response.getOutputStream().write(baos.toByteArray());            response.getOutputStream().write(");".getBytes());            response.setContentType("text/javascript");}else{
                      chain.doFilter(request, response);}}privateString getCallbackMethod(HttpServletRequest httpRequest){
          return httpRequest.getParameter(callbackParameter);}privateboolean isJSONPRequest(HttpServletRequest httpRequest){
          String callbackMethod = getCallbackMethod(httpRequest);return(callbackMethod !=null&& callbackMethod.length()>0);}privateString getCallbackParameter(HttpServletRequest request){
          return request.getParameter(callbackParameter);}publicvoid init(FilterConfig filterConfig)throwsServletException{
                  callbackParameter = filterConfig.getInitParameter("callbackParameter");}publicvoid destroy(){
          }void printRequest(HttpServletRequest request)throwsIOException{
          {
          System.out.println("--------------Headers---------------");Enumeration en = request.getHeaderNames();while(en.hasMoreElements()){
          String val = en.nextElement().toString();System.out.println(val +" :");Enumeration en1 = request.getHeaders(val);while(en1.hasMoreElements()){
          System.out.println("\t"+ en1.nextElement());}}}{
          System.out.println("------------Parameters--------------");Enumeration en = request.getParameterNames();while(en.hasMoreElements()){
          String val = en.nextElement().toString();System.out.println(val +" :");String[] en1 = request.getParameterValues(val);for(String val1 : en1){
          System.out.println("\t"+ val1);}}}System.out.println("---------------BODY--------------");BufferedReader is = request.getReader();String line;while((line = is.readLine())!=null){
          System.out.println(line);}System.out.println("---------------------------------");System.out.println("ContentType: "+ request.getContentType());System.out.println("ContentLength: "+ request.getContentLength());System.out.println("characterEncodings: "+ request.getCharacterEncoding());System.out.println("AuthType: "+ request.getAuthType());System.out.println("ContextPath: "+ request.getContextPath());System.out.println("Method: "+ request.getMethod());}publicstaticclassRequestWrapperextendsHttpServletRequestWrapper{
          Map
         
           headers =newHashMap
          
           ();int contentLength;BufferedReader reader;publicRequestWrapper(HttpServletRequest request){
          super(request);}publicvoid setHeader(String key,String value){
                      headers.put(key, value);}ByteArrayInputStream bais;publicvoid setBody(String body){
                      bais =newByteArrayInputStream(body.getBytes());            contentLength = body.length();            headers.put("content-length",Integer.toString(contentLength));}@OverridepublicBufferedReader getReader()throwsIOException{
                      reader =newBufferedReader(newInputStreamReader(bais));return reader;}@OverridepublicServletInputStream getInputStream()throwsIOException{
          returnnewServletInputStream(){
          @Overridepublicint read()throwsIOException{
          return bais.read();}};}@OverridepublicString getMethod(){
          return"POST";}privateString contentType;publicvoid setContentType(String contentType){
          this.contentType = contentType;            headers.put("content-type", contentType);}@OverridepublicString getContentType(){
          return contentType;}@Overridepublicint getContentLength(){
          return contentLength;}@OverridepublicString getHeader(String name){
          String val = headers.get(name);if(val !=null){
          return val;}returnsuper.getHeader(name);//To change body of overridden methods use File | Settings | File Templates.}@OverridepublicEnumeration getHeaders(finalString name){
          returnsuper.getHeaders(name);}@OverridepublicEnumeration getHeaderNames(){
          finalEnumeration en1 =super.getHeaderNames();finalIterator it = headers.keySet().iterator();returnnewEnumeration(){
          publicboolean hasMoreElements(){
          return en1.hasMoreElements()|| it.hasNext();}publicObject nextElement(){
          return en1.hasMoreElements()? en1.nextElement():(it.hasNext()? it.next():null);}};}@Overridepublicint getIntHeader(String name){
          String val = headers.get(name);if(val ==null){
          returnsuper.getIntHeader(name);}else{
          returnInteger.parseInt(val);}}}}
          
         

web.xml

          
          
           JSONPRequestFilter
           
          
           xxxxx.JSONPRequestFilter
           
           
           
            callbackParameter
            
           
            callback
            
           
          
          
          
           JSONPRequestFilter
           
          
           /rest/*
          
         

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3,899 19 38

answered Mar 25 '11 at 12:06 41 1

1

An enhancement to support JSONP is scheduled to be released in RESTEasy 2.3.6 Final/3.0-beta-4 (). I was able to "backport" it my project which uses RESTEasy 2.3.5 by simply copying . RESTEasy automatically picks up the new provider based on the annotation. It works automatically by wrapping your results in a js callback once it sees a query parameter named "callback" in the url. This is compatible with what JQuery sends to the server for JSONP requests.