spring boot初探（二）——springboot配置log4j

spring-boot-starter中默认依赖了spring-boot-starter-logging而他实现的日志组件是Lockback。
事实上官方文档已经讲的非常清楚了，并且提供了两种日志实现的配置Logback和Log4j。具体的官方地址请看:http://docs.spring.io/spring-boot/docs/current/reference/html/howto-logging.html

我们这里主要讲一下如何配置log4j
1、根据官方的方法要想使用log4j，首先得讲默认的log依赖给去除，然后再引入log4j的jar包，pom文件如下:

<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starter-webartifactId>
dependency>

<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starterartifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-loggingartifactId>
        exclusion>
    exclusions>
dependency>

<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starter-log4j2artifactId>
dependency>

注意：如果你想以yml或者json的方式编写配置文件的话（例如：log4j2.yml或者log4j2.json)官方给出了相应的依赖关系

Format	Dependencies	File names
YAML	com.fasterxml.jackson.core:jackson-databind com.fasterxml.jackson.dataformat:jackson-dataformat-yaml	log4j2.yaml log4j2.yml
JSON	com.fasterxml.jackson.core:jackson-databind	log4j2.json log4j2.jsn

所以如果我们想和application.yml配置 文件保持一致的格式的话还需要添加两个依赖:

<dependency>
    <groupId>com.fasterxml.jackson.coregroupId>  
    <artifactId>jackson-databindartifactId>  
dependency>  
<dependency>
    <groupId>com.fasterxml.jackson.dataformatgroupId>  
    <artifactId>jackson-dataformat-yamlartifactId>  
dependency>  

添加如上所示的依赖后我们就可以用log4j2.yml去配置了，接下来就直接贴配置详情了

Configuration:  
  status: warn 

 Properties: # 定义变量  Property: - name: log.path value: d:\\tmp\\logs - name: project.name value: spring-boot-log Appenders: Console: #输出到控制台  name: CONSOLE target: SYSTEM_OUT ThresholdFilter: level: trace onMatch: ACCEPT onMismatch: DENY PatternLayout: pattern: "%d{yyyy-MM-dd HH:mm:ss,SSS}:%4p %t (%F:%L) - %m%n" # 输出到文件，超过128MB归档 RollingFile: - name: ROLLING_FILE ignoreExceptions: false fileName: ${log.path}/${project.name}.log filePattern: "${log.path}/$${date:yyyy-MM}/${project.name}-%d{yyyy-MM-dd}-%i.log.gz" PatternLayout: pattern: "%d{yyyy-MM-dd HH:mm:ss,SSS}:%4p %t (%F:%L) - %m%n" Policies: SizeBasedTriggeringPolicy: size: "128 MB" DefaultRolloverStrategy: max: 1000 Loggers: Root: level: info AppenderRef: - ref: CONSOLE - ref: ROLLING_FILE Logger: # 为com.xjj包配置特殊的Log级别，方便调试  - name: com.test.dao additivity: false level: debug AppenderRef: - ref: CONSOLE - ref: ROLLING_FILE

到这基本上你的log4j2就配置好了。