ext combobox Store 动态获取值

ext 部分:
// 从后台加载籍贯信息,动态加载 显示到ComboBox中 
第一个方法java

//将数据加载到本地
第2个方法 (推荐 方便)
var nativeStore =new Ext.data.JsonStore({

   url:'exam/ExamCourseAction',
    root:'courseName',
   fields:[{name:'course'}]
    
});
第3个方法
 

//comboBox 

{                              
                                                 xtype :'combo',
                                                 fieldLabel :'科目',
                                                 name :'tType',
                                                 hiddenName :'course',
                                                 anchor :'95%',
                                                 editable :false,
                                                triggerAction : 'all',
                                                 store :nativeStore,
                                                //mode:'local',
//用第一个或第二个方法的时候要加mode:'local'用第二个方法的时候不要加 或者改为mode:'remote'
                                                 emptyText :'请选择',
                                                 displayField: 'course',
                                                 valueField :'course'
                                              }




action 部分:
<package name="exma" extends="json-default"namespace="/exam">
       <action name="ExamCourseAction"class="org.action.ExamCourseAction">
          <result type="json">
              <paramname="root">course</param> 
          </result>
       </action>
    </package>
java代码部分 :  package org.action; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class ExamCourseAction {     privateMap<String, Object> course=  new HashMap<String,Object>();         publicString execute(){              Map<String, Object> map1 = newHashMap<String, Object>();       map1.put("course", "java");       Map<String, Object> map2 = newHashMap<String, Object>();       map2.put("course", "c");       Map<String, Object> map3 = newHashMap<String, Object>();       map3.put("course", "vb");              List<Object>  ls =new ArrayList<Object>();       ls.add(map1);       ls.add(map3);       ls.add(map2);              this.course.put("courseName", ls);              System.out.println("ssssssssss");        return"success";        }     publicMap<String, Object> getCourse(){        returncourse;     }     public voidsetCourse(Map<String, Object> course){        this.course= course;     } }