返回来自struts2的JSON消息操作

我在我的web应用程序中使用jquery和struts2。现在我需要将谷歌地图嵌入我的网页并添加一些标记。我使用jquery.getJSON（）命令向struts2动作发送请求。返回来自struts2的JSON消息操作

在struts.xml中

<package name="ajax" namespace="/ajax" extends="json-default"> 
    <action name="LatLngList" class="com.test.ajax.Action" method="find"> 
     <result type="json"></result> 
    </action> 
</package>

在网页

<script type="text/javascript"> 
    function readLatLng() { 
     var latitude = new Array(); 
     var longitude = new Array(); 
     $.getJSON("ajax/LatLngList.action?id=9", function(data){ 
      $.each(data, function(i,latlng){ 
      latitude.push(latlng.latitude); 
      longitude.push(latlng.longitude);  
      }); 
     }); 
    } 
</script>

在操作，我读了数据库中的数据，并创建对象的列表，然后使用JSON杰克逊处理器的ObjectMapper到将列表转换为JSON字符串。最后，我返回JSON字符串作为返回值。

public String find() throws JsonGenerationException, JsonMappingException, IOException { 

    List latlngList = new ArrayList(); 
    /* 
    latlngList.add(...); 
    */ 

    ObjectMapper mapper = new ObjectMapper(); 
    String str = mapper.writeValueAsString(latlngList); 
    System.out.println(str); 
    return str; 
}

当我运行Web应用程序，JSON字符串在控制台中显示：

[ 
{"latitude":37.7935697,"longitude":121.181969}, 

{"latitude":37.7852119,"longitude":121.1759833}, 

{"latitude":37.7858117,"longitude":121.1250904}, 

{"latitude":37.794129,"longitude":121.1229535}, 

{"latitude":37.7974078,"longitude":121.0874301}, 

{"latitude":37.8280231,"longitude":121.049312} 
]

然而，它给我的错误。

No result defined for action com.test.ajax.Action and result [{"latitude":37.7935697,"longitude":121.181969},{"latitude":37.7852119,"longitude":121.1759833},{"latitude":37.7858117,"longitude":121.1250904},{"latitude":37.794129,"longitude":121.1229535},{"latitude":37.7974078,"longitude":121.0874301},{"latitude":37.8280231,"longitude":121.049312}] 
    at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:375) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:277) 
    at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176) 
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:263) 
    at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) 
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:133) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207) 
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207) 
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:270) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) 
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:190) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187) 
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52) 
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:498) 
    at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77) 
    at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91) 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:291) 
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859) 
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602) 
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) 
    at java.lang.Thread.run(Thread.java:680)

我搜索了很长时间，但仍找不到解决方案。等待你的帮助。非常感谢你。

来源

2011-09-15 Fan Wu

因为你正在使用JSON插件进行混合，并直接渲染结果。意义既不会工作。操作返回结果的名称，而不是原始数据。（或者说他们可以返回原始数据，但随后必须处理方式不同。）

Check out the documentation for the JSON plugin.

来源

2011-09-15 00:43:02

从我使用Struts2开始已经很长时间了，但是从内存中您不会返回操作的响应，您返回一个简单的字符串名称，用于确定要使用的配置中的哪个结果，然后控制器类可用于您的视图。当返回json结果时，这些属性会被序列化为JSON以返回。

所以，你要更多的东西是这样的：

private List latlngList; 
public List getLatLngList() { 
    return latlngList; 
} 

public String find() throws JsonGenerationException, JsonMappingException, IOException { 
    latlngList = new ArrayList() 
    /* 
    latlngList.add(...); 
    */ 

    return "success"; 
}

然后在您的JavaScript抢生成的JSON的LatLngList财产（注意，从data到data.latLngList的变化）：

<script type="text/javascript"> 
    function readLatLng() { 
     var latitude = new Array(); 
     var longitude = new Array(); 
     $.getJSON("ajax/LatLngList.action?id=9", function(data){ 
      $.each(data.latLngList, function(i,latlng){ 
       latitude.push(latlng.latitude); 
       longitude.push(latlng.longitude);  
      }); 
     }); 
    } 
</script>

来源

2011-09-15 00:41:37 Alconja

非常感谢你。它成功返回JSON文件。我误解了struts2的返回过程。 –

返回来自struts2的JSON消息操作

回答

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