I am working on Spring 4 mvc and hibernate
I want to run code on the server startup that will use the get data from the database then do some business logic
where can I put my code I tried to put the code
org.springframework.web.servlet.support.AbstractDispatcherServletInitializer.onStartup(ServletContext)
but I was not able to use #Autowired variables
public class WebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
#Autowired
TaskDAO task;
#Override
protected Class<?>[] getRootConfigClasses() {
return new Class[] { SpringRootConfig.class };
}
#Override
protected Class<?>[] getServletConfigClasses() {
return new Class[] { SpringWebConfig.class };
}
#Override
protected String[] getServletMappings() {
return new String[] { "/" };
}
#Override
public void onStartup(ServletContext servletContext) throws ServletException {
task.getAllTasks()
// TODO Auto-generated method stub
super.onStartup(servletContext);
}
}
You are not able to autowire variables because your class is not managed by spring. So annotate your class with #Component annotation.
Then you can define a method that will do your logic (for example onStartup method) and annotate it with the #PostConstruct annotation as explained in this answers.
How to call a method after bean initialization is complete?
It will execute the method after the beans initialization.
This could be your class:
#Component
public class WebInitializer{
#Autowire
TaskDAO task;
#PostConstruct
private void onStartup(){
task.getAllTasks();
// Do whatever you want
}
}
Related
I have the following pseudo code:
#Bean
public List<BeanB> beanB(
List<BeanA> beansA) {
List<BeanB> beansB = new ArrayList<>();
for (BeanA beanA : beansA) {
beansB.add(new BeanB(beanA))
}
return beansB;
}
#Bean
public BeanC beanC(
List<BeanB> beansB) {
return new BeanC(beansB);
}
Now the challenge is when the list of BeansB is constructed post construct is not invoked on those beans in the list. Is there any idiomatic way to trigger post construct invocation on those beans.
This does not work well as #PostConstruct is called by Spring. and from your code, for List<BeanB>, Spring will only try to find #PostConstruct in List. If it can find it, it will execute the #PostConstruct code.
I suspect you are writing beanA as follow in case you have #PostConstruct in beanA's class like below.
#Bean
public BeanA beanA_1() {
return new BeanA();
}
#Bean
public BeanA beanA_2() {
return new BeanA();
}
// which naming List of Bean B as beanB does not seems a good idea though
#Bean
public List<BeanB> beanB(List<BeanA> beansA) {
List<BeanB> beansB = new ArrayList<>();
for (BeanA beanA : beansA) {
beansB.add(new BeanB(beanA))
}
return beansB;
}
To make it work, there are multiple ways, I will just suggests some of them.
Creating a new Class, says BeanBCollectionWrappe to wrap the List of BeanB. And to make the code a bit more robust, I am implementing InitializingBean instead of #PostConstruct which is essentially the same, but allow me to ensure the method is afterPropertiesSet but not any methods.
public class BeanBCollectionWrapper implements InitializingBean {
private List<BeanB> beansB;
public void afterPropertiesSet() throws Exception {
for (BeanB beanB: beansB) {
beanB.afterPropertiesSet();
}
}
// getter and setter
}
public class BeanB implements InitializingBean {
public void afterPropertiesSet() throws Exception {
// ...
}
}
The Wrapper code can definitely be a bit better by use of Generics, like replacing BeanB to <T extends InitializingBean>.
And for the last Part,
#Bean
public BeanC beanC(BeanBCollectionWrapper wrapper) {
return new BeanC(wrapper.getBeansB());
}
Another method can be done by implementing BeanPostProcessor.
For example,
#Component
public class BeanBListBeanPostProcessor implements BeanPostProcessor{
#Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
if (beanName.equals("beanB")) {
List<BeanB> beanBList = (List) bean;
for (BeanB beanB : beanBList) {
try {
beanB.afterPropertiesSet();
} catch (Exception exception) {
exception.printStackTrace();
}
}
}
return null;
}
}
public class BeanB implements InitializingBean {
public void afterPropertiesSet() throws Exception {
// ...
}
}
I am trying to create a Spring boot application with JFrame. I can see my beans in applicationContext but they are not getting autowired. I am unable to find the reason for this issue. Can someone help me with this?
Here is the code:
JavauiApplication - it is showing both userManager and userNameRepository is beans
#SpringBootApplication
public class JavauiApplication implements CommandLineRunner {
#Autowired
private ApplicationContext appContext;
public static void main(String[] args) {
new SpringApplicationBuilder(JavauiApplication.class).headless(false).run(args);
java.awt.EventQueue.invokeLater(() -> new InputNameForm().setVisible(true));
}
#Override
public void run(String... args) throws Exception {
String[] beans = appContext.getBeanDefinitionNames();
Arrays.sort(beans);
for (String bean : beans) {
System.out.println(bean);
}
}
}
InputNameForm.java -> userManager coming null
#Component
public class InputNameForm extends javax.swing.JFrame {
/**
* Creates new form InputNameForm
*/
public InputNameForm() {
initComponents();
}
#Autowired
UserManager userManager;
private void submitButtonActionPerformed(java.awt.event.ActionEvent evt) {
userManager.setName(firstName.getText(), lastName.getText());
}
/**
* #param args the command line arguments
*/
public static void main(String args[]) {
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(InputNameForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new InputNameForm().setVisible(true);
}
});
}
// Variables declaration - do not modify//GEN-BEGIN:variables
private javax.swing.JTextField firstName;
private javax.swing.JLabel firstNameLabel;
private javax.swing.JTextField lastName;
private javax.swing.JLabel lastNameLabel;
private javax.swing.JButton submitButton;
// End of variables declaration//GEN-END:variables
}
UserManager.java -> userNameRepository is coming null
#Component
public class UserManager {
#Autowired
UserNameRepository userNameRepository;
public void setName(String firstName, String lastName) {
userNameRepository.save(new UserName(firstName, lastName));
System.out.println(userNameRepository.findAllByFirstName(firstName));
}
}
It's a very common problem and it occurs because newcomers don't understand how the IoC container works.
Firstly, BeanDefinitionReader reads metadata about your beans from XML, Annotations(#Component, #Service etc), JavaConfig or Groovy script.
There are several BeanPostProcessor's which is responsible for reading all of these Spring annotation you're writing(#Autowired etc).
BeanFactory creates all BeanPostProcessor's then it creates all of your beans.
What happen if you create your bean with #Autowired dependencies via new operator? Nothing, because it isn't actually a bean. The object you created isn't related to IoC container. You may have the bean already in your ApplicationContext if you marked it with #Component(for example) but the object which was created via new operator wont be processed by Spring(annotations won't work).
Hope this helps.
PS: The lifecycle is simplified.
I had the same problem few days ago. What I undertood was that GUI builders like the one that comes with netbeans will automatically create components using new keyword. This means that those components won't be manage by spring. The code usually loks like this:
private void initComponents() {
jPanel1 = new javax.swing.JPanel(); //This component will not be managed by spring.
//...
}
You could use the following class provided here, to make it work.
#Component
public class BeanProvider {
private static ApplicationContext applicationContext;
// Autowires the specified object in the spring context
public static void autowire(Object object) {
applicationContext.getAutowireCapableBeanFactory().autowireBean(object);
}
#Autowired
private void setApplicationContext(ApplicationContext applicationContext) {
BeanProvider.applicationContext = applicationContext;
}
}
The top level SwingApp class:
#SpringBootApplication
public class SwingApp implements CommandLineRunner {
public static void main(String[] args) {
new SpringApplicationBuilder(SwingApp.class)
.headless(false).bannerMode(Banner.Mode.OFF).run(args);
}
#Override
public void run(String... args) throws Exception {
SwingUtilities.invokeLater(() -> {
MainFrame frame = new MainFrame();
frame.setVisible(true);
});
}
}
The MainFrame class:
public class MainFrame extends javax.swing.JFrame {
public MainFrame() {
initComponents();
}
private void initComponents() {
//Gui Builder generated code. Bean not managed by spring.
//Thus, autowired inside CustomPanel won't work if you rely on ComponentScan.
jPanel1 = new CustomJPanel();
//...
}
private CustomJPanel jPanel1;
}
The panel class where you want to autowire things:
//#Component //not needed since it wont work with gui generated code.
public class CustomJPanel extends javax.swing.JPanel{
#Autowired
private SomeRepository someRepository
public CustomJPanel(){
BeanProvider.autowire(this); //use someRepository somewhere after this line.
}
}
I have the same problem in a JavaFx project. Service and Component annotated classes were null in UI controllers even if it was shown in context that it was created. Below code worked for me
#Component
public class FxmlLoaderWithContext {
private final ApplicationContext context;
#Autowired
public FxmlLoaderWithContext(ApplicationContext context) {
this.context = context;
FXMLLoader fxmlloader = new FXMLLoader();
fxmlloader.setControllerFactory(context::getBean); //this row ensure services and components to be autowired
}
}
I think it returns null because you using command new to create object, such as new InputNameForm(). When creating object like that, the object isn't managed by Spring. That's why autowired not working.
The solution is registering your class as a bean.
You can use a class like in here.
#Component
public class BeanProvider {
private static ApplicationContext applicationContext;
public static void autowire(Object object) {
applicationContext.getAutowireCapableBeanFactory().autowireBean(object);
}
#Autowired
private void setApplicationContext(ApplicationContext applicationContext) {
BeanProvider.applicationContext = applicationContext;
}
}
And then, in your class InputNameForm constructor, call this:
class InputNameForm() {
BeanProvider.autowire(this);
...
}
And that's it. Spring will take care the rest.
I'm trying to use dbunit to test my DAOs. We use Spring in a version that is not compatible with spring-test-dbunit. I can't autowire my dao beans into my test class, because then I would have to use #RunWith(SpringJUnit4ClassRunner.class) which regards one parameterless constructor. My class looks like following:
public class DbUnitExample extends DBTestCase {
#Autowired
public MyDAO myDAO;
public DbUnitExample(String name) {
super(name);
System.setProperty(PropertiesBasedJdbcDatabaseTester.DBUNIT_DRIVER_CLASS, "com.mysql.jdbc.Driver");
System.setProperty(PropertiesBasedJdbcDatabaseTester.DBUNIT_CONNECTION_URL, "...");
System.setProperty(PropertiesBasedJdbcDatabaseTester.DBUNIT_USERNAME, "...");
System.setProperty(PropertiesBasedJdbcDatabaseTester.DBUNIT_PASSWORD, "...");
}
#Override
protected IDataSet getDataSet() throws Exception {
return new FlatXmlDataSetBuilder().build(new FileInputStream("target/partial.xml"));
}
#Override
protected DatabaseOperation getSetUpOperation() throws Exception {
return DatabaseOperation.REFRESH;
}
#Override
protected DatabaseOperation getTearDownOperation() throws Exception {
return DatabaseOperation.NONE;
}
#Test
public void testSometing() throws Exception {
myDAO.deleteById(12662);
}
}
Of course I get an NPE because my dao bean can't be found. When I use #RunWith(SpringJUnit4ClassRunner.class) I need to provide one parameterless constructor and have to delete my "dbunit"-constructor. Is there a standard way or workaround to use dbunit with spring without the use of spring-test-dbunit
EDIT
My class now looks like following:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration("/test-application.xml")
#DirtiesContext
#TestExecutionListeners({ DependencyInjectionTestExecutionListener.class, DirtiesContextTestExecutionListener.class })
public class DbUnitExample extends DBTestCase {
#Autowired
public MyDAO myDAO;
public DbUnitExample() {
super("target/partial.xml");
System.setProperty(PropertiesBasedJdbcDatabaseTester.DBUNIT_DRIVER_CLASS, "com.mysql.jdbc.Driver");
System.setProperty(PropertiesBasedJdbcDatabaseTester.DBUNIT_CONNECTION_URL, "...");
System.setProperty(PropertiesBasedJdbcDatabaseTester.DBUNIT_USERNAME, "...");
System.setProperty(PropertiesBasedJdbcDatabaseTester.DBUNIT_PASSWORD, "...");
}
#Override
protected IDataSet getDataSet() throws Exception {
return new FlatXmlDataSetBuilder().build(new FileInputStream("target/partial.xml"));
}
#Override
protected DatabaseOperation getSetUpOperation() throws Exception {
return DatabaseOperation.REFRESH;
}
#Override
protected DatabaseOperation getTearDownOperation() throws Exception {
// return DatabaseOperation.NONE;
// return DatabaseOperation.REFRESH;
return DatabaseOperation.CLEAN_INSERT;
}
#Test
public void testSometing() throws Exception {
myDAO.deleteById(12662);
}
}
It compiles now, but has no dbunt-functionality, which means if I delete a row it doesn't get restored to it's previous state (inserted again).
Since you are using Spring, I suggest autowiring the dbUnit instances into the test. The dbUnit Test Cases page has "Configuration Example Using Spring" for the PrepAndExpectedTestCase, but just copy the code and change it to DBTestCase and adjust accordingly.
1.How to inject a spring bean into thread
2.How to start a thread inside spring bean.
here is my code.
MyThread.java
#Component
public class MyThread implements Runnable {
#Autowired
ApplicationContext applicationContext;
#Autowired
SessionFactory sessionFactory;
public void run() {
while (true) {
System.out.println("Inside run()");
try {
System.out.println("SessionFactory : " + sessionFactory);
} catch (Exception e) {
e.printStackTrace();
}
try {
Thread.sleep(10000);
System.out.println(Arrays.asList(applicationContext.getBeanDefinitionNames()));
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
i am calling run method from below class like (Please suggest if i am following wrong appraoch for calling a thread inside spring bean )
#Component
public class MyServiceCreationListener implements ApplicationListener<ContextRefreshedEvent> {
#Override
public void onApplicationEvent(ContextRefreshedEvent event) {
if (event.getApplicationContext().getParent() == null) {
System.out.println("\nThread Started");
Thread t = new Thread(new MyThread());
t.start();
}
}
}
spring is not performing dependency injection on MyThread class
There are a couple of things wrong with your setup.
You shouldn't be creating and managing threads yourself, Java has nice features for that use those.
You are creating new bean instances yourself and expect Spring to know about them and inject dependencies, that isn't going to work.
Spring provides an abstraction to execute tasks, the TaskExecutor. You should configure one and use that to execute your task not create a thread yourself.
Add this to your #Configuration class.
#Bean
public ThreadPoolTaskExecutor taskExecutor() {
return new ThreadPoolTaskExecutor();
}
Your MyThread should be annotated with #Scope("prototype").
#Component
#Scope("prototype")
public class MyThread implements Runnable { ... }
Now you can inject these beans and an ApplicationContext into your MyServiceCreationListener
#Component
public class MyServiceCreationListener implements ApplicationListener<ContextRefreshedEvent> {
#Autowired
private ApplicationContext ctx;
#Autowired
private TaskExecutor taskExecutor;
#Override
public void onApplicationEvent(ContextRefreshedEvent event) {
if (event.getApplicationContext().getParent() == null) {
System.out.println("\nThread Started");
taskExecutor.execute(ctx.getBean(MyThread.class));
}
}
}
This will give you a pre-configured, fresh instance of MyThread and execute it on a Thread selected by the TaskExecutor at hand.
Your MyThread is created manually rather than via spring context new Thread(new MyThread()); so no chance for spring to inject a bean.
Instead you can add a trick with static access to spring context where you can get a necessary bean from the context (see here or here).
Alternatively you can use ThreadLocal or InheritableThreadLocal to store necessary objects to be used in the thread.
You are creating Thread t = new Thread(new MyThread());.Spring container will not inject the dependency and also not maintain the life cycle of bean.
Example :
#Component
#Scope("prototype")
public class PrintThread extends Thread{
#Override
public void run() {
System.out.println(getName() + " is running");
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(getName() + " is running");
}
}
to access the thread object from spring context.
public class ApplicationContextUtils implements ApplicationContextAware {
private static ApplicationContext ctx;
private static final String USER_THREAD = "printThread";
#Override
public void setApplicationContext(ApplicationContext appContext)
throws BeansException {
ctx = appContext;
}
public static ApplicationContext getApplicationContext() {
return ctx;
}
public static UserService getUserService(){return ctx.getBean(USER_THREAD );}
}
Im building a small application using Spring (Boot, Data, Data Rest).
I have some JpaRepositories that aumotatically are exported as Rest endpoints.
What i want to do is to change the base path from / to /api.
Now to list all people for example i do a GET to http://localhost:8080/people and i want the url to be http://localhost:8080/api/people.
I tried adding this config class but nothing happened (it seems that Spring Boot overrides this config):
public class SpringWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer{
#Override
protected Class<?>[] getRootConfigClasses()
{
return new Class<?>[] { Application.class};
}
#Override
protected Class<?>[] getServletConfigClasses()
{
return new Class<?>[] { RestExporterRestConfig.class, RepositoryRestMvcConfiguration.class };
}
#Override
protected String[] getServletMappings()
{
return new String[] { "/api/*" };
}
}
My Application.java:
#Configuration
#ComponentScan
#Import(RestExporterRestConfig.class)
#EnableJpaRepositories
#EnableAutoConfiguration
public class Application extends SpringBootServletInitializer {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
and RestExporterRestConfig:
#Configuration
public class RestExporterRestConfig extends RepositoryRestMvcConfiguration {
#Bean
public Validator validator() {
return new LocalValidatorFactoryBean();
}
#Override
protected void configureValidatingRepositoryEventListener(ValidatingRepositoryEventListener v) {
v.addValidator("beforeCreate", validator());
}
#Bean
#Qualifier
public DefaultFormattingConversionService defaultConversionService() {
DefaultFormattingConversionService conversionService = new DefaultFormattingConversionService();
conversionService.addConverter(StringToDate.INSTANCE);
return conversionService;
}
#Bean
public DomainClassConverter<?> domainClassConverter() {
return new DomainClassConverter<DefaultFormattingConversionService>(defaultConversionService());
}
}
Well i figured it out. SpringWebAppInitializer is not necesary in this case. I just added this code to Application.java:
#Bean
public ServletRegistrationBean dispatcherRegistration(DispatcherServlet dispatcherServlet) {
ServletRegistrationBean reg = new ServletRegistrationBean(dispatcherServlet);
reg.addUrlMappings("/api/*");
return reg;
}
I think this is the correct way to modify (add, change mappings, etc) servlets using Spring Boot.