如何在 Spring boot 中使用构造函数注入为不同的属性值创建相同的 Bean

Question

I have to create multiple beans of same type for different property value which is to be injected using constructor.

Currently I have used Bean scope as Prototype & created multiple methods to read different properties to create new object. How to combine all the different methods into single method and to supply different values at run time to create new bean.

    package com.demo.service;

    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.core.env.Environment;

    @Configuration
    public class ConfigClass {


@Bean(name="RC")
public JavaClient getClient(@Autowired Environment env)
{
    String sName=env.getProperty("RCSName");
    String aUrl=env.getProperty("RCAUrl");
    String dUrl=env.getProperty("RCDUrl");
    return new JavaClient(sName,aUrl,dUrl);
}

@Bean(name="O")
public JavaClient getOClient(@Autowired Environment env)
{
    String sName=env.getProperty("OSName");
    String aUrl=env.getProperty("OAUrl");
    String dUrl=env.getProperty("ODUrl");
    return new JavaClient(sName,aUrl,dUrl);
}

}

Now it is creating 2 beans as per above code. Expectation: How to combine getClient & getOClient into single method, but the property to be supplied in a loop to create multiple beans of same type JavaClient

Answer 1

I have modified my ConfigClass as below & created ApplicationContextAware to inject beans by reading file properties.

    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.Scope;
    import org.springframework.scheduling.annotation.EnableScheduling;


    @Configuration
    @EnableScheduling
    public class ConfigClass {

        @Bean
        @Scope("prototype")
        public JavaClient getClient(String sName,String aUrl,String dUrl)
        {
            return new JavaClient(sName,aUrl,dUrl);
        }
    }

Then Have created ApplicationContextAware to create Beans.

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.Iterator;
import java.util.List;

import javax.annotation.PostConstruct;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Component;



@Component
public class ApplicationContextProvider implements ApplicationContextAware {

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;

    } 

    public ApplicationContext getContext() {
        return applicationContext;
    }

    @PostConstruct
    public void init()
    {
        try {
            String fileName = "Url.txt";
               Resource resource = new ClassPathResource(fileName);
               File file = resource.getFile();

               List<String> lines = Files.readAllLines(file.toPath());

                for (Iterator<String> iterator = lines.iterator(); iterator.hasNext();) {
                    String line = (String) iterator.next();
                    String[] s = line.split(",");
                    applicationContext.getBean(JavaClient.class,s[0], s[1], s[2]);

                }
            } catch (IOException e) {
                e.printStackTrace();
        }
    }

}