How to fetch file from azure blob using spring boot

Question

I want to fetch files from Azure blob storage. Following code does it fine-

package com.<your-resource-group>.<your-artifact-name>;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.Resource;
import org.springframework.core.io.WritableResource;
import org.springframework.util.StreamUtils;
import org.springframework.web.bind.annotation.*;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;

@RestController
@RequestMapping("blob")
public class BlobController {

    @Value("azure-blob://<your-container-name>/<your-blob-name>")
    private Resource blobFile;

    @GetMapping("/readBlobFile")
    public String readBlobFile() throws IOException {
        return StreamUtils.copyToString(
                this.blobFile.getInputStream(),
                Charset.defaultCharset());
    }

    @PostMapping("/writeBlobFile")
    public String writeBlobFile(@RequestBody String data) throws IOException {
        try (OutputStream os = ((WritableResource) this.blobFile).getOutputStream()) {
            os.write(data.getBytes());
        }
        return "file was updated";
    }
}

My Question -

The @Value annotation provides value to the Resource that is static (i.e I cannot put any variable containing my path as a string inside @Value).

How can I implement the this

Answer 1

In application properties try storing the path

#application.properties
blob.path=

We can use @Value("${...property's name}") annotation to access the above property in the Java class as follows:

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ValueController {

    @Value("${blob.path}") 
    private String path;

    @GetMapping("")
    ..
    }
}

Here try to use blob uri complete path in application properties and use the same in @value annotation as variable by map datatype

//
    @Value("${blob.path}") 
private Map<String, String>  blobPath;

See this > java - How to read external properties based on value of local variable in Spring Boot? - Stack Overflow & Value Spring: Spring @Value annotation tricks - DEV Community

Also see Requestmapping

Other references :

1. Spring Azure Blob Storage | DevGlan
2. spring batch - How to read the csv files from Azure Blob Storage in Java with folder structure as 'dir1 / dir2 / dir3 /..'? - Stack Overflow