Layui数据表格获取不到后台接口的数据

背景介绍

技术背景

后端写回数据代码 

import com.opensymphony.xwork2.ActionSupport;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

public class AppAction extends ActionSupport {
    public HttpServletResponse getResponse(){
		HttpServletResponse resp = ServletActionContext.getResponse();
		return resp;
	}
    public void writeString(String msg){
		msg = msg==null?"":msg;
		
		getResponse().setCharacterEncoding("utf-8");
		getResponse().setContentType("text/html; charset=utf-8"); 
		PrintWriter pw=null;
		try {
			pw = getResponse().getWriter();
			pw.write(msg);
		} catch (IOException e) {
			log.error("输出异常",e);
		}finally{pw.close();}
	}
}

按照lyaui table组件说明的封装数据

public JSONObject listJson(){
    JSONObject json = new JSONObject();
    json.put("code", 0);
    json.put("count", 0);//数据总数
    json.put("data", "");//sql查询的数据集 List<Object> list
    //调用前面封装好的servlet response 输出流
    writeJson(json);
}

最重要的一步 

layui.use('table',function(){
	table = layui.table;
	table.render({
		elem:'#info',
		autoSort:false,

		contentType:'application/json;charset=utf-8',

		method:'post',
		url:url,
		cols:[[
			{type:'checkbox',width:'3%'}
		]]
		,done:function(res,curr,count){
	}
});