slf4j 的 桥接器和适配器

1.桥接器

        A. log4j --> slf4j
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>log4j-over-slf4j</artifactId>
            <version>2.0.0-alpha1</version>
        </dependency>

       B. log4j2 --->slf4j
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-to-slf4j</artifactId>
            <version>2.14.1</version>
        </dependency>

       C. jul--->slf4j
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jul-to-slf4j</artifactId>
            <version>2.0.0-alpha1</version>
        </dependency>
      
       D. jcl --->slf4j
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>2.0.0-alpha1</version>
        </dependency>

A. log4j-over-slf4j 桥接方式，定义一套和log4j 一样的api ，在这套api中 再调用slf4j的api
app ---> log4j-over-slf4j --->slf4j-api

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B. log4j-to-slf4j 的桥接方式 使用了spi 标准， 此处slf4j 是作为适配器存在的
app --->log4j-api-2.X ---> log4j-to-slf4j --->slf4j-api
所以 log4j-api-2.X 这个包是必须的，不可剔除

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2.适配器(也就是具体的日志记录策略)

     A. jul
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-jdk14</artifactId>
            <version>2.0.0-alpha1</version>
        </dependency>

    B. log4j
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>2.0.0-alpha1</version>
        </dependency>
      
    C.log4j2
         <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-slf4j-impl</artifactId>
            <version>2.14.1</version>
        </dependency>

    D. logback
         <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.3.0-alpha5</version>
        </dependency>

3.具体实现

B. log4j
         <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

C.log4j2
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.14.1</version>
        </dependency>