I want to add a property in application.properties of my spring boot application and be able to to access it and use it in one of my other classes, but I am getting null.
Here is my application.properties
server.port=8052
subscribe.period=5
My class that will access it
#Component
public class SubscriptionService {
#Value("${subscribe.period}")
private String period
#Autowired
public SubscriptionService(String period) {
String time = period;
...
}
}
But it seems period is not being populated, in fact null. It shows as nill when I run as maven build in eclipse at least, im thinking it might be trying to access it before the properties file is even load, if so how might i approach this?
Deinum in the comments above is correct. I have no idea why as it differs from every other online example I have read so I would invite him to give an explanation.
I had to put the #Value in the argument of the constructor
#Component
public class SubscriptionService {
private String period
#Autowired
public SubscriptionService(#Value("${subscribe.period}") String period) {
String time = period;
...
}
}
Then it works
Related
I have a spring-boot application where I read data from queue and send data to transformation class using .bean()
Integration.java
class Integration {
#Value("${someURL}")
private String someURL; //able to read someURL from property file
from("queue")
// some intermediate code
.bean(new TransformationClass(), "transformationMethod")
// other code
}
Now, Inside TransformationClass I have #Value annotation to read values from properties file but it always returns a null.
TransformationClass.java
#Component
class TransformationClass {
#Value("${someURL}")
private String someURL; //someURL return null though there is key-value associated in props file.
public void transformationMethod(Exchange exchange) {
// other stuff related to someURL
}
}
Note - I am able to read values from property file in class Integration.java but unable to read from class TransformationClass.java
I am using spring boot version - 2.7.2 and camel version - 3.18.1 jdk - 17
I tried to read using camel PropertiesComponent but it did not worked.
Problem here is, that new TransformationClass() is not a "spring managed instance", thus all #Autowire/Value/Inject/...s have no effect.
Since TransformationClass is (singleton, spring-managed) #Component and is needed by Integration, wiring these makes sense:
Via field... :
class Integration {
#Autowired
private TransformationClass trnsObject;
// ...
Or constructor injection:
class Integration {
private final TransformationClass trnsObject;
public Integration(/*im- /explicitely #Autowired*/ TransformationClass pTrnsObject) {
trnsObject = pTrnsObject;
}
// ...
// then:
doSomethingWith(trnsObject); // has correct #Values
}
I have written queries in property file. I want to read the property file in to one class with annotations in spring boot. How can i read it? And is there any better approach for writing queries in spring boot project?
If you add your properties in application.properties file, you can read them inside the spring boot classes like:
#Service
public class TwitterService {
private final String consumerKey;
private final String consumerKeySecret;
#Autowired
public TwitterService(#Value("${spring.social.twitter.appId}") String consumerKey, #Value("${spring.social.twitter.appSecret}") String consumerKeySecret) {
this.consumerKey = consumerKey;
this.consumerKeySecret = consumerKeySecret;
} ...
You can annotate fields in your components by #Value("${property.name}")
Else, you can use Properties Object in java.util package.
For example, i have a mode property, which values are dev or prod, i can use it in my beans as follow :
#Value("${mode:dev}")
private String mode;
The other approach is by using :
Properties pro = new Properties();
pro.load(this.getClass().getClassLoader().getResourceAsStream());
You can use #PropertySource to read the properties from a file and then pass them to a bean. If you have a file called "queries.properties" that has a property like:
query1: select 1 from foo
Then your config might look like:
#PropertySource("classpath:queries.properties")
#Configuration
public class MyConfig {
#Bean
public DbBean dbBean(#Value("${queries.query1}") String query) {
return new DbBean(query);
}
}
I've defined an application name using the bootstrap.yml file in my spring boot application.
spring:
application:
name: abc
How can i get this application name during runtime/programmatically ?
You should be able to use the #Value annotation to access any property you set in a properties/YAML file:
#Value("${spring.application.name}")
private String appName;
#Autowired
private ApplicationContext applicationContext;
...
this.applicationContext.getId();
Please, find this:
# IDENTITY (ContextIdApplicationContextInitializer)
spring.application.name=
spring.application.index=
In Spring Boot Reference Manual.
And follow with source code for that ContextIdApplicationContextInitializer class:
#Override
public void initialize(ConfigurableApplicationContext applicationContext) {
applicationContext.setId(getApplicationId(applicationContext.getEnvironment()));
}
Where the default behavior is with this:
/**
* Placeholder pattern to resolve for application name
*/
private static final String NAME_PATTERN = "${vcap.application.name:${spring.application.name:${spring.config.name:application}}}";
Since the #Value annotation is discouraged in Spring Boot when referencing configuration properties, and because applicationContext.getId(); doesn't always return the value of spring.application.name another way is to get the value from the Environment directly
private final Environment environment;
...
public MyBean(final Environment environment) {
this.environment = environment;
}
...
private getApplicationName() {
return this.environment.get("spring.application.name");
}
Another possible way would be to create your own ConfigurationProperties class to get access to the value.
I'm not saying these are the best ways, and I hope/wish that there is a better way, but it is a way.
Note! If your using a SpringBootTest, you need to suplly the properties/yml.
Otherwise, the environment/appcontext does not load the config files.
The, your app name is not set.
Like so:
#PropertySource("classpath:application.properties")
#RunWith(SpringRunner.class)
#SpringBootTest
....
This post is aged but I hate unanswered questions.
So use the following snippet:
#Value("${spring.application.name [: defaultValue]}")
private String appName;
What is between [] is optional.
So I found a really ugly way to do this, but it works so I'm not searching further. Maybe this will help someone.
The basic premise is that spring Environment stores the value inside a propertySource.. It appears that bootstrap config is stored in the ResourcePropertySource and so you can get it from that. For me it is currently throwing an exception, but then I can get the value out of the exception, so I haven't looked any further:
try {
this.environment.getProperty("name", ResourcePropertySource.class);
} catch (ConversionFailedException e) {
String res = (String)e.getValue();
}
And then you can just do this for every property you are interested in.
Like I said ugly, but it works.
I would like to port two projects to Spring Boot 1.1.6. The are each part of a larger project. They both need to make SQL connections to 1 of 7 production databases per web request based region. One of them persists configuration setting to a Mongo database. They are both functional at the moment but the SQL configuration is XML based and the Mongo is application.properties based. I'd like to move to either xml or annotation before release to simplify maintenance.
This is my first try at this forum, I may need some guidance in that arena as well. I put the multi-database tag on there. Most of those deal with two connections open at a time. Only one here and only the URL changes. Schema and the rest are the same.
In XML Fashion ...
#Controller
public class CommonController {
private CommonService CommonService_i;
#RequestMapping(value = "/rest/Practice/{enterprise_id}", method = RequestMethod.GET)
public #ResponseBody List<Map<String, Object>> getPracticeList(#PathVariable("enterprise_id") String enterprise_id){
CommonService_i = new CommonService(enterprise_id);
return CommonService_i.getPracticeList();
}
#Service
public class CommonService {
private ApplicationContext ctx = null;
private JdbcTemplate template = null;
private DataSource datasource = null;
private SimpleJdbcCall jdbcCall = null;
public CommonService(String enterprise_id) {
ctx = new ClassPathXmlApplicationContext("database-beans.xml");
datasource = ctx.getBean(enterprise_id, DataSource.class);
template = new JdbcTemplate(datasource);
}
Each time a request is made, a new instance of the required service is created with the appropriate database connection.
In the spring boot world, I've come across one article that extended TomcatDataSourceConfiguration.
http://xantorohara.blogspot.com/2013/11/spring-boot-jdbc-with-multiple.html That at least allowed me to create a java configuration class however, I cannot come up with a way to change the prefix for the ConfigurationProperties per request like I am doing with the XML above. I can set up multiple configuration classes but the #Qualifier("00002") in the DAO has to be a static value. //The value for annotation attribute Qualifier.value must be a constant expression
#Configuration
#ConfigurationProperties(prefix = "Region1")
public class DbConfigR1 extends TomcatDataSourceConfiguration {
#Bean(name = "dsRegion1")
public DataSource dataSource() {
return super.dataSource();
}
#Bean(name = "00001")
public JdbcTemplate jdbcTemplate(DataSource dsRegion1) {
return new JdbcTemplate(dsRegion1);
}
}
On the Mongo side, I am able to define variables in the configurationProperties class and, if there is a matching entry in the appropriate application.properties file, it overwrites it with the value in the file. If not, it uses the value in the code. That does not work for the JDBC side. If you define a variable in your config classes, that value is what is used. (yeah.. I know it says mondoUrl)
#ConfigurationProperties(prefix = "spring.mongo")
public class MongoConnectionProperties {
private String mondoURL = "localhost";
public String getMondoURL() {
return mondoURL;
}
public void setMondoURL(String mondoURL) {
this.mondoURL = mondoURL;
}
There was a question anwsered today that got me a little closer. Spring Boot application.properties value not populating The answer showed me how to at least get #Value to function. With that, I can set up a dbConfigProperties class that grabs the #Value. The only issue is that the value grabbed by #Value is only available in when the program first starts. I'm not certain how to use that other than seeing it in the console log when the program starts. What I do know now is that, at some point, in the #Autowired of the dbConfigProperties class, it does return the appropriate value. By the time I want to use it though, it is returning ${spring.datasource.url} instead of the value.
Ok... someone please tell me that #Value is not my only choice. I put the following code in my controller. I'm able to reliably retrieve one value, Yay. I suppose I could hard code each possible property name from my properties file in an argument for this function and populate a class. I'm clearly doing something wrong.
private String url;
//private String propname = "${spring.datasource.url}"; //can't use this
#Value("${spring.datasource.url}")
public void setUrl( String val) {
this.url = val;
System.out.println("==== value ==== " + url);
}
This was awesome... finally some progress. I believe I am giving up on changing ConfigurationProperties and using #Value for that matter. With this guy's answer, I can access the beans created at startup. Y'all were probably wondering why I didn't in the first place... still learning. I'm bumping him up. That saved my bacon. https://stackoverflow.com/a/24595685/4028704
The plan now is to create a JdbcTemplate producing bean for each of the regions like this:
#Configuration
#ConfigurationProperties(prefix = "Region1")
public class DbConfigR1 extends TomcatDataSourceConfiguration {
#Bean(name = "dsRegion1")
public DataSource dataSource() {
return super.dataSource();
}
#Bean(name = "00001")
public JdbcTemplate jdbcTemplate(DataSource dsRegion1) {
return new JdbcTemplate(dsRegion1);
}
}
When I call my service, I'll use something like this:
public AccessBeans(ServletRequest request, String enterprise_id) {
ctx = RequestContextUtils.getWebApplicationContext(request);
template = ctx.getBean(enterprise_id, JdbcTemplate.class);
}
Still open to better ways or insight into foreseeable issues, etc but this way seems to be about equivalent to my current XML based ways. Thoughts?
I have requirement for spring mvc 3 caching. Requirement is : while starting the server, we need to call database for one dropdown and put those values in the cache. So that whenever we required those values, we need to retrieve from cache.
Please help me with an example.
Thanks in advance.
May be you can use init-method (Spring 2.5) or #PostConstruct annotation (in Spring 3.0).
This method will be called during server start up
The following is code snippet
#Component
public class CacheDBData {
private String values[];
//add setter & getter
//This will be called during server start up after properties are initialised
#PostConstruct
public void getDataFromDB() {
values = //Logic to get data from DB and store that in values property
}
}
Suppose for example you can use in class as follows
#controller
public class HomeController {
#Autowired
private CacheDBData cacheDBData ;
//getter and setters
private void methodxyz() {
String values[] = cacheDBData.getValues();
}
}
I've had success with Ehcahe for Spring. There's a couple of config files to setup but after that you simply annotate the methods you want to cache the output from and it just works.
This has the advantage that you can change the values coming back from the service/database and NOT have to restart your app, unlike the accepted answer.