【JAVA】日志管理slf4j

前言

这边文章描述怎么使用slf4j.

1.使用步骤

a.maven导入依赖

    <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.5</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.5</version>
      <!-- <scope>test</scope> -->
    </dependency>

b.在resources路径下添加配置文件  log4j.properties

### 设置###
log4j.rootLogger=debug,stdout,D,E
### 输出信息到控制抬 ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n
### 输出DEBUG 级别以上的日志到=E://logs/error.log ###
log4j.appender.D=org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File=D://logs/log.log
log4j.appender.D.Append=true
log4j.appender.D.Threshold=DEBUG
log4j.appender.D.layout=org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss}  [ %t:%r ] - [ %p ]  %m%n
### 输出ERROR 级别以上的日志到=E://logs/error.log ###
log4j.appender.E=org.apache.log4j.DailyRollingFileAppender
log4j.appender.E.File=D://logs/error.log
log4j.appender.E.Append=true
log4j.appender.E.Threshold=ERROR
log4j.appender.E.layout=org.apache.log4j.PatternLayout
log4j.appender.E.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss}  [ %t:%r ] - [ %p ]  %m%n

c.添加java代码

public class Log4jTestDemo {

  private static Logger logger = LoggerFactory.getLogger(Log4jTestDemo.class);

  public static void main(String[] args) {
    System.out.println("This is println message.");

    // 记录debug级别的信息
    logger.debug("This is debug message.");
    // 记录info级别的信息
    logger.info("This is info message.");
    // 记录error级别的信息
    logger.error("This is error message.");
  }
}

2.常见的问题

a.提示下面错误

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

原因是因为导入maven时没有导入

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.5</version>
      <!-- <scope>test</scope> -->
    </dependency>