I have a Spring Bean defined in my applicationContext like:
<bean id="spaceReader" class="com.company.SpaceReader">
</bean>
I would like to be able to access this bean in my Application Servlet without having to use:
ApplicationContext context = new ClassPathXmlApplicationContext(CONTEXT_LOCATION);
context.getBean("SpaceReader");
I've tried exporting it using the following:
<bean id="ContextExporter" class="org.springframework.web.context.support.ServletContextAttributeExporter">
<property name="contextExporterAttributes">
<map>
<entry key="SpaceReaderKey">
<ref local="spaceReader" />
</entry>
</map>
</property>
</bean>
but when i inject it into the Servlet, it returns a Null value. Just wondering if there's something i'm missing when i export the Bean or when i try to access it in the Servlet?
You can inject dependencies using annotations even in servlet (there is a special SpringBeanAutowiringSupport helper class for this pourpose):
public class CustomServlet extends HttpServlet {
#Autowired
private ProductService productService;
#Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
// inject productService dependency
SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);
}
....
}
Related
I'm new to Spring development.And right now,i'm really facing a problem.Here are the code snippets to make you realize my problem clearly.............
Here is my DAO class:
public class LoginDaoImpl {
private DataSource dataSource;
private JdbcTemplate jdbcTemplate;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
public int checkLoginDetails(LoginVo loginVo){
String sql = "select count(*) from empsctygrp where username=? and password=?";
jdbcTemplate = new JdbcTemplate(dataSource);
int count = jdbcTemplate.queryForObject(sql,new Object[]{loginVo.getUserName(),loginVo.getPassword()},Integer.class);
return count;
}
}
Now here is my Business-Object(BO) class:
public class LoginBo {
LoginDaoImpl loginDaoImpl = new LoginDaoImpl();
public int checkLoginDetails(LoginVo loginVo){
return loginDaoImpl.checkLoginDetails(loginVo);
}
}
Now,here is my dispatcher-servlet xml code:
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/>
<property name="url" value="jdbc:oracle:thin:#117.194.83.9:1521:XE"/>
<property name="username" value="system"/>
<property name="password" value="password1$"/>
</bean>
<bean id="loginDaoImpl" class="com.abhinabyte.dao.LoginDaoImpl">
<property name="dataSource" ref="dataSource" />
</bean>
Now whenever i'm trying to run this on server the following exception is given:
SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/A] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required] with root cause
java.lang.IllegalArgumentException: Property 'dataSource' is required
Please help me solve this problem.............:(
Try this in LoginBo class:
#Autowired
LoginDaoImpl loginDaoImpl;
instead of
LoginDaoImpl loginDaoImpl = new LoginDaoImpl();
The problem is that you manually instantiate LoginDaoImpl.
I was having the same problem and could not find a comprehensive answer on the web, so I decided to post one here for anyone else, or for future me.
I'm still learning so if you think I have made a mistake below, please feel free to edit.
Summary:
Include <integration:annotation-config/> <context:component-scan base-package="myproject"/> in your servlet to pick up annotations
Configure JUnit tests with #RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration("file:WEB-INF/FinanceImportTool-servlet.xml")
Don't autowire dataSource or jdbcTemplate if these fields are already provided by a parent class e.g. StoredProcedure
Don't use new() as this initializes classes outside the applicationContext
Beware of using properties in your constructor which have not yet been set - obvious but embarrassingly easy to do
My original class (now altered):
public class MyDAOImpl extends StoredProcedure implements MyDAO {
private static final String SPROC_NAME = "dbo.MySP";
public MyDAOImpl(DataSource dataSource) {
super(dataSource, SPROC_NAME);
// ...declared parameters...
compile();
}
}
MyProject-servlet.xml file (only relevant bits included):
<!-- Used by Spring to pick up annotations -->
<integration:annotation-config/>
<context:component-scan base-package="myproject"/>
<bean id="MyDAOBean" class="myproject.dao.MyDAOImpl" >
<constructor-arg name="dataSource" ref="myDataSource"/>
</bean>
<!-- properties stored in a separate file -->
<bean id="myDataSource" class="com.microsoft.sqlserver.jdbc.SQLServerDataSource">
<property name="databaseName" value="${myDataSource.dbname}" />
<property name="serverName" value="${myDataSource.svrname}" />
<!-- also loaded portNumber, user, password, selectMethod -->
</bean>
Error: property 'dataSource' is required, or NullPointerException (1)
Other answers say make sure you have passed dataSource as a <property> for your bean in the servlet, etc.
I think #Abhinabyte the OP needed to annotate his setDataSource() method with #Annotation, and use <integration:annotation-config/> <context:component-scan base-package="myproject"/> in his servlet to successfully pass in dataSource as a dependency to LoginDaoImpl.
In my case, I tried adding 'dataSource' as a property and autowiring it. The "dataSource is required" error message became a NullPointerException error.
I realised after far too long that MyDAOImpl extends StoredProcedure.
dataSource was already a property of StoredProcedure. By having a dataSource property for MyDAOImpl, the autowiring was not picking up and setting the dataSource property of StoredProcedure, which left dataSource for StoredProcedure as null.
This was not picked up when I tested the value of MyDAOImpl.dataSource, as of course by now I had added a MyDAOImpl.dataSource field that had been autowired successfully. However the compile() method inherited from StoredProcedure used StoredProcedure.dataSource.
Therefore I didn't need public DataSource dataSource; property in MyDAOImpl class. I just needed to use the StoredProcedure constructor with super(dataSource, sql); in the constructor for MyDAOImpl.
I also didn't need a MyDAOImpl.jdbcTemplate property. It was set automatically by using the StoredProcedure(dataSource, sql) constructor.
Error: NullPointerException (2)
I had been using this constructor:
private static final String SPROC_NAME = "dbo.MySP";
public MyDAOImpl(DataSource dataSource) {
super(dataSource, SPROC_NAME);
}
This caused a NullPointerException because SPROC_NAME had not been initialized before it was used in the constructor (yes I know, rookie error). To solve this, I passed in sql as a constructor-arg in the servlet.
Error: [same error message appeared when I had changed file name]
The applicationContext was referring to the bin/ instances of my beans and classes. I had to delete bin/ and rebuild the project.
My new class:
public class MyDAOImpl extends StoredProcedure implements MyDAO {
#Autowired // Necessary to prevent error 'no default constructor found'
public MyDAOImpl(DataSource dataSource, String sql) {
super(dataSource, sql);
// ...declared parameters...
compile();
}
New MyProject-servlet.xml file (only relevant bits included):
<!-- Used by Spring to pick up annotations -->
<integration:annotation-config/>
<context:component-scan base-package="myproject"/>
<bean id="myDAOBean" class="org.gosh.financeimport.dao.MyDAOImpl" >
<constructor-arg name="dataSource" ref="reDataSource"/>
<constructor-arg name="sql" value="dbo.MySP" />
</bean>
<!-- properties stored in a separate file -->
<bean id="myDataSource" class="com.microsoft.sqlserver.jdbc.SQLServerDataSource">
<property name="databaseName" value="${myDataSource.dbname}" />
<property name="serverName" value="${myDataSource.svrname}" />
<!-- also loaded portNumber, user, password, selectMethod -->
</bean>
Helpful places:
If you can get past the rage, this answer on Spring forums might help too
This answer gives a broad introduction to Spring configuration
This answer has simple but useful suggestions
You should annotate that beans that will suffer IoC. Like
#Bean public class LoginDAOImpl { #Inject DataSource dataSource;......}
You set up in spring context this beans, but, you're not using them.
OBS:
When I use the JDBCTemplate I configure de IoC of JDBC like
<bean id="dataSourcePerfil" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${br.com.dao.jdbc.driver}" />
<property name="url" value="${br.com.dao.jdbc.url}" />
<property name="username" value="${br.com.dao.jdbc.user}" />
<property name="password" value="${br.com.dao.jdbc.pass}" />
</bean>
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<constructor-arg ref="dataSourcePerfil" />
</bean>
then.... after at all
#Bean
public class LoginDAOImpl {
#Autowired
private JdbcTemplate jdbcTemplate;
#Override
public List<ClienteReport> getClientes() {
return Collections<ClienteReport>. emptyList();
}
}
I have a web application based on Spring JDBC and Jersey RESTful web service. I'm using the following Spring JDBC template class to initiate the dataSource and execute an SQL script (update_condition_table.sql):
public class CustomerJDBCTemplate implements CustomerDAO {
private DataSource dataSource;
private JdbcTemplate jdbcTemplateObject;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
this.jdbcTemplateObject = new JdbcTemplate(dataSource);
Resource rc = new ClassPathResource("update_condition_table.sql");
JdbcTestUtils.executeSqlScript(jdbcTemplateObject, rc, false);
}
// ......other methods
}
The bean configuration file is beans.xml:
<!-- Initialization for data source -->
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/customer" />
<property name="username" value="root" />
<property name="password" value="mypassword" />
</bean>
<!-- Definition for customerJDBCTemplate bean -->
<bean id="customerJDBCTemplate" class="com.example.db.CustomerJDBCTemplate">
<property name="dataSource" ref="dataSource" />
</bean>
The Jersey controller class contains the instantiation of class CustomerJDBCTemplate and serves as the REST web service:
#Path("/customer")
public class CustomerService {
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
CustomerJDBCTemplate dbController = (CustomerJDBCTemplate) context.getBean("customerJDBCTemplate");
// ... some GET/POST methods
}
When I launched my web app by entering the index URL in the browser, the SQL script gets executed by the customerJDBCTemplate bean. However, when I clicked to navigate to other pages, it crashed and reported that the SQL script cannot be executed again. So obviously the SQL script was executed again after initialization of dataSource and initial launch of the index web page. How to avoid this by just running the SQL script only once upon initial startup of the web app?
Looks like I need to move the bean instantiate code out of CustomerService class, but where should I put that code?
I figured it out that I should set the bean application context to be static within CustomerService class and do it in the static initialization block as follows:
#Path("/customer")
public class CustomerService {
private static ApplicationContext context;
private static CustomerJDBCTemplate dbController;
static {
context = new ClassPathXmlApplicationContext("beans.xml");
dbController = (CustomerJDBCTemplate) context.getBean("customerJDBCTemplate");
}
//... other methods
}
I guess the reason is Jersey creates a different instance of CustomerService for each HTTP session (correct me if I'm wrong). So if I set the bean context as instance variable, it will do the initialization for every HTTP request.
Have your CustomerJDBCTemplate implement InitializingBean. afterPropertiesSet will get called once, right after all properties have been set by Spring's BeanFactory.
For example:
public class CustomerJDBCTemplate implements CustomerDAO, InitializingBean {
...
// ......other methods
public void afterPropertiesSet() throws Exception {
//do your initializing, or call your initializing methods
}
}
I'm trying to inject (autowire) a spring bean to an abstract class but it doesn't seem to work.
public abstract class BaseEntity {
#Autowired(required = true)
protected SecurityProvider securityService;
public BaseEntity() {
}
}
And the injected class:
#Component
public class SecurityService extends SecurityProviderImpl implements SecurityProvider {
#Autowired
public SecurityService(ICipherDescriptor cipherDescriptor) {
super(cipherDescriptor);
}
}
The SecurityService gets initialized just fine (I can see it while debugging) but the class that inherit from BaseEntity cannot use the injected SecurityService since it is null (doesn't get injected for some reason).
I tried doing it via XML as well, defining the BaseEntity as abstract:
<bean id="baseEntity" abstract="true" class="com.bs.dal.domain.BaseEntity">
<property name="securityService" ref="securityService"/>
</bean>
<bean id="securityService" class="com.bs.dal.secure.SecurityService">
<constructor-arg ref="cipherDescriptor" />
</bean>
but still with no success.
Where am I going wrong?
I think I know what's wrong here. I'm trying to inject a spring bean to an entity - which is impossible (unless you use aspectJ weaving) since the entities are not instantiated/managed by Spring. Make sense, isn't it?
If your BaseEntity is also instantiated by spring, you just need to add a parent attribute to the bean definition to link it to your BaseEntity definition like so:
<bean id="baseEntity" abstract="true" class="com.bs.dal.domain.BaseEntity">
<property name="securityService" ref="securityService"/>
</bean>
<bean id="derivedEntity" parent="baseEntity" class="com.bs.dal.domain.DerivedEntity"/>
<bean id="securityService" class="com.bs.dal.secure.SecurityService">
<constructor-arg ref="cipherDescriptor" />
</bean>
In short, the two key parts to such a definition are the abstract attribute on the parent class and the parent attribute on the subclass.
What is a good way to inject some file resource into Spring bean ?
Now i autowire ServletContext and use like below. Is more elegant way to do that in Spring MVC ?
#Controller
public class SomeController {
#Autowired
private ServletContext servletContext;
#RequestMapping("/texts")
public ModelAndView texts() {
InputStream in = servletContext.getResourceAsStream("/WEB-INF/file.txt");
// ...
}
}
Something like this:
#Controller
public class SomeController {
private Resource resource;
public void setResource(Resource resource) {
this.resource = resource;
}
#RequestMapping("/texts")
public ModelAndView texts() {
InputStream in = resource.getInputStream();
// ...
in.close();
}
}
In your bean definition:
<bean id="..." class="x.y.SomeController">
<property name="resource" value="/WEB-INF/file.txt"/>
</bean>
This will create a ServletContextResource using the /WEB-INF/file.txt path, and inject that into your controller.
Note you can't use component-scanning to detect your controller using this technique, you need an explicit bean definition.
Or just use the #Value annotation.
For single file:
#Value("classpath:conf/about.xml")
private Resource about;
For multiple files:
#Value("classpath*:conf/about.*")
private Resource[] abouts;
What do you intend to use the resource for? In you example you don't do anything with it.
From it's name, however, it looks like you are trying to load internationalisation / localisation messages - for which you can you a MessageSource.
If you define some beans (possibly in a separate messages-context.xml) similar to this:
<bean id="messageSource"
class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
<property name="basenames">
<list>
<value>WEB-INF/messages/messages</value>
</list>
</property>
</bean>
<bean id="localeChangeInterceptor"
class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
<property name="paramName" value="lang" />
</bean>
<bean id="localeResolver"
class="org.springframework.web.servlet.i18n.CookieLocaleResolver">
<property name="defaultLocale" value="en_GB" />
</bean>
Spring will load your resource bundle when you application starts. You can then autowire the MessageSource into your controller and use it to get localised messages:
#Controller
public class SomeController {
#Autowired
private MessageSource messageSource;
#RequestMapping("/texts")
public ModelAndView texts(Locale locale) {
String localisedMessage = messageSource.getMessage("my.message.key", new Object[]{}, locale)
/* do something with localised message here */
return new ModelAndView("texts");
}
}
NB. adding Locale as a parameter to your controller method will cause Spring to magically wire it in - that's all you need to do.
You can also then access the messages in your resource bundle in your JSPs using:
<spring:message code="my.message.key" />
Which is my preferred way to do it - just seems cleaner.
i am using quartz with spring
and i want to inject/use another class in the job class
and i don't know how to do it correctly
the xml:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<!-- Scheduler task -->
<bean name="schedulerTask" class="com.mkyong.quartz.SchedulerTask" />
<!-- Scheduler job -->
<bean name="schedulerJob"
class="org.springframework.scheduling.quartz.JobDetailBean">
<property name="jobClass" value="com.mkyong.quartz.SchedulerJob" />
<property name="jobDataAsMap">
<map>
<entry key="schedulerTask" value-ref="schedulerTask" />
</map>
</property>
</bean>
<!-- Cron Trigger -->
<bean id="cronTrigger"
class="org.springframework.scheduling.quartz.CronTriggerBean">
<property name="jobDetail" ref="schedulerJob" />
<property name="cronExpression" value="0/10 * * * * ?" />
</bean>
<!-- Scheduler -->
<bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
<property name="jobDetails">
<list>
<ref bean="schedulerJob" />
</list>
</property>
<property name="triggers">
<list>
<ref bean="cronTrigger" />
</list>
</property>
</bean>
</beans>
the quartz job:
package com.mkyong.quartz;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.springframework.scheduling.quartz.QuartzJobBean;
public class SchedulerJob extends QuartzJobBean
{
private SchedulerTask schedulerTask;
public void setSchedulerTask(SchedulerTask schedulerTask) {
this.schedulerTask = schedulerTask;
}
protected void executeInternal(JobExecutionContext context)
throws JobExecutionException {
schedulerTask.printSchedulerMessage();
}
}
the task to be executed:
package com.mkyong.quartz;
public class SchedulerTask {
public void printSchedulerMessage() {
System.out.println("Struts 2 + Spring + Quartz ......");
}
}
i want to inject another DTO class that deals with Database in the task class
to do some database work in the task, how to do that ?
In your solution you are using the spring #Autowired annotation in a class that is not instantiated by Spring. Your solution will still work if you remove the #Autowired annotation because Quartz is setting the property, not Spring.
Quartz will try to set every key within the JobDataMap as a property. E.g. since you have a key "myDao" Quartz will look for a method called "setMyDao" and pass the key's value into that method.
If you want Spring to inject spring beans into your jobs, create a SpringBeanJobFactory and set this into your SchedulerFactoryBean with the jobFactory property within your spring context.
SpringBeanJobFactory javadoc:
Applies scheduler context, job data map and trigger data map entries
as bean property values
Not sure if this is what you want, but you can pass some configuration values to the Quartz job. I believe in your case you could take advantage of the jobDataAsMap property you already set up, e.g.:
<property name="jobDataAsMap">
<map>
<entry key="schedulerTask" value-ref="schedulerTask" />
<entry key="param1" value="com.custom.package.ClassName"/>
</map>
</property>
Then you should be able to access it in your actual Java code in manual way:
protected void executeInternal(JobExecutionContext context) throws JobExecutionException {
schedulerTask.printSchedulerMessage();
System.out.println(context.getJobDetail().getJobDataMap().getString("param1"));
}
Or using the magic Spring approach - have the param1 property defined with getter/setter. You could try defining it with java.lang.Class type then and have the done automatically (Spring would do it for you):
private Class<?> param1;
// getter & setter
protected void executeInternal(JobExecutionContext context) throws JobExecutionException {
schedulerTask.printSchedulerMessage();
System.out.println("Class injected" + getParam1().getName());
}
I haven't tested it though.
ApplicationContext springContext =
WebApplicationContextUtils.getWebApplicationContext(
ContextLoaderListener.getCurrentWebApplicationContext().getServletContext()
);
Bean bean = (Bean) springContext.getBean("beanName");
bean.method();
As mentioned in inject bean reference into a Quartz job in Spring? you can use spring SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);
#Named
public class SampleJob implements Job {
#Inject
private AService aService;
#Override
public void execute(JobExecutionContext context)
throws JobExecutionException {
//Do injection with spring
SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);
aService.doIt();
}
}
As mentioned it may not wotk on some spring version but I have tested it on 4.2.1.RELEASE which worked fine.
this is my solution:
public class MySpringBeanJobFactory extends
org.springframework.scheduling.quartz.SpringBeanJobFactory implements
ApplicationContextAware {
private ApplicationContext ctx;
#Override
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
this.ctx = applicationContext;
}
#Override
protected Object createJobInstance(TriggerFiredBundle bundle)
throws Exception {
Object jobInstance = super.createJobInstance(bundle);
ctx.getAutowireCapableBeanFactory().autowireBean(jobInstance);
return jobInstance;
}
}
then config the class of MySpringBeanJobFactory in the xml：
<bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
<property name="jobFactory">
<bean class="com.xxxx.MySpringBeanJobFactory" />
</property>
<property name="configLocation" value="classpath:quartz.properties" />
<property name="triggers">
<list>
<ref bean="cronTrigger"/>
</list>
</property>
</bean>
Good luck ! :)