实现log4j打印日志依赖的jar包共3个，在pom.xml中加入相关依赖：
<!-- 添加log4j日志相关jar包:共3个jar--> <!-- https://mvnrepository.com/artifact/log4j/log4j --> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency> <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>1.7.25</version> </dependency> <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.7.25</version> <scope>test</scope> </dependency>第二步，在项目的 src/test/resource目录下新建log4j.properties文件，文件内容为：
### set log levels ### log4j.rootLogger = debug,stdout,R ### console appender### log4j.appender.stdout = org.apache.log4j.ConsoleAppender log4j.appender.stdout.Target = System.out log4j.appender.stdout.Threshold = Info log4j.appender.stdout.layout = org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern = %d [%t] %p [%c] - %m%n ### output to files ### log4j.appender.R = org.apache.log4j.DailyRollingFileAppender log4j.appender.R.File = logs/log.txt log4j.appender.R.Append = true log4j.appender.R.Threshold = Info log4j.appender.R.layout = org.apache.log4j.PatternLayout #log4j.appender.R.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss}-[%p]%m%n log4j.appender.R.layout.ConversionPattern = %d [%t] %p [%c] - %m%n