Struts2 in Action class implements the interface ModelDriven problem !

Just do the project using Struts2 , he would face a series of problems, the most eggs pain mainly to the following questions , seek help heroes look , first thank you !
1, each execution of a method in the Action class is executed twice getModel method ;
2, do the update feature , the first time the page jump to update the data is blank , and the second piece of data before the jump is to display the information , search the Internet less, said it would "ModelDrivenInterceptor provides a configuration parameter : refreshModelBeforeResult, as long as it is defined as true, the problem has been solved ! "What is configured in Struts.xml do ?
My struts.xml configuration is as follows , but no matter , the solution ! ! ! !





name = "refreshModelBeforeResult">
true







method = "showAllNewInfo">
true

. / back / news / showAllNewsInfo.jsp



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limited, I do not understand your question ! can code did you get to see it
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master all go ah , their top one
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  This reply was moderator deleted at 2012-07-11 15:17:55

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  This reply was moderator deleted at 2012-07-11 16:20:55

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possible
Action class code :

public class NewsAction extends BaseAction implements ModelDriven {

private NewsServiceImpl newsService; / / Press service layer interface class

private NewsDTO newsInfo = new NewsDTO (); / / instantiate News category

/ **
* Get all the news and information
*
* @ return
* @ throws Exception
* /
public String showAllNewInfo () throws Exception {
if (null! = newsInfo) {
String title = newsInfo.getTitle ();
String newType = newsInfo.getNewtype ();
if (null! = title)
newsInfo.setTitle (title);
if (newType! = null)
newsInfo.setNewtype (newType);
}

pageInfo.setPageNo (pageNo); / / set page
newsService.getAllNewsByPage (newsInfo, pageInfo);

/ / assign all the news and information "newsList" variable
newsList = pageInfo.getList ();

pageMap.put ("pageNo", pageInfo.getPageNo ());
pageMap.put ("pageSize", pageInfo.getPageSize ());
pageMap.put ("pageTotal", pageInfo.getPageTotal ());
pageMap.put ("recTotal", pageInfo.getRecTotal ());

return this.SUCCESS;
}

/ **
* Add News
*
* @ return
* @ throws Exception
* /
public String doInsertNewInfo () throws Exception {
String newCode = randomNum.getTimeStamp ("N_");
long readNum = 1;
newsInfo.setNewcode (newCode);
newsInfo.setPublishtime (new Date ());
newsInfo.setReadnumber (readNum);
boolean flag = newsService.doInsertNews (newsInfo);
if (flag) {
newsInfo.setTitle (null);
newsInfo.setNewtype (null);
messages = " Add succeed ! ' ;
return this.showAllNewInfo ();
} else {
messages = " Sorry , the information added Failed ! Please confirm whether the required fill in ! ' ;
return this.INPUT;
}
}

/ **
* Number delete news and information according to news
*
* @ return
* @ throws Exception
* /
public String doDelNewInfo () throws Exception {
/ / Get news Numbers
String newsCode = request.getParameter ("code");
/ / call the Delete method
boolean flag = newsService.doDelNewsByCode (newsCode);
/ / According to "flag" the return value gives the corresponding message
if (flag) {
messages = " information has been successfully deleted ! ' ;
} else {
messages = " Sorry , the information Delete Failed ! ' ;
}
return this.showAllNewInfo ();
}

/ **
* updated news and information methods
*
* @ return
* @ throws Exception
* /
public String doModifyNewInfo () throws Exception {

return this.SUCCESS;
}

/ **
* news and information according to a news Lookup Method
*
* @ return
* @ throws Exception
* /
public String showNewInfo () throws Exception {
/ / Get news Numbers
String newsCode = request.getParameter ("code");
/ / invoke methods to obtain news entity information
newsInfo = newsService.getNewsInfoByCode (newsCode);
/ / Go to the update page
return "to_updateNewsInfo";
}

public NewsDTO getModel () {
if (newsInfo! = null) {
newsInfo = new NewsDTO ();
}
return newsInfo;
}

public NewsDTO getNewsInfo () {
return newsInfo;
}

public void setNewsInfo (NewsDTO newsInfo) {
this.newsInfo = newsInfo;
}

public void setNewsService (NewsServiceImpl newsService) {
this.newsService = newsService;
}
}


struts.xml code




method = "showAllNewInfo">

. / back / news / showAllNewsInfo.jsp




method = "showNewInfo">

/ back / news / showNewsInfo.jsp


/ back / news / doModifyNews.jsp




method = "doInsertNewInfo">

.. /.. / back / news / showAllNewsInfo.jsp

/ back / news / doAddNews.jsp



method = "doDelNewInfo">

. / back / news / showAllNewsInfo.jsp




method = "doModifyNewInfo">
true

.. /.. / back / news / showAllNewsInfo.jsp

/ back / news / doModifyNews.jsp






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  This reply was moderator deleted at 2012-07-12 14:08:21

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code above getModel () method code is wrong :
if (newsinfo! = null) {
....
}
should read:
if (newsinfo == null) {
....
}

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estimated landlord would have solved the problem, but did not answer here . . . .
I also encountered the same problem , check the next , it seems that the landlord needs to be changed in struts.xml in refreshModelBeforeResult modelDriven.refreshModelBeforeResult. Like this:

<interceptor-ref name="defaultStack">
  					<param name="modelDriven.refreshModelBeforeResult">true</param>
  				</interceptor-ref>

should be fine
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If you have not read the children's shoes , you can look here :
http://unmi.cc/struts2-how-to-override-interceptor-parameters