How to get the filed value of Module's Object?

Dear：

I get it ， I must use x.data.name;

but , another question is, Use Proxy

Code:

<script type="text/jscript">  
Ext.require(['Ext.grid.*',   'Ext.data.*'  ]);  
var x;
Ext.onReady(function(){  
    
  Ext.define('Student', {
    extend: 'Ext.data.Model',
    fields:[{name:"id",type:"string"},
            {name:"name",type:"string"},  
            {name:"class",type:"string",convert:function(val){  
                     if(val=="1"){return "A"};  
                     if(val=="2"){return "B"};  
                     if(val=="3"){return "C"};   }
                  }  
            ], 
     proxy: {type: 'ajax',  
             url: '4.15b.json', 
             reader: {  
                type: 'json', 
                root: 'items',  
                //totalProperty  : 'total'  
            }  
        },  
        autoLoad: true  
     
  });
  

  x = Ext.ModelManager.getModel('Student');

//Uses the configured RestProxy to make a GET request to /users/123
x.load("002", {
    success: function(user) {
        console.log(user.data.name); //logs 123
      // alert(user.getName());
    }
});


}) 
</script>

4.15b.json ：

Code:

 {   
items: [   
  {id:"001",name: "PA",class:"1"},   
  {id:"002",name:"LP",class:"2"},  
  {id:"003",name: "GY",class:"1"}  
         ]   
}

Q1. Does the load 1st param , must use id? or the column name must id?

Q2.i Load 002, but its still show PA (001's name)?

thx