在DefaultServlet-servlet.xml 添加

     
     在类中添加 @ResponseBody 注解

 

工具类处理json 

public class ResponseUtil {

public static void write(HttpServletResponse response,Object o)throws Exception{

response.setContentType("text/html;charset=utf-8");

PrintWriter out=response.getWriter();

out.println(o.toString());

out.flush();

out.close();

}

}