参数加载器

概念

参数加载器描述了依赖参数如何在对象构造之前被加载,包括但不限于从配置加载、从标签参数加载等等。

参数加载器作为 SD(结构描述符)的一部分,可以被结构提供方定制化,也可以使用自动装载模型提供的默认参数加载器。

默认参数加载器

任何 SD 内定义参数加载器均被优先执行,如果加载失败,则尝试使用默认参数加载器加载。

默认参数加载器被两个基础自动装载模型(singleton、normal)引入。依此采用三种方式加载参数,如果三种方式均加载失败,则抛出错误。

  • 方式1 从标签指向的对象名加载参数,参考 配置文件结构规范

    Load support load struct described like:
    ```go
    normal.RegisterStructDescriptor(&autowire.StructDescriptor{
    		Factory:   func() interface{}{
    			return &Impl{}
    		},
    		ParamFactory: func() interface{}{
    			return &Config{}
    		},
    		ConstructFunc: func(i interface{}, p interface{}) (interface{}, error) {
    			return i, nil
    		},
    	})
    }
    
    type Config struct {
    	Address  string
    	Password string
    	DB       string
    }
    
    ```
    with
    Autowire type 'normal'
    StructName 'Impl'
    Field:
    	MyRedis Redis `normal:"github.com/alibaba/ioc-golang/extension/normal/redis.Impl, redis-1"`
    
    from:
    
    ```yaml
    extension:
      normal:
        github.com/alibaba/ioc-golang/extension/normal/redis.Impl:
            redis-1:
              param:
                address: 127.0.0.1
                password: xxx
                db: 0
    
  • 方式2 从标签加载参数

    Load support load param like:
    ```go
    type Config struct {
    	Address  string
    	Password string
    	DB       string
    }
    ```
    
    from field:
    
    ```go
    NormalRedis  normalRedis.Redis  `normal:"github.com/alibaba/ioc-golang/extension/normal/redis.Impl,address=127.0.0.1&password=xxx&db=0"`
    ```
    
  • 方式3 从配置加载参数,参考 配置文件结构规范

    Load support load struct described like:
    ```go
    normal.RegisterStructDescriptor(&autowire.StructDescriptor{
    		Factory:   func() interface{}{
    			return &Impl{}
    		},
    		ParamFactory: func() interface{}{
    			return &Config{}
    		},
    		ConstructFunc: func(i interface{}, p interface{}) (interface{}, error) {
    			return i, nil
    		},
    	})
    }
    
    type Config struct {
    	Address  string
    	Password string
    	DB       string
    }
    ```
    with
    Autowire type 'normal'
    StructName 'Impl'
    
    from:
    
    ```yaml
    autowire:
      normal:
          github.com/alibaba/ioc-golang/extension/normal/redis.Impl:
            param:
              address: 127.0.0.1
              password: xxx
              db: 0
    

Last modified June 21, 2022: Fix: remove unused file (0fc728c)