JavaWeb如何将后台数据传递到前台页面HttpServletResponse和HttpServletRequest

继续总结：Java经过Action后，怎么将action中返回的数据写到前台去

先了解下：HttpServletResponse对象

(1).Web服务器收到一个http请求，会针对每个请求创建一个HttpServletRequest和HttpServletResponse对象，向客户端发送数据找HttpServletResponse,从客户端取数据找HttpServletRequest;

(2).HttpServletResponse对象可以向客户端发送三种类型的数据:a.响应头b.状态码c.数据
(3).自己去看HttpServletResponse的API
(4).rsponse向前台返回数据：

a.使用OutputStream向客户端写入中文:

    response.setHeader("Content-type","text/html;charset=UTF-8");//向浏览器发送一个响应头，设置浏览器的解码方式为UTF-8
    String data = "中国";
    OutputStream stream = response.getOutputStream();
    stream.write(data.getBytes("UTF-8"));

b.使用Writer向客户端写入中文:

   response.setCharacterEncoding("UTF_8");//设置Response的编码方式为UTF-8
    response.setHeader("Content-type","text/html;charset=UTF-8");//向浏览器发送一个响应头，设置浏览器的解码方式为UTF-8,其实设置了本句，也默认设置了Response的编码方式为UTF-8，但是开发中最好两句结合起来使用
    //response.setContentType("text/html;charset=UTF-8");同上句代码作用一样
    PrintWriter writer = response.getWriter();
    writer.write("中国");

Action：

public void searchModelIsUsed() {
		<strong>HttpServletRequest req = ServletActionContext.getRequest();</strong>
		boolean result1 = this.voucherTypeService.queryProductionMode();
		if(result1==false){
			//非生产模式则可修改模板
			String result="is_PRODUCTION_MODE";
			this.<strong>actionWrite</strong>("{success:'true',info:'" + result + "'}");
		}else{
			String vmId = req.getParameter("vmId");
			boolean result = this.voucherTypeService.checkVoucherModelUsed(vmId);
			this.actionWrite("{success:'true',info:'" + result + "'}");
		}
	}

actionWrite如下：

	public void actionWrite(String result) {
		if(result == null){
			result = "";
		}
		HttpServletResponse resp = ServletActionContext.getResponse();
		resp.setContentType("text/json;charset=UTF-8");
		resp.setHeader("Cache-Control", "no-cache");
		PrintWriter pw = null;
		try {
			pw = resp.getWriter();
			pw.write(result);
		} catch (IOException e) {
			throw new EVoucherException("获取http写入流异常" + e.getMessage());
		} finally {
			if (pw != null) {
				pw.close();
			}
		}
	}

在前台JS中，就是响应response后台传递过来的数据就OK。

callback : function (options,success,response){
	if(success){
		
		checkSessionOverdue(response.responseText);
		var msg = Ext.JSON.decode(response.responseText);
	var msgInfo = msg.info;
	if(msgInfo == 'true'){
		Ext.Msg.alert("系统提示", "当前模板已存在历史数据，只能修改模板名称跟启用日期！");
		isAddVoucherModel = false;
		refreshAddVoucherModelForm(false);
	}else if(msgInfo=='is_PRODUCTION_MODE'){
		isAddVoucherModel = true;
		refreshAddVoucherModelForm(false);
	}else{
		isAddVoucherModel = true;
		refreshAddVoucherModelForm(false);
	}
		
	}
}

原文：http://blog.csdn.net/itjavawfc/article/details/42645577