Spring Properties showing as Null - spring

I have a Spring Boot application, generated by JHipster.
Am trying to add some new properties to the application-dev.yml file but my class is seeing the values null, even after spending some hours with Google.
Added the following to the top of application-dev.yml:
host: 1.2.3.4
port: 5555
In my class I have
#Component
public class ExampleUtils {
#Value("${host}")
private String host;
#Value("${port}")
private String port;
}
The class is in a new directory under the source root.
Thanks in advance.

in your application.properties set
spring.profiles.active=dev
or when you run the application parse the command line args follows
-Dspring.profiles.active=dev

It is a good practice to add the new properties you add to a #ConfigurationProperties class.
At least this way I never had problems adding properties.
Have a look at the docs : http://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html#boot-features-external-config-typesafe-configuration-properties

Related

Spring #Value returns <empty>

I have checked similiar questions:
Spring - #Value returns null
Spring Boot: #Value returns always null
Yet, I cannot find what is wrong with my annotation
This how the code looks in IntelliJ
screenshot from IntelliJ
This is whats beneath
#Component
public class VisitMapper {
#Value("${spring.datasource.url}")
private String url;
#Value("${spring.datasource.username}")
private String username;
#Value("${spring.datasource.password}")
private String password;
//more code below
I have two .properties files: application-dev.properties and application.properties.
Active profile is set to dev.
In application-dev.properties I have:
spring.datasource.url=jdbc:postgresql://localhost:5432/postgres
spring.datasource.username=postgres
spring.datasource.password=postgres
Not sure if it is important since active profile is set to dev, but in application.properties I have:
spring.datasource.url=
spring.datasource.username=
spring.datasource.password=
To sum up - why is password value shown as empty?
I suspect that either Intellij hides the fields with password in them (although <empty> is a bit of a crappy filler) or Intellij has a hard time resolving the right property value for that field (for whatever reason).
However the fact that your application starts indicates that, at least, Spring Boot does resolve the properties correctly, else it wouldn't start and blow up. It wouldn't start either due to not being able to resolve the property or due to not being able to connect to the database.

Get Application Name Spring boot

I'm building a module to save the data into the database. After finishing the module I will make it into a JAR which is common and anyone will call static method. There is a parameter its name application name i don’t want pass this value I want get this value dynamic after add jar to any spring boot application , then any one call this static method retrieve name application dynamic , so the spring boot contains the application properties have value spring.application.name I want get this value inside my module it’s doable ? it’s possible to get this value
I searched and found this implementation:
#Value("${spring.application.name}")
private String appName;
My class:
public class BackEnd {
#Value("${spring.application.name}")
static String applicationName;
private static void saveData(String messsage) {
DAO dao= new DAO()
dao.saveData(messsage,applicationName);
}
}
So currently the applicationName value is null. Is it the correct implementation?
The property name is correct and used by a handful of Spring Boot projects. You need to define this property yourself as Spring Boot default is an empty value as per docs:
# IDENTITY (ContextIdApplicationContextInitializer)
spring.application.name= # Application name.
You can use the usual application.yml file e.g.
spring:
application:
name: MyApp
well, the property name is correct but you need to define that property in application.properties or application.yml file as follows.
if you are using application.properties file define property as follows
spring.application.name= # your application name
if you are using application.yml file define property as follows
spring:
application:
name: # your application name

Unable to read values from external property file in Spring Boot

I have a running Spring Boot project. I want to read some environment specific properties from an external properties file.
I mentioned config files names and locations while starting the server as follows:
java -jar AllergiesConditions.jar --spring.config.name=application,metadata --spring.config.location=classpath:/,/APPS/SpringBoot/
The property files loads successfully(because i tried to log one of the external key values inside datasource bean and It printed successfully) But when i try to access a value using #Value annotation - It returns null.
My test Class is as follows:
#Component
public class testclass {
private Logger logger = LogManager.getLogger(testcla.class);
#Value("${sso.server}")
public String sso;
public void test(){
logger.info("sso url is: "+sso); //This sso is logged as null
otherStuff();
}
}
This test() function is called when a particular API is hit after server is running.
The external config file - metadata.properties contains this variable:
sso.server=1234test
Edit: As suggested in this apparently duplicate question I also tried adding #PropertySource(name = "general-properties", value = { "classpath:path to your app.properties"}) in main Application configuration class and It loaded the files, but still I get null value itself.
Can someone please help in what's going wrong here?? Does the testclass need some specific annotation OR it needs to be a bean or something??
Thanks in Advance :)
Thanks to M.Deinum for great input and saving my time
Just posting his comment as answer
Factually ${sso.server} cannot be null. If ${sso.server} couldn't be resolved, my application will break at startup itself.
So the obvious problem was that I was creating a new instance of testclass in my controller using
testclass obj = new testclass(); obj.test();
Rather I should be using spring managed instance by autowiring testclass in my controller.

Reload property value when external property file changes ,spring boot

I am using spring boot, and I have two external properties files, so that I can easily change its value.
But I hope spring app will reload the changed value when it is updated, just like reading from files. Since property file is easy enough to meet my need, I hope I don' nessarily need a db or file.
I use two different ways to load property value, code sample will like:
#RestController
public class Prop1Controller{
#Value("${prop1}")
private String prop1;
#RequestMapping(value="/prop1",method = RequestMethod.GET)
public String getProp() {
return prop1;
}
}
#RestController
public class Prop2Controller{
#Autowired
private Environment env;
#RequestMapping(value="/prop2/{sysId}",method = RequestMethod.GET)
public String prop2(#PathVariable String sysId) {
return env.getProperty("prop2."+sysId);
}
}
I will boot my application with
-Dspring.config.location=conf/my.properties
I'm afraid you will need to restart Spring context.
I think the only way to achieve your need is to enable spring-cloud. There is a refresh endpoint /refresh which refreshes the context and beans.
I'm not quite sure if you need a spring-cloud-config-server (its a microservice and very easy to build) where your config is stored(Git or svn). Or if its also useable just by the application.properties file in the application.
Here you can find the doc to the refresh scope and spring cloud.
You should be able to use Spring Cloud for that
Add this as a dependency
compile group: 'org.springframework.cloud', name: 'spring-cloud-starter', version: '1.1.2.RELEASE'
And then use #RefreshScope annotation
A Spring #Bean that is marked as #RefreshScope will get special treatment when there is a configuration change. This addresses the problem of stateful beans that only get their configuration injected when they are initialized. For instance if a DataSource has open connections when the database URL is changed via the Environment, we probably want the holders of those connections to be able to complete what they are doing. Then the next time someone borrows a connection from the pool he gets one with the new URL.
Also relevant if you have Spring Actuator
For a Spring Boot Actuator application there are some additional management endpoints:
POST to
/env to update the Environment and rebind #ConfigurationProperties and log levels
/refresh for re-loading the boot strap context and refreshing the #RefreshScope beans
Spring Cloud Doc
(1) Spring Cloud's RestartEndPoint
You may use the RestartEndPoint: Programatically restart Spring Boot application / Refresh Spring Context
RestartEndPoint is an Actuator EndPoint, bundled with spring-cloud-context.
However, RestartEndPoint will not monitor for file changes, you'll have to handle that yourself.
(2) devtools
I don't know if this is for a production application or not. You may hack devtools a little to do what you want.
Take a look at this other answer I wrote for another question: Force enable spring-boot DevTools when running Jar
Devtools monitors for file changes:
Applications that use spring-boot-devtools will automatically restart
whenever files on the classpath change.
Technically, devtools is built to only work within an IDE. With the hack, it also works when launched from a jar. However, I may not do that for a real production application, you decide if it fits your needs.
I know this is a old thread, but it will help someone in future.
You can use a scheduler to periodically refresh properties.
//MyApplication.java
#EnableScheduling
//application.properties
management.endpoint.refresh.enabled = true
//ContextRefreshConfig.java
#Autowired
private RefreshEndpoint refreshEndpoint;
#Scheduled(fixedDelay = 60000, initialDelay = 10000)
public Collection<String> refreshContext() {
final Collection<String> properties = refreshEndpoint.refresh();
LOGGER.log(Level.INFO, "Refreshed Properties {0}", properties);
return properties;
}
//add spring-cloud-starter to the pom file.
Attribues annotated with #Value is refreshed if the bean is annotated with #RefreshScope.
Configurations annotated with #ConfigurationProperties is refreshed without #RefreshScope.
Hope this will help.
You can follow the ContextRefresher.refresh() code implements.
public synchronized Set<String> refresh() {
Map<String, Object> before = extract(
this.context.getEnvironment().getPropertySources());
addConfigFilesToEnvironment();
Set<String> keys = changes(before,
extract(this.context.getEnvironment().getPropertySources())).keySet();
this.context.publishEvent(new EnvironmentChangeEvent(context, keys));
this.scope.refreshAll();
return keys;
}

Spring Boot: Change Port for Web Application

I am currently trying to create a web application with Spring Boot. I need to host my application to localhost:8081. How do I change the port?
Actually you want to change server.port and you can change it in many different ways as described http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-external-config
Examples:
in your application.properties (in or outside the jar)
command line
java -Dserver.port=$PORT -jar target/demo-0.0.1-SNAPSHOT.jar
and much more
By default spring boot uses port 8080, BUT you can change the port just by adding the following code line in your main() like this:
System.getProperties().put( "server.port", *YOUR_PORT_NUMBER_GOES_HERE* );
e.g
#SpringBootApplication
public class MyClass {
public static void main(String[] args) {
System.getProperties().put( "server.port", 8181 ); //8181 port is set here
SpringApplication.run(MyClass.class, args);
}
OR
You can configure it in your application.properties file like so:
server.port=8181
If you DON'T have an application.properties file in your spring-boot application, you can go ahead and create one. Right-click on the src/java/resources folder and go to New-> Other-> General and choose 'File' then name as: application.properties
Any other configurations you might need are listed here https://docs.spring.io/spring-boot/docs/current/reference/html/common-application-properties.html. These properties are also configured in the application.properties file.
Actually you want to change server.port and you can change it in many different ways as described
http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-external-config
Put server.port=9000 in your application.properties
In your application.properties file, just add one line
server.port = 8080
And for more configurations you can refer Spring Boot documentation on port
If you are using the embedded tomcat server, you can configure the EmbeddedServletContainerFactory bean yourself in your Application class annotated with #SpringBootApplication.
This will give you options to customize your tomcat server, example configuration
#Bean
public EmbeddedServletContainerFactory servletContainer() {
TomcatEmbeddedServletContainerFactory factory = new TomcatEmbeddedServletContainerFactory();
factory.setPort(9000);
factory.setSessionTimeout(10, TimeUnit.MINUTES);
factory.addErrorPages(new ErrorPage(HttpStatus.NOT_FOUND, "/notfound.html"));
return factory;
}
You could also do the same for Jetty, using the JettyEmbeddedServletContainerFactory bean, or for Undertow using the UndertowEmbeddedServletContainerFactory .
Official documentation found here : http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/
If you're using STS, you can do it following below steps:
Go to Boot Dashboard view, you'll see your Boot app, say myApp1
Right click and click on Open Config. This should open Run Time
Configuration section.
Go to Argument tab and add parameter server.port=, like in the example below, a custom port 9091 is added.
Start the app and if everything is good, you'll see the desired port
on Boot dashboard.
go to your application.properties file and type server.port=8081
see this image

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