It is a very simple program that has a main class as JavaLoader, one interface Student. Student is implemented by two classes.
I have also made a configuration class. When I instantiate the bean from the main class and call a method on Samir. A NoSuchBeanDefinitionException is thrown.
Main class (JavaLoader):
package spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class JavaLoader {
public static void main(String[] args) {
AnnotationConfigApplicationContext appContext = new
AnnotationConfigApplicationContext("StudentConfig.class");
Student samir = (Student) appContext.getBean("samir", Student.class);
System.out.println(samir.readsBook());
}
}
StudentConfig class:
package spring;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
#Configuration
#ComponentScan("spring")
public class StudentConfig {
}
Samir class:
package spring;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Component;
#Component("samir")
public class Samir implements Student{
#Autowired
#Qualifier("history")
Book book;
public Samir(Book book){
this.book = book;
}
public String readsBook(){
return book.readBook();
}
}
The expected output is that the method samir.readsBook() on JavaLoader should be executed
You need to provide a Class instance to the AnnotationConfigApplicationContext constructor:
new AnnotationConfigApplicationContext(StudentConfig.class);
note that StudentConfig.class is not the same as the string "StudentConfig.class".
Note that AnnotationConfigApplicationContext has a string-constructor as well (that's why your code still compiles), but that string is interpreted as a base package for auto-scanning rather than the configuration class name.
Related
If i keep #Pointcut("within(org.example.ShoppingCart.*)") in AuthenticationAspect.java then the authenticate method is NOT getting invoked BUT when i change to #Pointcut("within(org.example..*)") then it does get invoked.
Doesn't the 2nd PointCut below automatically include the first one?
#Pointcut("within(org.example.ShoppingCart.*)")
#Pointcut("within(org.example..*)")
i believe both of these should work.
Following is the code :
ShoppingCart.java
package org.example;
import org.springframework.stereotype.Component;
#Component
public class ShoppingCart {
public void checkout(String status)
{
System.out.println("Checkout method called");
}
}
AuthenticationAspect.java
package org.example;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;
#Aspect
#Component
public class AuthenticationAspect {
#Pointcut("within(org.example.ShoppingCart.*)")
public void authenticationPointCut()
{
}
#Before("authenticationPointCut()")
public void authenticate()
{
System.out.println("Authentication is being performed");
}
}
Main.java
package org.example;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class Main {
public static void main(String[] args) {
ApplicationContext context = new AnnotationConfigApplicationContext(BeanConfig.class);
ShoppingCart cart = context.getBean(ShoppingCart.class);
cart.checkout("CANCELLED");
}
}
BeanConfig.java
package org.example;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;
#Configuration // Indicates this is a configuration class
#ComponentScan(basePackages = "org.example") // Indicates where to find the components/beans
#EnableAspectJAutoProxy // Enables the AspectJ features in project
public class BeanConfig {
}
i am learning spring aspect and unsure why the pointcut expression is not working .
Since the within pointcut designator limits matching to join points of certain types, the problem is your pointcut expression is matching types within ShoppingCart because of .* in the end. If you remove those characters it should work.
#Pointcut("within(org.example.ShoppingCart)")
public void authenticationPointCut(){}
I am trying to connect spring boot application with MySQL for that I have created a interface with name FilterDao which extend JpaRepository class. but whenever I try to make object of implemented class in Service I got this error "Consider defining a bean of type 'com.example.filter.FilterDao' in your configuration" as I am new to spring boot I don't understand this error.
FilterApplication.java
package com.example.filter;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
#SpringBootApplication(exclude = {DataSourceAutoConfiguration.class })
public class FilterApplication {
public static void main(String[] args) {
SpringApplication.run(FilterApplication.class, args);
}
}
FilterDao.java
package com.example.filter;
import com.example.filter.Filter;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.domain.Example;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.query.FluentQuery;
import java.util.List;
import java.util.Optional;
import java.util.function.Function;
//#Configuration
public interface FilterDao extends JpaRepository<Filter, Integer> {
}
FilterService.java
package com.example.filter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
#Service
public class FilterService {
#Autowired
private FilterDao filterDao;
public List<Filter> getData() {
System.out.println("----------------------HERE-------------");
return filterDao.findAll();
}
}
FilterConnector.java
package com.example.filter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
#RestController
public class FilterConnector {
#Autowired
private FilterService filterService;
#GetMapping("/home")
public List<Filter> home()
{
return this.filterService.getData();
}
}
Project Structure
Annotate FilterDao with #Repository
Seems spring has not created bean for FilterDao repository and you are trying to use that`
#Autowired
private FilterDao filterDao;`
There might different reasons for this exception. Please try the below solution.
Use #EnableJpaRepositories(basePackages = "com.example.filter") with your FilterApplication class.
Use #ComponentScan(basePackages = "com.example.*") with FilterApplication class
Use #Repoitory annotation with FilterDao interface.
Hope this helps. For more details check the below tutorial.
https://javatute.com/jpa/consider-defining-a-bean-of-type-in-your-configuration/
Have SpringBoot Java app with different classes. I am not able to inject the dependencies and initialize/access the object of one class into another . Have seen the spring doc and used the annotations (#component,#Autowired etc. ), still there is an issue.
following are the classes.
Main Class ()
package com.test;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.stereotype.Component;
#SpringBootApplication
public class CostmanagementApplication {
public static void main(String[] args) {
SpringApplication.run(CostmanagementApplication.class, args);
}
}
Controller class
package com.test;
import javax.swing.text.rtf.RTFEditorKit;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
#Component
#Controller
public class HighChartsController {
#Autowired
private RequestToken rt;
#GetMapping("/costdata")
public static String customerForm(Model model) {
//here not able to access the getToken() method
model.addAttribute("costdata", new CostDataModel());
return "costdata";
}
}
RequestToken Class
package com.test;
import java.io.IOException;
import java.net.URI;
import java.net.URLEncoder;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpRequest.BodyPublishers;
import java.net.http.HttpResponse;
import java.net.http.HttpResponse.BodyHandlers;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.HashMap;
import java.util.stream.Collectors;
import org.json.JSONObject;
import org.springframework.stereotype.Component;
#Component
public class RequestToken {
public String getToken() throws IOException, InterruptedException {
// TODO Auto-generated method stub
// code to get the token
return token;
}
}
now eventhough , I have all annotation in place , not getting why the getToken() method is not accessible in controller class using rt object. please suggest
Okay, let's go in order.
First of all, all the annotations #Service, #Controller and #Repository are specifications from #Component, so you don't need to specify #Component and #Controller in your HighChartsController.
Actually, if you check what the annotation #Controller definition is, you'll find this:
#Component
public #interface Controller {
...
}
Secondly, I don't really know what do you mean with that you aren't able to access the getToken() method, but as you wrote it seems you tried to access to that method as an static method.
You're injecting the object, so you use the methods of the objects like in plain Java: rt.getToken(). The only difference is that the RequestToken object will be already initialized at the moment you call it.
package com.test;
import javax.swing.text.rtf.RTFEditorKit;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
#Controller
public class HighChartsController {
#Autowired
private RequestToken rt;
#GetMapping("/costdata")
public static String customerForm(Model model) {
String token = rt.getToken();
...
model.addAttribute("costdata", new CostDataModel());
return "costdata";
}
}
I have a Data Loader Class which is suppose to load data once the app starts.
My Error -
Could not autowire. No beans of 'OwnerService' Found.
However, my ownerService class is annotated as I have shown below -
This is the class whose supposed to do that -
DataLoader
import model.Owner;
import model.Vet;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;
import services.OwnerService;
import services.VetService;
import services.map.OwnerServiceMap;
import services.map.VetServiceMap;
#Component
public class DataLoader implements CommandLineRunner {
private final OwnerService ownerService;
private final VetService vetService;
public DataLoader(OwnerService ownerService, VetService vetService) {
this.ownerService = ownerService;
this.vetService = vetService;
}
OwnerServiceMap
package services.map;
import model.Owner;
import org.springframework.stereotype.Service;
import services.OwnerService;
import java.util.Set;
#Service
public class OwnerServiceMap extends AbstractMapService<Owner,Long> implements OwnerService
{//some code here}
The vetService is the same as ownerService.
My applcation class -
package petclinic;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class PetclinicApplication {
public static void main(String[] args) {
SpringApplication.run(PetclinicApplication.class, args);
}
}
Maybe I have hierarchy problems, as the application class doesn't search for beans in enough places in the project?
Thank you!
Can you please provide me with an example of primitive type dependency injection in spring boot. I have tried once but TestConfiguration which is my custom bean definition class does not detect or does not recognize by spring boot application.
here is my code,
//Engine class
package com.test2.projectTest;
import org.springframework.stereotype.Component;
#Component
public class Engine {
private String msg;
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
}
//Test Configuration
package com.test2.projectTest;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
#Configuration
public class TestConfiguration {
#Bean("engine")
public Engine engine(){
Engine engine = new Engine();
engine.setMsg("Message is injected");
return engine;
}
}
//spring main application
package com.test2.projectTest;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
#SpringBootApplication
public class ProjectTestApplication {
public static void main(String[] args) {
SpringApplication.run(ProjectTestApplication.class, args);
}
}
//JUnit Test
package com.test2.projectTest;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.TestConfiguration;
import org.springframework.context.ApplicationContext;
import
org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.test.context.junit4.SpringRunner;
#RunWith(SpringRunner.class)
#SpringBootTest
public class ProjectTestApplicationTests {
#Test
public void contextLoads() {
ApplicationContext apc = new
AnnotationConfigApplicationContext(TestConfiguration.class);
Engine e = (Engine) apc.getBean("engine");
e.getMsg();
}
}
// Output - org.springframework.beans.factory.NoSuchBeanDefinitionException:
No bean named 'engine' available
Please suggest any solution to above issue
Add #componentscan annotation in main class and provide engine class package and it should work