I am developing a web application using spring MVC. I just want a simple example of how to do session management in this. I have seen lot of forums but I am not able to get a clear picture of this
My requirement is
I have an object, which I would like to be accessible in all controllers and JSP's I
would like to set that in the controller and get that in JSP
I am looking for something like
Session.setAtribute();
Could you please let me know a very simple instance . Thank you
There are different ways of accessing servlet session in Spring MVC. But I think this one is the one that best suits your problem. You can create a session scoped bean, which holds your desired info:
#Component("myObjectHolder")
#Scope(WebApplicationContext.SCOPE_SESSION)
public class MyObjectHolderImpl implements MyObjectHolder {
private long userId;
private String username;
private Theme theme;
// Getters & Setter
}
Then, you can access to it from other beans:
#Controller
public class MyController {
#Autowired private MyObjectHolder myObjectHolder;
#RequestMapping
public ModelAndView switchTheme(String themeId) {
...
Theme newTheme = themeService.get(themeId);
myObjectHolder.setTheme(newTheme);
...
}
}
You can access directly from your view too, but you must configure it:
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
...
<property name="exposedContextBeanNames" value="myObjectHolder" />
</bean>
And in your JSP:
Hi ${myObjectHolder.username}, you switched
application theme to ${myObjectHolder.theme.name}
The simplest approach is to access HttpSession directly by injecting it into your handler method:
#RequestMapping("/page")
public ModelAndView page(HttpSession session) {
session.getAttribute("foo");
}
Related
I have a spring mvc 3.0 web application and am using a conversion-service as follows...
<bean id="applicationConversionService"
class="com.myer.reporting.converter.ApplicationConversionServiceFactoryBean"/>
<context:component-scan base-package="com.myer.reporting.controller" />
<context:component-scan base-package="com.myer.reporting.manager" />
<context:component-scan base-package="com.myer.reporting.dao"/>
<context:component-scan base-package="com.myer.reporting.dao.mapper"/>
<mvc:annotation-driven conversion-service="applicationConversionService"/>
In my controllers when i use the conversion service it all works fine.
#Autowired
private ApplicationConversionServiceFactoryBean applicationConversionService; '
But for the first time I am now trying to use the applicationConversionService in my mapper using the same method but the applicationConversionService is always coming back as null.
package com.myer.reporting.dao.mapper;
public class ImportHistoryRowMapper implements RowMapper<ImportHistory> {
private static final String BUSINESS_DATE = "businessdate";
private static final String TOTAL_TRAN_COUNT = "total_tran_count";
#Autowired
private ApplicationConversionServiceFactoryBean applicationConversionService;
public ImportHistory mapRow(ResultSet rs, int rowNum) throws SQLException {
Date businessDate = rs.getDate(BUSINESS_DATE);
Integer totalTranCount = rs.getInt(TOTAL_TRAN_COUNT);
ImportHistory importHistory = new ImportHistory();
importHistory.setBusinessDate(businessDate);
importHistory.setTransactionCount(totalTranCount);
// status
TrafficLightStatus status =
applicationConversionService.
getImportThresholdToStatusConverter()
.convert(totalTranCount);
importHistory.setStatus(status);
return importHistory;
}
}
I tried to add #Component to the top of the class but that doesn't seem to work either. I think I am lacking some understanding of the #Autowired annotation and therefore can't get this to work.
Can someone give me some advice on this please.
thanks
You need to make the ImportHistoryRowMapper spring managed for this to work.
I believe your dao class making the reference to this mapper class is singleton. For every request (i.e., call to method getJdbcTemplate().query ( sql, object array, new instance of ImportHistoryRowMapper);), you need to create new instance of ImportHistoryRowMapper i.e., it should be prototype.
You can inject prototype bean into singleton in 2 ways:
1) Lookup Method injection
2) Scoped proxies
Take a look at this.
I am trying to do a simple android application that communicates with a Spring server.
I'd like to use Sessions to store data of each logged in User.
My App exchange Json objects with the server and the Request Mapping is like this:
#Controller
public class LoginController {
#Autowired
private IUserDao userDao;
#RequestMapping( value = "/loginJson",method = RequestMethod.POST)
public #ResponseBody loginResponse login(#RequestBody loginModel login) {
loginResponse response=userDao.checkCredentials(login.getUsername(),login.getPassword());
System.out.println("Result="+response.isSuccess());
System.out.println("Received:"+login.getUsername()+" "+login.getPassword());
return response;
}
}
The controller is working fine, but I can't figure out how to store a sessione variable. I found many documents explaining Spring Sessions, but each of them different from the other.
Someone can suggest me some simple way to do this or some kind of good tutorial?
Not sure what you mean by saying Spring session, but you can declare additional HttpSession parameter in your method, and then do whatever you like inside of the method. Is this what you wanted to find out?
We are using Struts2-Spring integration and all my action classes implement SessionAware, sample code to action class and their spring definition is given below,
public class IRXxxxAction extends ActionSupport implements SessionAware {
private Map session;
public String execute()
{//}
public void setSession(Map<String, Object> session)
{
this.session = session;
}
}
Spring Configuration
<bean name="userAction" class="com.IRXxxxAction" >
<property name="adminDAO" ref="adminDAO" />
</bean>
If I understand correctly, each auto-wired property will be a singleton, so if the above is true, is there anyway that the session map get shared between two simultaneous requests?
Regards,
Ayush
You have asked same question on the user mailing list and as said if you are using Struts2-Spring plugin make sure to put bean scope as prototype.
Struts2 create new instance of action on each request, since action work as a model also and in order to make it thread safe a new object is being created on each request and placed on value stack.
Not proving scope will be treated by Spring as singleton and for ever request same action instance will be given back which can leads to a lot of issue from data corruption to weird behavior.
I have requirement for spring mvc 3 caching. Requirement is : while starting the server, we need to call database for one dropdown and put those values in the cache. So that whenever we required those values, we need to retrieve from cache.
Please help me with an example.
Thanks in advance.
May be you can use init-method (Spring 2.5) or #PostConstruct annotation (in Spring 3.0).
This method will be called during server start up
The following is code snippet
#Component
public class CacheDBData {
private String values[];
//add setter & getter
//This will be called during server start up after properties are initialised
#PostConstruct
public void getDataFromDB() {
values = //Logic to get data from DB and store that in values property
}
}
Suppose for example you can use in class as follows
#controller
public class HomeController {
#Autowired
private CacheDBData cacheDBData ;
//getter and setters
private void methodxyz() {
String values[] = cacheDBData.getValues();
}
}
I've had success with Ehcahe for Spring. There's a couple of config files to setup but after that you simply annotate the methods you want to cache the output from and it just works.
This has the advantage that you can change the values coming back from the service/database and NOT have to restart your app, unlike the accepted answer.
Story
I have a select control that represents user access level. I'm looking for a way to internationalize it. The label should be loaded from a message resource and the value should be used as is. I prepare all my drop down lists in controllers using a simple SelectOption class that has a label and a value properties. This way, my select's look consistent accross all jsp's.
Problem
I've found some examples but they are based on logic within jsp. Developer loops through his labels and manually constructs the option tag using a message resource. While this works, there just has to be a better way. I've also found some comments that Spring 3 will have support for internationalizing option labels but I can't find anything concrete on that.
Controller logic
Collection<SelectOption> optionList = new ArrayList<SelectOption>();
optionList.add(new SelectOption("-SELECT-", "-"));
optionList.add(new SelectOption("Administrator", "ADMIN"));
optionList.add(new SelectOption("Editor", "EDIT"));
bean.setFilterUserAccessLevelOptionList(optionList);
JSP logic
<form:select path="filterUserAccessLevel" items="${bean.filterUserAccessLevelOptionList}" itemLabel="label" itemValue="value"/>
Questions
I would like to add options in my controller in this way: optionList.add(new SelectOption("userAccessLevelAdministratorLabel", "ADMIN")); and have Spring convert userAccessLevelAdministratorLabel to a value from a message resource. Is this possible?
If Spring 3 cannot do this for me, how else can this be achieved without manually constructing the option tag within jsp?
=== 2012-01-15 ==============================================================
Still trying to work out a solution using aweigold's idea.
Controller
#Controller
public class UserController {
#Autowired
private UserService userService;
#Autowired
SelectOptionListBuilder listBuilder;
#RequestMapping("/userIndex/{pageNumber}")
public ModelAndView getUserList(#PathVariable Integer pageNumber, #ModelAttribute("userIndexBean") UserIndexBean phantomBean, Locale locale, Model model) {
UserIndexBean bean = new UserIndexBean();
// prepare filter form
Collection<SelectOption> optionList = listBuilder.getUserAccessLevelOptionList(true, SortOrder.NONE, locale);
bean.setFilterUserAccessLevelOptionList(optionList);
SelectOptionListBuilderImpl
#Component
public class SelectOptionListBuilderImpl implements SelectOptionListBuilder, MessageSourceAware {
private MessageSource messageSource;
#Override
public void setMessageSource(MessageSource messageSource) {
this.messageSource = messageSource;
}
#Override
public List<SelectOption> getUserAccessLevelOptionList(boolean addSelectPrompt, SortOrder sortOrder, Locale locale) {
List<SelectOption> optionList = new ArrayList<SelectOption>();
if(addSelectPrompt) {
optionList.add(new SelectOption(messageSource.getMessage("common.selectPromptLabel", null, locale), "-"));
}
messageSource mapping
<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
<property name="basename" value="/WEB-INF/i18n/messages" />
<property name="defaultEncoding" value="UTF-8"/>
<property name="UseCodeAsDefaultMessage" value="true"/>
</bean>
Exception
org.springframework.context.NoSuchMessageException: No message found under code 'common.selectPromptLabel' for locale 'en_CA'
When I need to do operations like this in a Controller outside of a jsp, I've been making my Controllers MessageSourceAware. Spring will then inject a new MessageSource when they are swapped, and you can interrogate it much like Spring does. In your example, you would do something like this:
#Controller
public class someController implements MessageSourceAware {
private MessageSource messageSource;
#Override
public void setMessageSource(MessageSource messageSource) {
this.messageSource = messageSource;
}
#RequestMapping
// Pass in the locale from the LocaleResolver
public void someMapping(Locale locale){
optionList.add(new SelectOption(
messageSource.getMessage("userAccessLevelAdministratorLabel", null, locale),
"ADMIN"))
}
}
Have a look at a spring roo project. They managed this kind of problem by creating tagx tags. This tags do what you already descibed (it contains a litte logic to load the messages from ressources and build the option tags). But because the logic is witten once and you can use this tags like normal tags in you jspx files, it feels like a tag that do what you want to have.