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#ConfigurationProperties and #EnableConfigurationProperties cannot bind any properties in .yml or .properties

I want to new a project like mybatis-spring-boot-starter, I use springboot 2.3.2, but something wrong.
First of all, I define a BatisProperties.java like following:
#ConfigurationProperties(prefix = BatisProperties.MYBATIS_PREFIX)
public class BatisProperties {
public static final String MYBATIS_PREFIX = "batis";
private String MyClassName;
...
}
then, a BatisAutoConfiguration.java
#Configuration
#ConditionalOnClass({ SqlSessionFactory.class, SqlSessionFactoryBean.class })
#EnableConfigurationProperties(BatisProperties.class)
public class BatisAutoConfiguration implements InitializingBean {
private final BatisProperties properties;
#Override
public void afterPropertiesSet() throws Exception {
checkConfigFileExists();
}
private void checkConfigFileExists() {
System.out.println(this.properties.getMyClassName());//null here
if (this.properties.isCheckConfigLocation() && //code from mybatis-spring-booot-starter
StringUtils.hasText(this.properties.getConfigLocation())) {
Resource resource = this.resourceLoader.getResource(this.properties.getConfigLocation());
Assert.state(resource.exists(),
"Cannot find config location: " + resource + " (please add config file or check your Mybatis configuration)");
}
}
And in /resource/META_INF/spring.factories
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
xxx.BatisAutoConfiguration
above are all in a starter, I compile it to a jar file and use this jar file in another project(project TWO), in project TWO, I define .properties or .yml in /resource directory, contents are:
batis.my-class-name=xxxx.xxxx
Finally, a DemoApplication.java or Test.java like following:
DemoApplication.java
#SpringBootApplication
public class DemoApplication {
#Autowired
private BatisProperties properties;
private static BatisProperties batisProperties;
#PostConstruct
public void init() {
batisProperties = properties;
}
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
System.out.println(batisProperties.toString());//xxxx.BatisProperties#436390f4
System.out.println(batisProperties.getMyClassName());//null
}
}
Test.java
#SpringBootTest
class Test {
#Autowired
private BatisProperties properties;
#Test
void contextLoads() {
System.out.println(properties);// some bean in Spring IOC
System.out.println(properties.getDatasourceConfigProviderClassName());// null
}
}
Above comments are the results: We can find BatisProperties Bean in Spring IOC, but all properties are null.
So anybody can help? I don't know whether it is caused by the version of SpringBoot

I would improve the BatisProperties class to be as:
#Configuration
#ConfigurationProperties(prefix = "batis")
public class BatisProperties {
private String MyClassName;
...
// Make sure you have getters and setter for properties!
// If you use Lombok, put #Data on this class.
...
}
There is no need to explicitly have BatisAutoConfiguration.java. Just let Spring initialize it for you. Completely remove the class BatisAutoConfiguration.java. Also do not use static fields for the property class.
Try the following:
#SpringBootApplication
#EnableAutoConfiguration
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
Or also more explicit, but not needed:
#SpringBootApplication
#ComponentScan(basePackages = {"my.app.org"}) // prefix, where BatisProperties is
#EnableAutoConfiguration
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
or:
#SpringBootApplication
#EnableAutoConfiguration
#Import(BatisProperties.class)
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
The BatisProperties should be available anywhere in your App.

Spring Boot loading a list from a config file returns empty list

I just created a really basic spring boot application using spring initializer and am trying things out. I want to load a list from a yaml configuration file, but it always returns empty.
I have a custom configuration class
#ConfigurationProperties("example-unit")
#EnableConfigurationProperties
public class ConfigurationUnit {
public List<String> confiList = new ArrayList<>();
public List<String> getConfiList() {
return this.confiList;
}
}
And my main class looks like this
#SpringBootApplication
public class DemoApplication {
static ConfigurationUnit configurationUnit = new ConfigurationUnit();
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
List<String> hello = configurationUnit.getConfiList();
System.out.print("");
}
}
I have put the application.yaml into resources folder.
example-unit:
- string1
- string2
- hello22
I searched here and online, but can't figure out what's the issue and nothing I changed helped. I know I must be doing something wrong.

This statement is wrong static ConfigurationUnit configurationUnit = new ConfigurationUnit();
you should not create the object
Spring only injects the properties into the beans that are handled by application context, and spring creates beans of classes that are annotated with # Configuration
ConfigurationUnit
#Configuration
#ConfigurationProperties("example-unit")
public class ConfigurationUnit {
public List<String> confiList;
public List<String> getConfiList() {
return this.confiList;
}
}
DemoApplication In the spring boot main get the bean from applicationcontext and from it get the list object
#SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
ApplicationContext context = SpringApplication.run(DemoApplication.class, args);
ConfigurationUnit unit = context.getBean("configurationUnit"):
System.out.print(unit. getConfiList());
}
}

Put your list under prefix.property. In your case example-unit.confi-list:. Usually provide a setter for your property: setConfiList(List<String> strings). But since you already initialized it as empty Array list this setter is obsolete says this. There is also advice to add Enable-annotation to Application class:
Application class should have #EnableConfigurationProperties annotation

Here is the reference on how Spring Bboot Configurtion Binding works.
Specifically for your question, this is an example of app that achives your goal:
application.yml
example-unit:
confiList:
- string1
- string2
- hello22
sources
#SpringBootApplication
#EnableConfigurationProperties(ConfigurationUnit.class)
public class DemoApplication {
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(DemoApplication.class, args);
ConfigurationUnit configurationUnit = context.getBean(ConfigurationUnit.class);
System.out.println(configurationUnit.getConfiList());
}
}
#ConfigurationProperties("example-unit")
public class ConfigurationUnit {
public List<String> confiList = new ArrayList<>();
public List<String> getConfiList() {
return this.confiList;
}
}

Here is an example :
Application.yml:
example-unit: string1,string2,hello22
ConfigurationUnit.class:
#Component
#PropertySource(value="classpath:application.yml")
public class ConfigurationUnit {
#Value("#{'${example-unit}'.split(',')}")
private List<String> confiList;
public List<String> getConfiList() {
return confiList;
}
}
DemoFileLoadApplication.class:
#SpringBootApplication
public class DemoFileLoadApplication {
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(DemoFileLoadApplication.class, args);
ConfigurationUnit configurationUnit = context.getBean(ConfigurationUnit.class);
System.out.println(configurationUnit.getConfiList());
}
}
Output:
[string1, string2, hello22]

How use #Autowired with Annotation config?

i create simple spring project and i need to use annotation #Autowired but when i run project, i get exception NullPointerException.
This is my classes:
Main.java
public class Main {
#Autowired
private static InjectClass injectClass;
public static void setInjectClass(InjectClass injectClass) {
Main.injectClass = injectClass;
}
public static void main(String[] args) {
injectClass.hello(); //NullPointerException
}
}
ConfigurationBean
#Configuration
public class ConfigurationBean {
#Bean
public InjectClass injectClass(){
return new InjectClass();
}
}
InjectClass
public class InjectClass {
public void hello(){
System.out.println("Autowired success!");
}
}

You need to initiate application contex before using any bean.
You can do it by writing following code in starting of your main method.
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(
ConfigurationBean.class);

How to externalise neo4j url to application.properites or application.yml in Spring boot

I would like to use application.yml and profiles approach for externalising db and other infrastructure dependencies.
I currently have neo4j url hard coded in the main application.
#Configuration
#EnableNeo4jRepositories("com.xxx.repository")
#Import(RepositoryRestMvcConfiguration.class)
#EnableAutoConfiguration
public class Application extends Neo4jConfiguration {
public Application() {
setBasePackage("com.xxx.entity");
}
#Bean(destroyMethod = "shutdown")
public GraphDatabaseService graphDatabaseService() {
return new SpringRestGraphDatabase("http://127.0.0.1:7474/db/data");
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
UPDATED:
#Value("${neo4jurl}")
private String neoUrl;
#Bean(destroyMethod = "shutdown")
public GraphDatabaseService graphDatabaseService() {
return new SpringRestGraphDatabase(neoUrl);
}
src/main/resources/application.yml
neo4jurl: http://127.0.0.1:7474/db/data

EJB embedded container - dependency injection don't work?

Have a look at following code:
#Local
public interface MyService {
void printMessage();
}
#Stateless
public class MyServiceImpl implements MyService {
#Override
public void printMessage() {
System.out.println("Hello from MyService.");
}
}
#Stateless
#Named
public class Application {
#EJB
public MyService sampleService;
private static Application getApplication() throws NamingException {
Properties properties = new Properties();
properties.setProperty(EJBContainer.APP_NAME, "admin");
EJBContainer.createEJBContainer(properties); //.getContext();
Context context = new InitialContext();
Application application = (Application) context.lookup("java:global/admin/classes/Application");
return application;
}
public static void main(String[] args) throws NamingException {
Application application = getApplication();
application.start(args);
}
private void start(String[] args) {
sampleService.printMessage();
}
}
I expected to have simpletService instance available at start() operation, but it is equal to null. All classes are part of one project (placed in separated files). Where I have made mistake? Thanks for advice.

Finally I have found solution. When I changed start() operation to be public and injection started work fine.