扩展Spring MVC 用以支持Controller对Ajax的处理

Spring Mvc中没有特别针对于Ajax请求的处理Controller.但是AbstractController和
SimpleFormController也是可以针对Ajax的请求给与相应的.但显得有一点点的不自然.

	@Override
	protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object cmd,
			BindException ex) {
		String userId=request.getParamater("userId");
                  Map userInfoMap=userDao.getUserBaseInfo(userId);
                  JSONObject object = new JSONObject();
                  object.put("userInfoMap",userInfoMap);
		response.setContentType("text/Xml;charset=gbk");
		PrintWriter out = null;
		try {
			out = response.getWriter();
		         out.println(object.toString());
		         
		}
		catch (IOException ex1) {
			ex1.printStackTrace();
		}finally{
                            out.close();
                   }
		return null;
	}

说明一下我向客户端页面response的是一个JSon对象,选择JSon这种数据格式的两个原因是:

1. 体积小可降低流量.
2. Js端解码十分方便,Js对JSon格式数据有原生的支持.

使用Spring Mvc原有的SimpleFormController,从上边的例子上看是可以实现的,但是每次都要写"将JSonObject写入流,关流的代码.很累,很麻纺."
所以,扩展了两个新的Controller,以简化对Ajax请求的处理.
JSONObjectAbstractController 用于简单的从request.getParamater参数的情况.
JSONObjectAbstractController 的原代码:

package com.javaest.ext.spring.mvc.controller;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONObject;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;

public abstract class JSONObjectAbstractController extends AbstractController {

	@Override
	protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		JSONObject jsonObject = handleAjaxRequestInternal(request, response);
		response.setContentType("text/Xml;charset=gbk");
		PrintWriter out = null;
		try {
			out = response.getWriter();
			out.println(jsonObject.toString());
		}
		catch (IOException ex1) {
			ex1.printStackTrace();
		}
		finally {
			out.close();
		}

		return null;
	}

	protected abstract JSONObject handleAjaxRequestInternal(HttpServletRequest httpServletRequest,
			HttpServletResponse httpServletResponse) throws Exception;

}

JSONObjectSimpleFormController 用于自动将请求参数绑定到Command对象的情况.
JSONObjectSimpleFormController 的代码:

package com.javaest.ext.spring.mvc.controller;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONObject;

import org.springframework.validation.BindException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.SimpleFormController;

public abstract class JSONObjectSimpleFormController extends SimpleFormController {

	@Override
	protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object cmd,
			BindException ex) {
		JSONObject object = onAjaxSubmit(request, response, cmd, ex);

		response.setContentType("text/Xml;charset=gbk");
		PrintWriter out = null;
		try {
			out = response.getWriter();
			out.println(object.toString());
		}
		catch (IOException ex1) {
			ex1.printStackTrace();
		}
		finally {
			out.close();
		}

		return null;
	}

	public abstract JSONObject onAjaxSubmit(HttpServletRequest request, HttpServletResponse response, Object cmd,
			BindException ex);

}

以下就是我为了支持Ajax请求的处理所扩展的SpringMvc Controller.
作者来自长春,一直在基于J2EE架构开发税务方面的应用.