从struts2动作返回JSON消息

Question

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.

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>

在网页中

<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>

在操作中,我从数据库中读取数据并创建对象列表,然后使用jackson json处理器的ObjectMapper将List转换为JSON字符串.最后,我将JSON String作为返回值返回.

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应用程序时,控制台中显示JSON String:

[
{"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}
]

但是,它给了我错误.

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)

我已经搜索了很长时间但仍无法找到解决方案.等待你的帮助.非常感谢你.

Answer 1

它已经,因为我用Struts2的很长一段时间,但是从内存中,你无法返回的动作你的回应,你返回,确定一个简单的字符串名称而导致的配置使用,然后在控制器类的属性变为可用你的看法.返回json结果时,会将这些属性序列化为JSON以便返回.

所以你想要更像这样的东西:

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

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

    return "success";
}

然后在你的javascript中获取LatLngList生成的JSON 的属性(注意更改data为data.latLngList):

<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>