日志

日志级别：
从高到低分别是 ERROR、WARN、INFO、DEBUG。

解决方案

1.slf4j+logback

image.png

1. 先排除commons-logging
   将依赖commons-logging的包全部排除

<dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <!--            排除commons-loggin-->
            <exclusions>
                <exclusion>
                    <groupId>commons-logging</groupId>
                    <artifactId>commons-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

2. 用中间包来替换原有的日志框架

<dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>jcl-over-slf4j</artifactId><!-- 替换commons-logging-->
       <version>1.7.25</version>
     </dependency> 
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>jul-to-slf4j</artifactId><!-- 替换java.util.logging-->
       <version>1.7.25</version>
</dependency>

日志配置文件

            <!-- 日志 -->
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>${log4j.version}</version>
            </dependency>
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-log4j12</artifactId>
                <version>${slf4j.version}</version>
            </dependency>
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-api</artifactId>
                <version>${slf4j.version}</version>
            </dependency>
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-classic</artifactId>
                <version>${logback.version}</version>
            </dependency>

3. 配置文件logback.xml

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%-4relative [%thread] %-5level %logger{35} - %msg %n</pattern>
        </encoder>
    </appender>

    <root level="INFO">
        <appender-ref ref="STDOUT" />
    </root>

</configuration>

4. 测试使用

public class Slf4j {
    public static void main(String[] args) {
        Logger log = LoggerFactory.getLogger(Slf4j.class);

        //        {} 为占位符，可以接收后面的参数
        log.debug("debug消息 id={},name={}", 1, "zhang");
        log.info("info msg");
        log.warn("warn msg");
        log.error("error msg");

    }
}