Spring .properties file: get element as an Array

问题

I'm loading properties attributes from a .properties file using Spring as follows:

file: elements.properties
base.module.elementToSearch=1
base.module.elementToSearch=2
base.module.elementToSearch=3
base.module.elementToSearch=4
base.module.elementToSearch=5
base.module.elementToSearch=6

The spring xml file

file: myapplication.xml
<bean id="some"
      class="com.some.Class">
      <property name="property" value="#{base.module.elementToSearch}" />
</bean>

And my Class.java

file: Class.java
public void setProperty(final List<Integer> elements){
    this.elements = elements;
}

But when debugging, the parameter elements only get the last element into the list, so, there is a list of one element with value "6", instead of a list with 6 elements.

I tried other approaches, like adding in value only #{base.module} but then it finds no parameter in the properties file.

A workaround is to have in elements.properties file a list separated by commas, like:

base.module.elementToSearch=1,2,3,4,5,6

and use it as a String and parse it, but is there a better solution?

回答1:

If you define your array in properties file like:

base.module.elementToSearch=1,2,3,4,5,6

You can load such array in your Java class like this:

  @Value("${base.module.elementToSearch}")
  private String[] elementToSearch;

回答2:

And incase you a different delimiter other than comma, you can use that as well.

@Value("#{'${my.config.values}'.split(',')}")
private String[] myValues;   // could also be a List<String>

and

in your application properties you could have

my.config.values=value1, value2, value3

回答3:

Here is an example of how you can do it in Spring 4.0+

application.properties content:

some.key=yes,no,cancel

Java Code:

@Autowire
private Environment env;

...

String[] springRocks = env.getProperty("some.key", String[].class);

回答4:

With a Spring Boot one can do the following:

application.properties

values[0]=abc
values[1]=def

Configuration class

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.List;

@Component
@ConfigurationProperties
public class Configuration {

    List<String> values = new ArrayList<>();

    public List<String> getValues() {
        return values;
    }

}

This is needed, without this class or without the values in class it is not working.

Spring Boot Application class

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.util.List;

@SpringBootApplication
public class SpringBootConsoleApplication implements CommandLineRunner {

    private static Logger LOG = LoggerFactory.getLogger(SpringBootConsoleApplication.class);

    // notice #{} is used instead of ${}
    @Value("#{configuration.values}")
    List<String> values;

    public static void main(String[] args) {
        SpringApplication.run(SpringBootConsoleApplication.class, args);
    }

    @Override
    public void run(String... args) {
        LOG.info("values: {}", values);
    }

}

来源：https://stackoverflow.com/questions/6212898/spring-properties-file-get-element-as-an-array