How to load Name Value property using @ConfigurationProperties in Spring

Question

My property file has a content as follows

config.entry[0]=X-FRAME-OPTIONS,SAMEORIGIN

config.entry[1]=Content-Security-Policy,Frame-Ancestors 'self'

I want this to be loaded to a config class where i can have the comma seperated values loaded as Key,Value pairs in a collection. How can this be achieved using @ConfigurationProperties in Spring 3 ?

Entries = config.getEntry() should give me a collection so that I can iterate and get the list of name value pairs defined in the property file

for(Entry<String,String> index : config.getEntry().entryset()) {
          index.getKey(); // Should Give - X-FRAME-OPTIONS
          index.getValue(); // Should Give - SAMEORIGIN
}

How should i define my Config class that will be autowired with the values from the properties file in this way ?

the following implementation, throws Spring exception "Cannot convert value of type [java.lang.String] to required type [java.util.Map]" for property 'entry[0]': no matching editors or conversion strategy found]

@Component
@ConfigurationProperties("config")
public class MyConfiguration {

  private Map<String,Map<String,String>> entry = new LinkedHashMap<String,Map<String,String>>();

  //getter for entry

  //setter for entry
}

nope, there can be only 1 value per key. I've updated the question with my current approach and the exact error now. — yathirigan
– yathirigan, Commented Apr 28, 2015 at 14:11

Braj · Accepted Answer · 2015-04-28 14:12:16Z

2

You can try with @PostConstruct annotation that will be called after bean in constructed. Here you can load the configuration file and update the map as per your need.

For example:

@Component
public class Config {
    private Map<String, String> entry = new LinkedHashMap<String, String>();

    @PostConstruct
    private void init() throws IOException {
        try (InputStream input = ClassUtils.getDefaultClassLoader().getResourceAsStream("config.properties")) {
            for (String line : IOUtils.readLines(input)) {
                // change the logic as per your need
                String[] keyValue = line.split("=")[1].split(",");
                entry.put(keyValue[0], keyValue[1]);
            }
        }
    }
}

answered Apr 28, 2015 at 14:12

Braj

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8 Comments

yathirigan Over a year ago

doesn't @ConfigurationProperties allow straight forward method for loading this kind of Name-Value pair values ? .. this will be final option

Braj Over a year ago

I don't think so because it's your own custom file that doesn't fit as per the global requirement.

Braj Over a year ago

Is there any issue with this approach? Can you tell me why is it final option?

yathirigan Over a year ago

Spring is taking the entire text as 1 string and creating a Map of that string with 0, 1 as Key. Instead how to force spring to use first part of the text as Key and 2nd part of the text as value.. instead of using the index as Key ?

Braj Over a year ago

why can't you use simple property file with key-value pair? Make it simple.

|

Biju Kunjummen · Accepted Answer · 2015-04-28 16:36:41Z

You can potentially do this in two parts, first a simple @ConfigurationProperties this way:

@ConfigurationProperties(prefix = "config")
@Component
public class SampleConfigProperties {

    private List<String> entry;

    public List<String> getEntry() {
        return entry;
    }

    public void setEntry(List<String> entry) {
        this.entry = entry;
    }
}

This should cleanly load your properties into the entry field of your SampleConfigProperties natively. What you want to do next is not native to Spring - you want the first field in the comma delimited list to be a key in a map, this is a custom logic, you can handle this logic using a @PostConstruct logic this way, see how I am still using Spring's conversionService to transform the comma delimited String to a List<String>:

import javax.annotation.PostConstruct;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@ConfigurationProperties(prefix = "config")
@Component
public class SampleConfigProperties {

    @Autowired
    private ConversionService conversionService;
    private List<String> entry;

    private Map<String, String> entriesMap;


    public List<String> getEntry() {
        return entry;
    }

    public void setEntry(List<String> entry) {
        this.entry = entry;
    }

    public Map<String, String> getEntriesMap() {
        return entriesMap;
    }

    public void setEntriesMap(Map<String, String> entriesMap) {
        this.entriesMap = entriesMap;
    }

    @PostConstruct
    public void postConstruct() {
        Map<String, String> entriesMap = new HashMap<>();
        for (String anEntry: entry) {
            List<String> l = conversionService.convert(anEntry, List.class);
            entriesMap.put(l.get(0), l.get(1));
        }
        this.entriesMap = entriesMap;
    }

}

Need an additional help.The >> List<String> l << is creating a list of string when the string is seperated with coma (,). Is there anyway to force using another seperator character ? like pipe or double pipe...etc ?

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