servlet + Extjs + ext.ajax.request（亲测可用）

1.js代码

Ext.onReady(function(){
  
    Ext.Ajax.request({
    
        url:"AjaxServlet.do?name=里杂谈",
        //url:"AjaxServlet.do",
        method:"get",
        //params:{name:"xxx"},
        
        success:function(res,config){
            alert(config.url);
            alert(config.method);
            
            alert(res.responseText);
            //var json = res.responseText;
            var json = Ext.util.JSON.decode(res.responseText);
            
            alert("xx");
            Ext.MessageBox.alert("提示",json.author);
        },
        failure:function(){
            Ext.MessageBox.alert("result","请求失败")
            
        }
    });

})

2.servlet

System.out.println("+++++");
        response.setContentType("text/html,charset=utf-8");
        PrintWriter out = response.getWriter();
        String name1 = request.getParameter("name");
        String name = "'"+name1+"'";
        System.out.println(name);
        Date date = new Date();
        //String time = date.toString();
        //String json = "{authon:" + name + ",time:" + time + "}";
        String json = "{author:"+name+"}";//转换成json。格式{name:"name"},而不是{name:name}
        
        out.println(json);
        
        System.out.println(json);
        out.flush();
        out.close();

web.xml配置