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() {	HttpServletRequest req = ServletActionContext.getRequest();	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.actionWrite("{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);	}	}}