I think I've read every question and answer on Spring and autowiring a servlet, both here and at springsource.org, and I still can't get it working.
All I want to do is have the datasource automatically set in my servlets. I understand that the container creates the servlet and not Spring.
Here is code from my test servlet:
package mypackage.servlets;
imports go here...
#Service
public class TestServlet extends HttpServlet
{
private JdbcTemplate _jt;
#Autowired
public void setDataSource(DataSource dataSource)
{
_jt = new JdbcTemplate(dataSource);
}
etc etc
In my applicationContext.xml I have:
<context:annotation-config />
<context:component-scan base-package="mypackage.servlets />
<import resource="datasource.xml" />
and in my datasource.xml:
<jee:jndi-lookup id="dataSource" jndi-name="java:comp/env/jdbc/db" />
If I can't get this working I'll just use WebApplicationContextUtils in the servlet's init method but I'd really like to make this work after all the reading I've been doing.
I'm using Spring 3, Java 1.6.
Thanks,
Paul
You need to replace your Servlets by Spring MVC contollers. Because Spring will not inject anything the classes (servlets) created by someone else then Spring itselfe (except #Configurable).
(To get an very simple example, take a look at the STS Spring Template Project: MVC).
What I wanted to do was get a DataSource reference in my Servlet for free, i.e. not calling a static getDatasource method on some class.
Here's what I learned and how I got it working:
Servlets cannot be configured or autowired by Spring. Servlets are created before Spring's app context is loaded. See issue SPR-7801: https://jira.springsource.org/browse/SPR-7801
What I did was create a DataSource in my applicationContext.xml and export that as a property:
<jee:jndi-lookup id="dataSource" jndi-name="java:comp/env/jdbc/db" />
<bean class="org.springframework.web.context.support.ServletContextAttributeExporter">
<property name="attributes">
<map>
<entry key="myDatasource">
<ref bean="dataSource"/>
</entry>
</map>
</property>
</bean>
In my servlet's init method I read the property:
public void init(ServletConfig config)
{
Object obj = config.getServletContext().getAttribute("myDatasource");
setDataSource((DataSource)obj);
}
public void setDataSource(DataSource datasource)
{
// do something here with datasource, like
// store it or make a JdbcTemplate out of it
}
If I'd been using DAOs instead of hitting the database from the servlets it would have been easy to wire them up for #Autowired by marking them #Configurable, and also be able to use #Transactional and other Spring goodies.
Related
Secton 65.3 of the spring boot manual indicates that I can replace the default ObjectMapper by providing my own. I am not using boot, just a spring WebMVC application that builds to a .war and runs in tomcat.
It instantiates my ObjectMapper but doesn't use it. I used the debugger to trace through why timestamps still come out as numeric and found that it was using a different instance of ObjectMapper. It's not clear to me where it came from, or why this doesn't cause it to only use mine:
#Primary
#Bean
public ObjectMapper localObjectMapper() {
JodaMapper mapper = new JodaMapper();
mapper.setWriteDatesAsTimestamps(false);
mapper.getSerializationConfig().with(SerializationFeature.INDENT_OUTPUT)
.without(SerializationFeature.WRITE_DURATIONS_AS_TIMESTAMPS)
.without(SerializationFeature.WRITE_DATE_KEYS_AS_TIMESTAMPS)
.without(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
return mapper;
}
The above is in a #Configure bean that's definitely getting loaded.
The approach I took above worked fine in Spring 3, just not when I ugpraded to 4.2.2. I have read Jackson Integration Improvements as well, and tried approaches listed there, to the same effect.
--Chris
The way I always did it was:
#Configuration
#EnableWebMvc
public class MyWebMvcConfigurer extends WebMvcConfigurerAdapter {
#Bean
public ObjectMapper localObjectMapper() {
JodaMapper mapper = new JodaMapper();
// ...
return mapper;
}
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(new MappingJackson2HttpMessageConverter (localObjectMapper())); // use your own ObjectMapper
}
}
One warning, to quote the JavaDoc of WebMvcConfigurer.html#configureMessageConverters:
Note that adding converters to the list, turns off default converter registration. To simply add a converter without impacting default registration, consider using the method extendMessageConverters(java.util.List) instead.
In Spring 4 I've solved with the following xml-configuration
<bean name="jacksonObjectMapper"
class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="featuresToDisable">
<array>
<util:constant
static-field="com.fasterxml.jackson.databind.SerializationFeature.WRITE_DATES_AS_TIMESTAMPS" />
</array>
</property>
</bean>
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean
class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper" ref="jacksonObjectMapper" />
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
putting it in the Servlet configuration file, usually under
/WEB-INF/spring/appServlet/*.xml
I testing my DAO, but it didn't work. The following error occurs:
Tests in error:
testAccountOperations(com.tsekhan.rssreader.dao.HibernateControllerTest): Error creating bean with name 'com.tsekhan.rssreader.dao.HibernateControllerTest': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.tsekhan.rssreader.dao.HibernateController com.tsekhan.rssreader.dao.HibernateControllerTest.hibernateController; nested exception is java.lang.IllegalArgumentException: Can not set com.tsekhan.rssreader.dao.HibernateController field com.tsekhan.rssreader.dao.HibernateControllerTest.hibernateController to $Proxy25
My DAO:
#Service
#Scope("singleton")
public class HibernateController extends HibernateDaoSupport {
#Autowired
public SessionFactory sessionFactory;
#Transactional
public void addAcount(Account account) {
sessionFactory.getCurrentSession().saveOrUpdate(account);
}
}
My test for this DAO:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration("classpath:/applicationContext.xml")
public class HibernateControllerTest {
#Autowired
HibernateController hibernateController;
private Set<Channel> getTestChannelList(String channelLink) {
Channel testChannel = new Channel();
testChannel.setSourceLink(channelLink);
Set<Channel> testChannelList = new HashSet<Channel>();
testChannelList.add(testChannel);
return testChannelList;
}
private Account getTestAccount(String accountLogin, String channelLink) {
Account testAccount = new Account();
testAccount.setAccountLogin(accountLogin);
testAccount.setChannelList(getTestChannelList(channelLink));
return testAccount;
}
#Test
public void testAccountOperations() {
hibernateController
.addAcount(getTestAccount("test_login", "test_link"));
}
}
My applicationContext.xml:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd"
default-autowire="byName">
<!-- Enabling spring-transaction annotations -->
<tx:annotation-driven transaction-manager="transactionManager"/>
<!-- Enabling annotation-driven configurating -->
<context:annotation-config />
<!-- Creation of transaction manager -->
<bean id="transactionManager" scope="singleton"
class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
<bean id="sessionFactory" scope="singleton"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="configLocation" value="classpath:/hibernate.cfg.xml"/>
<property name="configurationClass">
<value>org.hibernate.cfg.AnnotationConfiguration</value>
</property>
</bean>
<!--
A Spring interceptor that takes care of Hibernate session lifecycle.
-->
<bean id="hibernateInterceptor"
class="org.springframework.orm.hibernate3.HibernateInterceptor">
<property name="sessionFactory">
<ref bean="sessionFactory"/>
</property>
</bean>
<bean name="employeeDAO" scope="prototype"
class="com.tsekhan.rssreader.dao.HibernateController" />
<!-- Searching for hibernate POJO files in package com.tsekhan.rssreader.web -->
<context:component-scan base-package="com.tsekhan.rssreader.web" />
<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
</beans>
I note, that if you comment #Transactional in DAO, bean is created correctly. What happens?
First of all its realy bad to give name ending in Controller to a DAO its very confusing, Controller and DAO have all together different purpose.
When you add #Transactional to a service or dao class, for spring to make it work in a transaction needs to create a proxy of that class, its a kind of wrapper where in before the execution of proxied class(class in consideration which is proxied) method spring starts the transaction and after the execution in case no exceptions completes the transaction, this can be done in spring via AOP and Annotations. To describe in code.
public class OriginalDaoImpl implements OriginalDao extends DaoSupport {
public void save(Object o){
manager.save(o);
}
}
public class ProxyDaoImpl implements OriginalDao {
private OriginalDao originalDaoImpl; //instance of OriginalDaoImpl
public void save(Object o){
try{
transaction.start();
originalDaoImpl.save(o);
transaction.commit();
}catch(Exception e){
transaction.rollback();
}finally{
//clean up code
}
}
}
As you see this is not an exact implementation but a foundation code, how transaction magically works for you. The key point is there interface OriginalDao which makes this injection easy as OriginalDaoImpl and ProxyDaoImpl both implement same interface. Hence they can be swapped i.e. proxy taking place of original. This dynamic proxy can be created in java by Java dynamic proxy. Now, the question what if your class is not implementing an interface, it gets harder for the replacement to happen.
One of the libraries CGLIB as far as I know, helps in such a scenario, whereby it generates a dynamic subclass for the class in consideration and in overriden method performs the magic as described above, by calling super.save(o) to delegate to original code.
Now to the problem of injection.
Create interface and make your dao implement that and spring will default to JDK proxy as it is behaving now.
Add proxy-target-class="true" attribute to <tx:annotation-driven transaction-manager="transactionManager"/>
As far as exception is concerned it is throwing as it is expecting injected bean to be of type 'HibernateController' but its not.
For you reference you can refer links below.
10.5.6 Using #Transactional
Spring AOP Doc
Hope this helps !!!!!.
If your are using Spring MVC make sure to scan specific controller classes alone in servlet context file. Otherwise it will scan 2 times and transaction is not available on the application context.
I currently load my properties file like so in spring
<context:property-placeholder location="test-esb-project-config.properties"/>
<context:property-placeholder location="esb-project-config.properties"/>
This seems to work great for properties use inside the xml files. How do I load a property from inside my java code now though? OR how do I inject some kind of Bundle or Config object so I don't have to inject 10 properties in one bean?
thanks,
Dean
using annotations #Value(${property}) worked much better and it injected the property into my bean without all the work of xml typing and adding a setter...way too much work going that route.
You can either have setters for each property and wire them with the property reference.
public class MyBean{
public void setFoo(String foo){ /* etc */}
public void setBar(String bar){ /* etc */}
}
<bean class="foo.bar.MyBean">
<property name="foo" value="${my.properties.foo}" />
<property name="bar" value="${my.properties.bar}" />
</bean>
Or you can inject a Properties Object into your Spring Bean.
public class MyBean{
public void setProperties(Properties properties){
// init your properties here
}
}
<bean class="foo.bar.MyBean">
<property name="properties" value="classpath:/path.to.properties" />
</bean>
Both of these would also work without XML when using the #Value annotation.
(see Expression Language > Annotation-based Configuration)
I've been struggling with a configuration which requires a knowledge in AOP.
i must admit that AOP is that part i'm trying to get for a while without success.
It seems that my shiro annotations are not scanned and thus are ignored.
i've tried using shiro 1.1.0+ maven3+spring 3.0.5.RELEASE, hibernate 3.6.1.Final with ZK 5.0.6.
i got my hibernaterealm working , talking to database, i got the authentication working, i successfully(i believe) get the roles and permission loaded.
so to test the authorization side i have somewhere in my code this :
Subject currentUser = SecurityUtils.getSubject();
if (!currentUser.isPermitted("businessaccount:list")) {
throw new AuthorizationException("User not authorized");
}
and it works fine.
So i know my permissions were loaded.i'll be convenient for me using annotations to i've put it in implementation class, because i didn't plan on using interface at first place with my controller classes which are extending ZK GenericForwardController.
i've seen this bug and i've decided to do a try with one interface with the #RequiresPersmissions on methods.
apparently it's still not working as in it's giving access to unauthorized subject.there is no error in my log.Maybe i'm doing something wrong here are snippet of the codes:
#Component("layouteventhandler")
public class LayoutEventHandlerImpl extends GenericForwardComposer implements LayoutEventHandler {
Logger logger = Logger.getLogger(LayoutEventHandlerImpl.class);
Menuitem logout;
//...
#Override
public void onClick$pAccounts() {
try {
execution.sendRedirect("/accounts/personal/list");
} catch (Exception ex) {
logger.info("Error redirecting to personal accounts", ex);
}
}
#Override
public void onClick$bAccounts() {
try {
execution.sendRedirect("/accounts/business/list");
} catch (Exception ex) {
logger.info("Error redirecting to business accounts", ex);
}
}
//.....
}
its interface it :
public interface LayoutEventHandler {
#RequiresPermissions(value="personalaccount:list")
public void onClick$pAccounts();
#RequiresPermissions(value="businessaccount:list")
public void onClick$bAccounts();
//.....
}
here is my shiro applicationcontext
<bean id="hibernateRealm" class="com.personal.project.admin.webapp.security.DatabaseRealm" />
<bean id="securityManager" class="org.apache.shiro.web.mgt.DefaultWebSecurityManager">
<property name="realm" ref="hibernateRealm" />
</bean>
<bean id="lifecycleBeanPostProcessor" class="org.apache.shiro.spring.LifecycleBeanPostProcessor" />
<bean class="org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator"
depends-on="lifecycleBeanPostProcessor">
<!-- <property name="proxyTargetClass" value="true" />-->
</bean>
<bean class="org.apache.shiro.spring.security.interceptor.AuthorizationAttributeSourceAdvisor">
<property name="securityManager" ref="securityManager"/>
</bean>
<!-- Secure Spring remoting: Ensure any Spring Remoting method invocations can be associated
with a Subject for security checks. -->
<bean id="secureRemoteInvocationExecutor" class="org.apache.shiro.spring.remoting.SecureRemoteInvocationExecutor">
<property name="securityManager" ref="securityManager"/>
</bean>
<!-- ... -->
is it in there something that i should do? thanks for reading and helping out
I don't know Shiro, but I'm guessing that you've put annotations on your bean classes which implement interfaces and then you're proxying them for security, transactions, and/or something else. When that happens, the object that's returned is a JDK dynamic proxy, which isn't an instance of your bean's concrete class, only of the interface it implements. Therefore any annotation scanning that depends on annotations in the concrete class won't find them.
To expand on Ryan Stewart's answer, you need to add
#Scope(proxyMode = ScopedProxyMode.TARGET_CLASS)
to the implementing class (not the interface) and move the Shiro annotations to it.
I encountered a similar problem when I was running two spring contexts. There is a parent root context that defined Database, Service, Security and non-SpringMVC web beans and a child web context for a Spring MVC REST api which contained the Controllers I want to proxy. The Configuration for each context was class path scanning separate packages.
In this case make sure that the DefaultAdvisorAutoProxyCreator and the AuthorizationAttributeSourceAdvisor beans that are requied are defined in the child web context (i.e. where the Rest Controllers are class path scanned) as defining them in the parent context does not work (the documentation on the DefaultAdvisorAutoProxyCreate is quite clear about this in hindsight!).
Posting this in case someone else encounters the same issue.
My application data access layer is built using Spring and EclipseLink and I am currently trying to implement the following feature - Ability to switch the current/active persistence unit dynamically for a user. I tried various options and finally ended up doing the following.
In the persistence.xml, declare multiple PUs. Create a class with as many EntityManagerFactory attributes as there are PUs defined. This will act as a factory and return the appropriate EntityManager based on my logic
public class MyEntityManagerFactory {
#PersistenceUnit(unitName="PU_1")
private EntityManagerFactory emf1;
#PersistenceUnit(unitName="PU_2")
private EntityManagerFactory emf2;
public EntityManager getEntityManager(int releaseId) {
// Logic goes here to return the appropriate entityManeger
}
}
My spring-beans xml looks like this..
<!-- First persistence unit -->
<bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="emFactory1">
<property name="persistenceUnitName" value="PU_1" />
</bean>
<bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager1">
<property name="entityManagerFactory" ref="emFactory1"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager1"/>
The above section is repeated for the second PU (with names like emFactory2, transactionManager2 etc).
I am a JPA newbie and I know that this is not the best solution. I appreciate any assistance in implementing this requirement in a better/elegant way!
Thanks!
First of all thanks to user332768 and bert. I tried using AbstractRoutingDataSource as mentioned in the link provided by bert, but got lost trying to hook up my jpa layer (eclipselink). I reverted to my older approach with some modifications. The solution looks cleaner (IMHO) and is working fine. (switching database at runtime and also writing to multiple databases in the same transaction)
public class MyEntityManagerFactoryImpl implements MyEntityManagerFactory, ApplicationContextAware {
private HashMap<String, EntityManagerFactory> emFactoryMap;
public EntityManager getEntityManager(String releaseId) {
return SharedEntityManagerCreator.createSharedEntityManager(emFactoryMap.get(releaseName));
}
#Override
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
Map<String, LocalContainerEntityManagerFactoryBean> emMap = applicationContext.getBeansOfType(LocalContainerEntityManagerFactoryBean.class);
Set<String> keys = emMap.keySet();
EntityManagerFactory entityManagerFactory = null;
String releaseId = null;
emFactoryMap = new HashMap<String, EntityManagerFactory>();
for (String key:keys) {
releaseId = key.split("_")[1];
entityManagerFactory = emMap.get(key).getObject();
emFactoryMap.put(releaseId, entityManagerFactory);
}
}
}
I now inject my DAO's with an instance (singleton) of MyEntityManagerFactoryImpl. The dao will then simply call createSharedEntityManager with the required release and will get the correct EntityManager for that database. (Note that i am now using application managed EntityManager and hence i have to explicitly close them in my dao)
I also moved to jta transaction manager (to manage transaction across multiple databases)
This is how my spring xml looks like now.
...
<bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="em_Rel1">
<property name="persistenceUnitName" value="PU1" />
</bean>
<bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="em_Rel2">
<property name="persistenceUnitName" value="PU2" />
</bean>
<bean class="org.springframework.transaction.jta.JtaTransactionManager" id="jtaTransactionManager">
</bean>
<tx:annotation-driven transaction-manager="jtaTransactionManager"/>
....
Cheers! (comments are welcome)
I am not sure if this is a clean method. Instead of declaring the enitiymanagerfactory multiple times, we can use the spring application context to get the entitymanagerfactory declared in the spring application.xml.
hm = applicationContext.getBeansOfType(org.springframework.orm.jpa.LocalEntityManagerFactoryBean.class);
EntityManagerFactory emf = ((org.springframework.orm.jpa.LocalEntityManagerFactoryBean) hm.get("&emf1")).getNativeEntityManagerFactory();
EntityManagerFactory emf2 = ((org.springframework.orm.jpa.LocalEntityManagerFactoryBean) hm.get("&emf2")).getNativeEntityManagerFactory();
This is something i need to do in the future too, for this i have bookmarked Spring DynamicDatasourceRouting
http://blog.springsource.com/2007/01/23/dynamic-datasource-routing/
As far as i understand, this is using one PU, which gets assigned different DataSources. Perhaps it is helpful.