1, the log frame
Sally; the development of a large-scale system;
1, System.out.println ( ""); the key data printed on the console; removed? Written in a file?
2, run-time framework to record some of the information systems; logging framework; zhanglogging.jar;
3, several functions on tall? Asynchronous mode? Automatic archiving? xxxx? zhanglogging-good.jar?
4, the previous frame unload? Put a new framework for revising the relevant API before; zhanglogging-prefect.jar;
5, JDBC database driver ---;
write a unified interface layer; log facade (a layer of abstraction log); logging-abstract. jar;
import projects to achieve specific log on the line; abstraction layer logging framework before we are achievable;
logging framework on the market;
JUL, JCL, Jboss-logging, logback, log4j, log4j2, SLF4J ....
Is selected from a left side of the facade (abstraction layer), to choose the right one implementation;
log facade: SLF4J;
log achieved: Logback;
SpringBoot: bottom layer is the Spring framework, Spring framework default is the JCL; '
SpringBoot SLF4j selection and the logback;
2, SLF4j use
1, how to use the system SLF4j https://www.slf4j.org
later developed when logging method calls should not directly implement the class to call log, but logs abstraction layer which method call;
the system slf4j introduced inside the jar and the jar achieved logback
import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class HelloWorld { public static void main(String[] args) { Logger logger = LoggerFactory.getLogger(HelloWorld.class); logger.info("Hello World"); } }
Icon;
Implementation framework Each log has its own configuration file. SLF4J later use, or profiles made of the log itself implement frame profile
member;
2, legacy
a (slf4j + logback): Spring (commons-logging), Hibernate (jboss-logging), MyBatis, xxxx
unified logging even the other with a unified framework and I use slf4j output?
How to get all the logs systems are unified to slf4j;
1, the system will first exclude other logging framework;
2, with the middle package to replace the existing logging framework;
3, we import other implementations slf4j
3, SpringBoot log relationship
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring‐boot‐starter</artifactId> </dependency>
SpringBoot使用它来做日志功能；
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring‐boot‐starter‐logging</artifactId> </dependency>
底层依赖关系
总结：
1）、SpringBoot底层也是使用slf4j+logback的方式进行日志记录
2）、SpringBoot也把其他的日志都替换成了slf4j；
3）、中间替换包？
@SuppressWarnings("rawtypes")
public abstract class LogFactory {
static String UNSUPPORTED_OPERATION_IN_JCL_OVER_SLF4J =
"http://www.slf4j.org/codes.html#unsupported_operation_in_jcl_over_slf4j";
static LogFactory logFactory = new SLF4JLogFactory();
4）、如果我们要引入其他框架？一定要把这个框架的默认日志依赖移除掉？
Spring框架用的是commons-logging；
<dependency> <groupId>org.springframework</groupId> <artifactId>spring‐core</artifactId> <exclusions> <exclusion> <groupId>commons‐logging</groupId> <artifactId>commons‐logging</artifactId> </exclusion> </exclusions> </dependency>
SpringBoot能自动适配所有的日志，而且底层使用slf4j+logback的方式记录日志，引入其他框架的时候，只需要
把这个框架依赖的日志框架排除掉即可；
4、日志使用
1、默认配置
SpringBoot默认帮我们配置好了日志；
//记录器 Logger logger = LoggerFactory.getLogger(getClass()); @Test public void contextLoads() { //System.out.println(); //日志的级别； //由低到高 trace<debug<info<warn<error //可以调整输出的日志级别；日志就只会在这个级别以以后的高级别生效 logger.trace("这是trace日志..."); logger.debug("这是debug日志..."); //SpringBoot默认给我们使用的是info级别的，没有指定级别的就用SpringBoot默认规定的级别；root级别 logger.info("这是info日志..."); logger.warn("这是warn日志..."); logger.error("这是error日志..."); }
日志输出格式： %d表示日期时间， %thread表示线程名， %‐5level：级别从左显示5个字符宽度 %logger{50} 表示logger名字最长50个字符，否则按照句点分割。 %msg：日志消息， %n是换行符 ‐‐> %d{yyyy‐MM‐dd HH:mm:ss.SSS} [%thread] %‐5level %logger{50} ‐ %msg%n
SpringBoot修改日志的默认配置
logging.level.com.atguigu=trace #logging.path= # 不指定路径在当前项目下生成springboot.log日志 # 可以指定完整的路径； #logging.file=G:/springboot.log # 在当前磁盘的根路径下创建spring文件夹和里面的log文件夹；使用 spring.log 作为默认文件 logging.path=/spring/log # 在控制台输出的日志的格式 logging.pattern.console=%d{yyyy‐MM‐dd} [%thread] %‐5level %logger{50} ‐ %msg%n # 指定文件中日志输出的格式 logging.pattern.file=%d{yyyy‐MM‐dd} === [%thread] === %‐5level === %logger{50} ==== %msg%n
2、指定配置
给类路径下放上每个日志框架自己的配置文件即可；SpringBoot就不使用他默认配置的了
logback.xml：直接就被日志框架识别了；
logback-spring.xml：日志框架就不直接加载日志的配置项，由SpringBoot解析日志配置，可以使用SpringBoot
的高级Profile功能
<springProfile name="staging">
<!‐‐ configuration to be enabled when the "staging" profile is active ‐‐>
可以指定某段配置只在某个环境下生效
</springProfile>
如：
<appender name="stdout" class="ch.qos.logback.core.ConsoleAppender"> <!‐‐ 日志输出格式： %d表示日期时间， %thread表示线程名， %‐5level：级别从左显示5个字符宽度 %logger{50} 表示logger名字最长50个字符，否则按照句点分割。 %msg：日志消息， %n是换行符 ‐‐> <layout class="ch.qos.logback.classic.PatternLayout"> <springProfile name="dev"> <pattern>%d{yyyy‐MM‐dd HH:mm:ss.SSS} ‐‐‐‐> [%thread] ‐‐‐> %‐5level %logger{50} ‐ %msg%n</pattern> </springProfile> <springProfile name="!dev"> <pattern>%d{yyyy‐MM‐dd HH:mm:ss.SSS} ==== [%thread] ==== %‐5level %logger{50} ‐ %msg%n</pattern> </springProfile> </layout> </appender>
如果使用logback.xml作为日志配置文件，还要使用profile功能，会有以下错误
no applicable action for [springProfile]
5、切换日志框架
可以按照slf4j的日志适配图，进行相关的切换；
slf4j+log4j的方式；
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring‐boot‐starter‐web</artifactId> <exclusions> <exclusion> <artifactId>logback‐classic</artifactId> <groupId>ch.qos.logback</groupId> </exclusion> <exclusion> <artifactId>log4j‐over‐slf4j</artifactId> <groupId>org.slf4j</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j‐log4j12</artifactId> </dependency>
切换为log4j2
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring‐boot‐starter‐web</artifactId> <exclusions> <exclusion> <artifactId>spring‐boot‐starter‐logging</artifactId> <groupId>org.springframework.boot</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring‐boot‐starter‐log4j2</artifactId> </dependency>