Javaweb How to pass background data to the foreground page HttpServletResponse and HttpServletRequest

Continue to summarize: After Java passes the action, how to write the data returned in the action to the foreground

First understand the following: HttpServletResponse object

(1). The Web server receives an HTTP request that creates a httpservletrequest and HttpServletResponse object for each request, sends data to the client to find HttpServletResponse, Fetch data from client to find HttpServletRequest;

(2). The HttpServletResponse object can send three types of data to the client: A. Response header B. Status code c. Data
(3). Go to see the HttpServletResponse API yourself
(4). Rsponse return data to the foreground:

A. Use OutputStream to write Chinese to the client:

    Response.setheader ("Content-type", "text/html;charset=utf-8");//Send a response header to the browser, set the browser to decode by UTF-8    String data = "China ";    OutputStream stream = Response.getoutputstream ();    Stream.Write (Data.getbytes ("UTF-8"));

B. Use writer to write Chinese to the client:

   Response.setcharacterencoding ("Utf_8");//Setup response is encoded as UTF-8    response.setheader ("Content-type", "text/ Html;charset=utf-8 ");//Send a response header to the browser, set the browser decoding method for UTF-8, in fact, set the sentence, but also the default setting of response encoding for UTF-8, but the best two sentences in the development of use    // Response.setcontenttype ("Text/html;charset=utf-8"), the same as the code function    printwriter writer = Response.getwriter ();    Writer.write ("China");

Look at how enterprises generally use: no matter how to use, nothing is packaged into a method, to the front desk to return data

Action:

public void searchmodelisused () {<strong>httpservletrequest req = Servletactioncontext.getrequest (); </ Strong>boolean result1 = This.voucherTypeService.queryProductionMode (); if (result1==false) {//non-production mode can modify template 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 + ' '} ');}}

Results are returned to the foreground to display data with Actionwrite

Actionwrite as follows:

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 ();p w.write (Result),} catch (IOException e) {throw new Evoucherexception ("Get HTTP Write Inflow exception "+ e.getmessage ());} finally {if (PW = null) {Pw.close ();}}}

You can see that the Actionwrite method is a HttpServletResponse setting related information and using PrintWriter to write data to the forward table

In the foreground JS, is the response response backstage Pass the data is 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 ("System Prompt", " The current template already has historical data, only the template name and activation date can be modified! "); Isaddvouchermodel = False;refreshaddvouchermodelform (false);} else if (msginfo== ' Is_production_mode ') {Isaddvouchermodel = True;refreshaddvouchermodelform (false);} Else{isaddvouchermodel = True;refreshaddvouchermodelform (false);}}}

Javaweb How to pass background data to the foreground page HttpServletResponse and HttpServletRequest