JavaWeb如何将后台数据传递到前台页面HttpServletResponse和HttpServletRequest_html/css_WEB-ITnose
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2022-04-19 12:41:35
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继续总结:Java经过Action后,怎么将action中返回的数据写到前台去
可以看到actionWrite方法就是一个HttpServletResponse设置相关信息后利用PrintWriter向前台写数据
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 + "'}"); } }上面得到结果result,向前台返回显示数据用actionWrite
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(); } } }
可以看到actionWrite方法就是一个HttpServletResponse设置相关信息后利用PrintWriter向前台写数据
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); } }}
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