如何在SpringBoot应用程序中自动装配具有构造函数和参数的组件 [英] How to Autowire a Component which is having constructor with arguments in SpringBoot Application

问题描述

我有一个带有自动装配构造函数的类.

I have a class having Autowired Constructor.

现在当我在班级中自动装配该班级对象时.如何为构造函数传递参数?

now when i am autowiring this class object in my class. how do i pass arguments for constructor??

示例代码: 具有自动装配构造函数的类:

@Component
public class Transformer {
    private String dataSource;
    @Autowired
    public Transformer(String dataSource)
    {
        this.dataSource = dataSource;
    }
}

使用自动装配的类的具有构造函数并带有参数的组件:

@Component
    public class TransformerUser {
        private String dataSource;
        @Autowired
        public TransformerUser(String dataSource)
        {
            this.dataSource = dataSource;
        }
        @Autowired
        Transformer transformer;

    }

此代码失败，并显示消息

this code fails with message

通过构造函数参数0表示的不满意的依赖关系"

"Unsatisfied dependency expressed through constructor parameter 0"

在创建Transformer类型的bean时.

while creating bean of type Transformer.

我如何在自动装配时将参数传递给Transformer?

how do i pass the arguments to Transformer while Autorwiring it??

推荐答案

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class Transformer {
    private String datasource;

    @Autowired
    public Transformer(String datasource) {
        this.datasource=datasource;
        log.info(datasource);
    }
}

然后创建一个配置文件

package com.example.demo;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class BeanConfig {
    @Bean
    public Transformer getTransformerBean() {
        return new Transformer("hello spring");
    }

    @Bean
    public String getStringBean() {
        return new String();
    }
}

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