I have this part of code:
#Component
public class TestWriter implements ItemWriter<Test> {
// #Value("${test.param:3}")
// private int testParam;
private final ForkJoinPool customThreadPool = new ForkJoinPool(3);
But in new ForkJoinPool(int parallelism) i want to pass as parameter my parameter from application.properties (testParam)
private final ForkJoinPool customThreadPool = new ForkJoinPool(testParam);
I tried to use Enviroment with my params but it doesnt work.
#Autowired
private Environment env;
...
dataSource.setUrl(env.getProperty("jdbc.url"));
How can it be done if it possible and correct and what would be the correct way ?
Thank you
Use Contructor injection to be sure, the property is available when needed.
#Component
public class TestWriter implements ItemWriter<Test> {
private final ForkJoinPool customThreadPool;
#Autowired
public TestWriter (#Value("${test.param:3}") int testParam) {
this.customThreadPool = new ForkJoinPool(testParam);
}
There are two ways in achieving this. One is through environmental variable, and other one is through property file.
Through Environment variable-
You'll need to set environment variable as JDBC_URL=jdbc:postg....
and use it as below.
#Autowired
private Environment env;
...
dataSource.setUrl(env.getProperty("JDBC_URL"));
Through property file,
#Value("${jdbc.url}")
private String JDBC_URL;
In your application.properties, add
jdbc.url=jdbc:postg...
I have a singleton class that I created that is used as an adapter to our Influx database. It basically looks like:
public class InfluxDBAdapter {
// some private static final query Strings
private static InfluxDBAdapter adapter = null;
private static InfluxDB influxDB;
private InfluxDBAdapter() {}
public static InfluxDBAdapter getInstance() {
if (adapter == null) {
adapter = new InfluxDBAdapter();
influxDB = InfluxDBFactory.connect(URL, USERNAME, PWD);
influxDB.query(new Query(CREATE_DB, DB_NAME));
influxDB.setLogLevel(InfluxDB.LogLevel.BASIC);
influxDB.setDatabase(DB_NAME);
}
return adapter;
}
// some more methods to utilize the database
}
and then in another class, I use it like so:
#Service
public class SomeService {
private InfluxDBAdapter adapter;
public SomeService() {}
#PostConstruct
public void init() {
adapter = InfluxDBAdapter.getInstance();
}
}
And so this works, but I'm in the midst of refactoring my code and I wanted to know if was possible to simply autowire my InfluxDBAdapter class vs what I'm currently doing and still achieve the same result?
Create an #Configuration class which both constructs the InfluxDB as well as your adapter. With this you could even make use of the Spring Boot properties support.
#Configuration
public class InfluxDBConfiguration {
#Bean
public InfluxDB influxDB() {
InfluxDB influxDB = InfluxDBFactory.connect(URL, USERNAME, PWD);
influxDB.query(new Query(CREATE_DB, DB_NAME));
influxDB.setLogLevel(InfluxDB.LogLevel.BASIC);
influxDB.setDatabase(DB_NAME);
return influxDB;
}
#Bean
public InfluxDBAdapter influxDBAdapter(InfluxDB influxDB) {
return new InfluxDBAdapter(influxDB);
}
}
Now your InfluxDBAdapter needs a constructor (for dependency injection) retrieving the InfluxDB.
public class InfluxDBAdapter {
// some private static final query Strings
private InfluxDB influxDB;
InfluxDBAdapter(InfluxDB influxDB) {
this.influxDB=influxDB;
}
// some more methods to utilize the database
}
Make sure that the InfluXDBConfiguration and InfluxDBAdapter are in the same package so that the default visible constructor can be called (default visible to prevent, easy, outside instantiation).
In the InflxuDBConfiguration you could remove the static fields containing the hardcoded username etc. and replace it with access to either the Environment or use an #ConfigurationProperties annotated class to work with type safe properties.
#ConfigurationProperties(prefix="influxdb")
#Component
public class InfluxDBProperties {
private String url = "default-url";
private String dbName = "default-dbname";
private String username = "default-user";
private String password = "default-pwd";
// Other properties of your liking;
// getters & setters
}
Now with this InfluxDBProperties you could add influx.url=http://whatever to your application.properties or profile specific one and have it externally configurable. You can inject it into the influxDB method to retrieve the properties from.
#Bean
public InfluxDB influxDB(InfluxDBProperties props) {
InfluxDB influxDB = InfluxDBFactory.connect(props.getUrl(), props.getUsername(), props.getPassword());
influxDB.query(new Query(CREATE_DB, props.getDbName()));
influxDB.setLogLevel(InfluxDB.LogLevel.BASIC);
influxDB.setDatabase(props.getDbName());
return influxDB;
}
No more statics, configurable for every environment.
Yes, this should work. Spring can invoke private constructors so there shouldn't be any issue.
But why would you want to do this? The singleton pattern goes against the basic tenant of dependency injection. If you want a singleton InfluxDBAdapter bean, just make it a singleton bean.
I would recommend adding a configuration class, which could look something like
#Configuration
public class InfluxDBConfig {
// constants omitted...
#Bean
public InfluxDB influxDB() {
final InfluxDB influxDB = InfluxDB(URL, USERNAME, PWD);
influxDB.query(new Query(CREATE_DB, DB_NAME));
influxDB.setLogLevel(InfluxDB.LogLevel.BASIC);
influxDB.setDatabase(DB_NAME);
return influxDB;
}
}
You can then annotate InfluxDBAdapter with #Component since the InfluxDB instance can be injected. Modify the constructors of the InfluxDB and InfluxDBAdapter classes accordingly, of course.
Some of these constants can probably be provided through configuration properties so that your configuration logic isn't mangled with your business logic.
I'm aware of that this topic might be considered as offtopic or convention/opinion based, but I have not found any other place that I could find solution for my problem.
I'm writing and Spring application, fully configured with annotations in Java. I'm loading the properties file with #PropertySource annotation:
#Configuration
#ComponentScan("myapp.app")
#PropertySource("app.properties")
public class ApplicationConfig {
#Bean
public static PropertySourcesPlaceholderConfigurer getPropertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
}
Let's assume, that I have app.properties file of following content:
property1=someProperty1Value
property2=someProperty2Value
I'm loading this value with following code:
#Service
public class MyServiceImpl implements MyService {
#Value("${property1}")
private String property1Value;
#Value("${property2}")
private String property2Value;
#Override
public void doStuff() {
System.out.println(property1Value);
System.out.println(property2Value);
}
}
This is working perfectly fine. On the other hand, I find it hard to maintain - if some will think that "property1" is not the best name for a property and would like to rename it, then it will be needed to find all strings "${property1}" and rename it. I tought that I could extract it to the constant class:
public final class Properties {
public static final String PROPERTY_1 = "${property1}";
public static final String PROPERTY_2 = "${property2}";
private Properties() {
}
}
This requires refactoring of the existing bindings to new constant values:
#Value(Properties.PROPERTY_1)
private String property1Value;
Looks nice, but I do not like the mess in the Properties class, I think it will be better to the constant values without bracelets:
public static final String PROPERTY_1 = "property1";
Which leads to another refactoring in the MyServiceImpl class:
#Value("${" + Properties.PROPERTY_1 + "}")
private String property1Value;
But boy, that's really ugly. I thought about extracting constant values to the Enum:
public enum Properties {
PROPERTY_1("property1"),
PROPERTY_2("property2");
private final String key;
private Properties(String key) {
this.key = key;
}
public String getKey() {
return key;
}
public String getSpringKey() {
return "${" + getKey() + "}";
}
}
and use it like
#Value(Properties.PROPERTY_1.getSpringKey())
private String property1Value;
but then IDE reminded me, that annotation value has to be a constant.
After creating this enum, I thought that I might be over-thinking it, and it should be kept as simple as possible. Currently I came back to the solution with constants in format of
public static final String PROPERTY_1 = "${property1}";
Finally, I would like to ask you to provide another, nice-looking solution, or some reference links where I could read about some common solution.
I am using below config.yml
# AWS DynamoDB settings
dynamoDB:
# Access key
aws_access_key_id: "access-key"
#Secret Key
aws_secret_access_key: "secret-key"
aws_dynamodb_region: EU_WEST_1
And below class to read the above config values in my DynamoDBConfig class.
public class DynamoDBConfig {
public DynamoDBConfig() {
}
#JsonProperty("aws_access_key_id")
public String accessKey;
#JsonProperty("aws_secret_access_key")
public String secretKey;
#JsonProperty("aws_dynamodb_region")
public String region;
// getters and setters
}
Finally ApplicationConfig class which include DynamoDB config.
public class ReadApiConfiguration extends Configuration {
#NotNull
private DynamoDBConfig dynamoDBConfig = new DynamoDBConfig();
#JsonProperty("dynamoDB")
public DynamoDBConfig getDynamoDBConfig() {
return dynamoDBConfig;
}
#JsonProperty("dynamoDB")
public void setDynamoDBConfig(DynamoDBConfig dynamoDBConfig) {
this.dynamoDBConfig = dynamoDBConfig;
}
}
Now i want to read aws_access_key and aws_secret_key values in my AWSclient.java class to create a awsclient
BasicAWSCredentials awsCreds = new BasicAWSCredentials("access_key_id", "secret_key_id");
My problem is, how i read/inject the config values, in my AWSClient class. I am using the dropwizard-guice module for DI. and couldn't figure out , how can i bind the configuration object created at the DW startup time to its class.
P.S. :-> I've gone through this SO post but it doesn't solve my issue, as its not using guice as a DI module.
Normally, you can inject your configuration object either into a class field or into a constructor, like:
public class AWSclient {
#Inject
public AWSclient(ReadApiConfiguration conf) {
initConnection(conf.getDynamoDBConfig().getSecretKey(), ...)
}
}
Additionally, annotate your ReadApiConfiguration class with the #Singleton annotation.
I want to access values provided in application.properties, e.g.:
logging.level.org.springframework.web: DEBUG
logging.level.org.hibernate: ERROR
logging.file=${HOME}/application.log
userBucket.path=${HOME}/bucket
I want to access userBucket.path in my main program in a Spring Boot application.
You can use the #Value annotation and access the property in whichever Spring bean you're using
#Value("${userBucket.path}")
private String userBucketPath;
The Externalized Configuration section of the Spring Boot docs, explains all the details that you might need.
Another way is injecting org.springframework.core.env.Environment to your bean.
#Autowired
private Environment env;
....
public void method() {
.....
String path = env.getProperty("userBucket.path");
.....
}
#ConfigurationProperties can be used to map values from .properties( .yml also supported) to a POJO.
Consider the following Example file.
.properties
cust.data.employee.name=Sachin
cust.data.employee.dept=Cricket
Employee.java
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;
#ConfigurationProperties(prefix = "cust.data.employee")
#Configuration("employeeProperties")
public class Employee {
private String name;
private String dept;
//Getters and Setters go here
}
Now the properties value can be accessed by autowiring employeeProperties as follows.
#Autowired
private Employee employeeProperties;
public void method() {
String employeeName = employeeProperties.getName();
String employeeDept = employeeProperties.getDept();
}
Currently, I know about the following three ways:
1. The #Value annotation
#Value("${<property.name>}")
private static final <datatype> PROPERTY_NAME;
In my experience there are some situations when you are not
able to get the value or it is set to null.
For instance, when you try to set it in a preConstruct() method or an init() method. This happens because the value injection happens after the class is fully constructed. This is why it is better to use the third option.
2. The #PropertySource annotation
#PropertySource("classpath:application.properties")
// 'env' is an Environment variable
env.getProperty(configKey);
PropertySouce sets values from the property source file in an Environment variable (in your class) when the class is loaded.
So you able to fetch easily afterword.
Accessible through System Environment variable.
3. The #ConfigurationProperties annotation.
This is mostly used in Spring projects to load configuration properties.
It initializes an entity based on property data.
#ConfigurationProperties identifies the property file to load.
#Configuration creates a bean based on configuration file variables.
#ConfigurationProperties(prefix = "user")
#Configuration("UserData")
class user {
// Property & their getter / setter
}
#Autowired
private UserData userData;
userData.getPropertyName();
You can do it this way as well....
#Component
#PropertySource("classpath:application.properties")
public class ConfigProperties {
#Autowired
private Environment env;
public String getConfigValue(String configKey){
return env.getProperty(configKey);
}
}
Then wherever you want to read from application.properties, just pass the key to getConfigValue method.
#Autowired
ConfigProperties configProp;
// Read server.port from app.prop
String portNumber = configProp.getConfigValue("server.port");
Follow these steps.
Create your configuration class like below. You can see:
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.beans.factory.annotation.Value;
#Configuration
public class YourConfiguration {
// Passing the key which you set in application.properties
#Value("${userBucket.path}")
private String userBucket;
// Getting the value from that key which
// you set in application.properties
#Bean
public String getUserBucketPath() {
return userBucket;
}
}
When you have a configuration class then inject in the variable from a configuration where you need.
#Component
public class YourService {
#Autowired
private String getUserBucketPath;
// Now you have a value in the getUserBucketPath
// variable automatically.
}
You can use the #Value to load variables from the application.properties if you will use this value in one place, but if you need a more centralized way to load these variables #ConfigurationProperties is a better approach.
Additionally, you can load variables and cast them automatically if you need different data types to perform your validations and business logic.
application.properties
custom-app.enable-mocks = false
#Value("${custom-app.enable-mocks}")
private boolean enableMocks;
You can use #Value("${property-name}") from the
application.properties if your class is annotated with
#Configuration or #Component.
There's one more way I tried out was making a Utility class to read properties in the following way -
protected PropertiesUtility () throws IOException {
properties = new Properties();
InputStream inputStream =
getClass().getClassLoader().getResourceAsStream("application.properties");
properties.load(inputStream);
}
You can make use of static method to get the value of the key passed as the parameter.
You should inject #Autowired private Environment env; from import org.springframework.core.env.Environment;
And then use it this way:
env.getProperty("yourPropertyNameInApplication.properties")
#Value Spring annotation is used for injecting values into fields in Spring-manged beans, and it can be applied to the field or constructor/method parameter level.
Examples
String value from the annotation to the field
#Value("string value identifire in property file")
private String stringValue;
We can also use the #Value annotation to inject a Map property.
First, we'll need to define the property in the {key: ‘value' } form in our properties file:
valuesMap={key1: '1', key2: '2', key3: '3'}
Not that the values in the Map must be in single quotes.
Now inject this value from the property file as a Map:
#Value("#{${valuesMap}}")
private Map<String, Integer> valuesMap;
To get the value of a specific key
#Value("#{${valuesMap}.key1}")
private Integer valuesMapKey1;
We can also use the #Value annotation to inject a List property.
#Value("#{'${listOfValues}'.split(',')}")
private List<String> valuesList;
To pick the values from property file, we can have a Config reader class, something like ApplicationConfigReader.java.
Then define all the variables against properties. Refer to the below example,
application.properties
myapp.nationality: INDIAN
myapp.gender: Male
Below is the corresponding reader class.
#Component
#EnableConfigurationProperties
#ConfigurationProperties(prefix = "myapp")
class AppConfigReader{
private String nationality;
private String gender
// Getter and setter
}
Now we can auto-wire the reader class wherever we want to access property values.
E.g.,
#Service
class ServiceImpl{
#Autowired
private AppConfigReader appConfigReader;
//...
// Fetching values from the configuration reader
String nationality = appConfigReader.getNationality() ;
String gender = appConfigReader.getGender();
}
An application can read three types of values from the application.properties file.
application.properties
my.name = kelly
my.dbConnection = {connection_srting:'http://localhost:...', username:'benz', password:'pwd'}
Class file
#Value("${my.name}")
private String name;
#Value("#{${my.dbConnection}}")
private Map<String,String> dbValues;
If you don't have a property in application.properties then you can use the default value:
#Value("${your_name: default value}")
private String msg;
You can use the #Value annotation for reading values from an application.properties/yml file.
#Value("${application.name}")
private String applicationName;
There are 3 ways to read the application.properties,
using #Value, EnvironmentInterface and #ConfigurationProperties..
#Value(${userBucket.path})
private String value;
2nd way:
#Autowired
private Environment environment;
String s = environment.getProperty("userBucket.path");
3rd way:
#ConfigurationProperties("userbucket")
public class config {
private String path;
//getters setters
}
Can be read with getters and setters..
Reference - here
Injecting a property with the #Value annotation is straightforward:
#Value("${jdbc.url}")
private String jdbcUrl;
We can obtain the value of a property using the Environment API
#Autowired
private Environment env;
...
dataSource.setUrl(env.getProperty("jdbc.url"));
Another way to find a key/value in the configuration.
...
import org.springframework.core.env.ConfigurableEnvironment;
...
#SpringBootApplication
public class MyApplication {
#Autowired
private ConfigurableEnvironment myEnv;
...
#EventListener(ApplicationReadyEvent.class)
public void doSomethingAfterStartup()
throws Exception {
LOG.info("myEnv (userBucket.path): " + myEnv.getProperty("userBucket.path"));
}
}
You can access the application.properties file values by using:
#Value("${key_of_declared_value}")
The best ways to get property values are using:
1. Using Value annotation
#Value("${property.key}")
private String propertyKeyVariable;
2. Using the Environment bean
#Autowired
private Environment env;
public String getValue() {
return env.getProperty("property.key");
}
public void display() {
System.out.println("# Value : " + getValue);
}
Spring Boot allows us several methods to provide externalized configurations. You can try using file application.yml or YAML files instead of the property file and provide different property files setup according to different environments.
We can separate out the properties for each environment into separate YAML files under separate Spring profiles. Then during deployment you can use:
java -jar -Drun.profiles=SpringProfileName
to specify which Spring profile to use. Note that the YAML files should be named like
application-{environmentName}.yml
for them to be automatically taken up by Spring Boot.
Reference: 2. Externalized Configuration
To read from the application.yml or property file:
The easiest way to read a value from the property file or YAML is to use the Spring #value annotation. Spring automatically loads all values from the YAML file to the Spring environment, so we can directly use those values from the environment like:
#Component
public class MySampleBean {
#Value("${name}")
private String sampleName;
// ...
}
Or another method that Spring provides to read strongly-typed beans is as follows:
YML
ymca:
remote-address: 192.168.1.1
security:
username: admin
Corresponding POJO to read the YAML content:
#ConfigurationProperties("ymca")
public class YmcaProperties {
private InetAddress remoteAddress;
private final Security security = new Security();
public boolean isEnabled() { ... }
public void setEnabled(boolean enabled) { ... }
public InetAddress getRemoteAddress() { ... }
public void setRemoteAddress(InetAddress remoteAddress) { ... }
public Security getSecurity() { ... }
public static class Security {
private String username;
private String password;
public String getUsername() { ... }
public void setUsername(String username) { ... }
public String getPassword() { ... }
public void setPassword(String password) { ... }
}
}
The above method works well with YAML files.
Reference: 2. Externalized Configuration
There are two ways to access the value from the application.properties file:
Using the #Value annotation
#Value("${property-name}")
private data_type var_name;
Using an instance of the Environment class
#Autowired
private Environment environment;
// Access this way in the method where it's required
data_type var_name = environment.getProperty("property-name");
You can also inject an instance of the environment using constructor injection or creating a bean yourself.
Try class PropertiesLoaderUtils. This approach doesn’t use any annotation of Spring Boot. It is a traditional class way.
Example:
Resource resource = new ClassPathResource("/application.properties");
Properties props = PropertiesLoaderUtils.loadProperties(resource);
String url_server=props.getProperty("server_url");
Use the getProperty() method to pass the key and access the value in the properties file.
There are actually three ways to read the application.properties file,
Using Environment,
#Autowired
Environment environment
environment.getProperty({propertyName})
Or we can use #Value,
#Value("${property}")
but the problem with #Value is it might throw an exception if the value is not in the properties file.
The suggested way is using #ConfigurationProperties
#ConfigurationProperties("userBucket")
public class test{
private String path;
//getters and setters
}
For a detailed example - Reading application.properties.
The best thing is to use the #Value annotation. It will automatically assign a value to your object private Environment en.
This will reduce your code, and it will be easy to filter your files.
There are two ways,
you can directly use #Value in your class
#Value("#{'${application yml field name}'}")
public String ymlField;
Or
To make it clean you can clean #Configuration class where you can add all your #value
#Configuration
public class AppConfig {
#Value("#{'${application yml field name}'}")
public String ymlField;
}
application.yml or application.properties
config.value1: 10
config.value2: 20
config.str: This is a simle str
MyConfig class
#Configuration
#ConfigurationProperties(prefix = "config")
public class MyConfig {
int value1;
int value2;
String str;
public int getValue1() {
return value1;
}
// Add the rest of getters here...
// Values are already mapped in this class. You can access them via getters.
}
Any class that wants to access config values
#Import(MyConfig.class)
class MyClass {
private MyConfig myConfig;
#Autowired
public MyClass(MyConfig myConfig) {
this.myConfig = myConfig;
System.out.println( myConfig.getValue1() );
}
}
The easiest way would be to use the #Value annotation provided by Spring Boot. You need to define a variable at class level. For example:
#Value("${userBucket.path}")
private String userBucketPath
There is another way you can do this via the Environment Class. For example:
Autowire the environment variable to your class where you need to access this property:
#Autowired
private Environment environment
Use the environment variable to get the property value in the line you need it using:
environment.getProperty("userBucket.path");
Hope this answers your question!
To read application.properties or application.yml attributes follow the following steps:
Add your attributes in application.properties or application.yaml
Create config class and add your attributes
application.jwt.secretKey=value
application.jwt.tokenPrefix=value
application.jwt.tokenExpiresAfterDays=value ## 14
application:
jwt:
secret-key: value
token-prefix: value
token-expires-after-days: value ## 14
#Configuration("jwtProperties") // you can leave it empty
#EnableConfigurationProperties
#ConfigurationProperties(prefix = "application.jwt") // prefix is required
public class JwtConfig {
private String secretKey;
private String tokenPrefix;
private int tokenExpiresAfterDays;
// getters and setters
}
NOTE: in .yaml file you have to use kabab-case
Now to use the config class just instantiate it, you can do this manualy or with dependency injection.
public class Target {
private final JwtConfig jwtConfig;
#Autowired
public Target(JwtConfig jwtConfig) {
this.jwtConfig = jwtConfig;
}
// jwtConfig.getSecretKey()
}
For me, none of the above did directly work for me.
I did the following:
In addition to Rodrigo Villalba Zayas' answer, I added implements InitializingBean to the class and implemented the method
#Override
public void afterPropertiesSet() {
String path = env.getProperty("userBucket.path");
}
So that will look like
import org.springframework.core.env.Environment;
public class xyz implements InitializingBean {
#Autowired
private Environment env;
private String path;
....
#Override
public void afterPropertiesSet() {
path = env.getProperty("userBucket.path");
}
public void method() {
System.out.println("Path: " + path);
}
}
I had this problem too. But there is a very simple solution. Just declare your variable in the constructor.
My example:
application.propperties:
#Session
session.timeout=15
SessionServiceImpl class:
private final int SESSION_TIMEOUT;
private final SessionRepository sessionRepository;
#Autowired
public SessionServiceImpl(#Value("${session.timeout}") int sessionTimeout,
SessionRepository sessionRepository) {
this.SESSION_TIMEOUT = sessionTimeout;
this.sessionRepository = sessionRepository;
}
You can use #ConfigurationProperties. It's simple and easy to access a value defined in application.properties:
# Datasource
app.datasource.first.jdbc-url=jdbc:mysql://x.x.x.x:3306/ovtools?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
app.datasource.first.username=
app.datasource.first.password=
app.datasource.first.driver-class-name=com.mysql.cj.jdbc.Driver
server.port=8686
spring.jpa.hibernate.ddl-auto=update
spring.jpa.generate-ddl=true
spring.jpa.show-sql=true
spring.jpa.database=mysql
#Slf4j
#Configuration
public class DataSourceConfig {
#Bean(name = "tracenvDb")
#Primary
#ConfigurationProperties(prefix = "app.datasource.first")
public DataSource mysqlDataSourceanomalie() {
return DataSourceBuilder.create().build();
}
#Bean(name = "JdbcTemplateenv")
public JdbcTemplate jdbcTemplateanomalie(#Qualifier("tracenvDb") DataSource datasourcetracenv) {
return new JdbcTemplate(datasourcetracenv);
}