讓你的spring-boot應用日誌爲所欲爲--spring boot日誌深刻分析

時間 2020-11-01

標籤 html java web spring sql express apache bootstrap tomcat app 欄目 Spring 简体版

原文原文鏈接

1.spring boot日誌概述html

spring boot使用Commons Logging做爲內部的日誌系統，而且給Java Util Logging，Log4J2以及Logback都提供了默認的配置。
若是使用了spring boot的Starters，那麼默認會使用Logback用於記錄日誌。java

2.spring boot日誌默認配置web

咱們啓動一個空的spring-boot項目看一下控制檯的日誌spring

控制檯的默認配置sql

logging.pattern.console=%clr(%d{${LOG_DATEFORMAT_PATTERN:-yyyy-MM-dd HH:mm:ss.SSS}}){faint} %clr(${LOG_LEVEL_PATTERN:-%5p}) %clr(${PID:- }){magenta} %clr(---){faint} %clr([%15.15t]){faint} %clr(%-40.40logger{39}){cyan} %clr(:){faint} %m%n${LOG_EXCEPTION_CONVERSION_WORD:-%wEx}
其中%clr爲配置不一樣的顏色輸出，支持的顏色有如下幾種：express

blue
cyan
faint
green
magenta
red
yellow
輸出順序分析：apache

一、日期和時間--精確到毫秒，並按照時間進行簡單的排序，格式爲：bootstrap

%clr(%d{${LOG_DATEFORMAT_PATTERN:-yyyy-MM-dd HH:mm:ss.SSS}}){faint}tomcat

二、日誌級別--ERROR,WARN,INFO,DEBUG,TRACEapp

%clr(${LOG_LEVEL_PATTERN:-%5p})

三、進程ID號

%clr(${PID:- })

四、日誌內容，用"---"分隔符分開

%clr(---){faint}

五、線程名字--括在方括號中

%clr([%15.15t]){faint}

六、日誌的名字--一般對應的是類名

%clr(%-40.40logger{39}){cyan}
注意：Logback沒有FATAL級別（映射到ERROR）

不一樣日誌級別對應的顏色以下

3.spring boot日誌配置

能夠經過application.properties或者application.yml查看全部配置

每一個配置後面都有說明，就不一一贅述了。

4.spring boot日誌實現原理

點擊配置屬性，能夠進入LoggingApplicationListener這個類，

`/**

An {@link ApplicationListener} that configures the {@link LoggingSystem}. If the
environment contains a {@code logging.config} property it will be used to bootstrap the
logging system, otherwise a default configuration is used. Regardless, logging levels
will be customized if the environment contains {@code logging.level.*} entries and
logging groups can be defined with {@code logging.group}.
<p>
Debug and trace logging for Spring, Tomcat, Jetty and Hibernate will be enabled when
the environment contains {@code debug} or {@code trace} properties that aren't set to
{@code "false"} (i.e. if you start your application using
{@literal java -jar myapp.jar [--debug | --trace]}). If you prefer to ignore these
properties you can set {@link #setParseArgs(boolean) parseArgs} to {@code false}.
<p>
By default, log output is only written to the console. If a log file is required the
{@code logging.path} and {@code logging.file} properties can be used.
<p>
Some system properties may be set as side effects, and these can be useful if the
logging configuration supports placeholders (i.e. log4j or logback):
<ul>
<li>{@code LOG_FILE} is set to the value of path of the log file that should be written
(if any).</li>
<li>{@code PID} is set to the value of the current process ID if it can be determined.
</li>
</ul>
@author Dave Syer
@author Phillip Webb
@author Andy Wilkinson
@author Madhura Bhave
@since 2.0.0
@see LoggingSystem#get(ClassLoader)
*/`

它實現了GenericApplicationListener接口，它默認定義了日誌組DEFAULT_GROUP_LOGGERS和日誌級別LOG_LEVEL_LOGGERS

private static final Map<String, List<String>> DEFAULT_GROUP_LOGGERS;
    static {
        MultiValueMap<String, String> loggers = new LinkedMultiValueMap<>();
        loggers.add("web", "org.springframework.core.codec");
        loggers.add("web", "org.springframework.http");
        loggers.add("web", "org.springframework.web");
        loggers.add("web", "org.springframework.boot.actuate.endpoint.web");
        loggers.add("web",
                "org.springframework.boot.web.servlet.ServletContextInitializerBeans");
        loggers.add("sql", "org.springframework.jdbc.core");
        loggers.add("sql", "org.hibernate.SQL");
        DEFAULT_GROUP_LOGGERS = Collections.unmodifiableMap(loggers);
    }

    private static final Map<LogLevel, List<String>> LOG_LEVEL_LOGGERS;
    static {
        MultiValueMap<LogLevel, String> loggers = new LinkedMultiValueMap<>();
        loggers.add(LogLevel.DEBUG, "sql");
        loggers.add(LogLevel.DEBUG, "web");
        loggers.add(LogLevel.DEBUG, "org.springframework.boot");
        loggers.add(LogLevel.TRACE, "org.springframework");
        loggers.add(LogLevel.TRACE, "org.apache.tomcat");
        loggers.add(LogLevel.TRACE, "org.apache.catalina");
        loggers.add(LogLevel.TRACE, "org.eclipse.jetty");
        loggers.add(LogLevel.TRACE, "org.hibernate.tool.hbm2ddl");
        LOG_LEVEL_LOGGERS = Collections.unmodifiableMap(loggers);
    }

你也能夠自定義logging.level和logging.group,它們都是map結構。LoggingApplicationListener重寫了onApplicationEvent方法，實現日誌的打印

@Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ApplicationStartingEvent) {
            onApplicationStartingEvent((ApplicationStartingEvent) event); //1
        }
        else if (event instanceof ApplicationEnvironmentPreparedEvent) {
            onApplicationEnvironmentPreparedEvent(
                    (ApplicationEnvironmentPreparedEvent) event); //2 
        }
        else if (event instanceof ApplicationPreparedEvent) {
            onApplicationPreparedEvent((ApplicationPreparedEvent) event); //3
        }
        else if (event instanceof ContextClosedEvent && ((ContextClosedEvent) event)
                .getApplicationContext().getParent() == null) {
            onContextClosedEvent();  //4
        }
        else if (event instanceof ApplicationFailedEvent) {
            onApplicationFailedEvent();  //5
        }
    }

第一步：根據classloader里加載的依賴決定使用哪一個日誌系統？

主要實現有JavaLoggingSystem，Log4J2LoggingSystem，LogbackLoggingSystem

private void onApplicationStartingEvent(ApplicationStartingEvent event) {
        this.loggingSystem = LoggingSystem
                .get(event.getSpringApplication().getClassLoader());
        this.loggingSystem.beforeInitialize();
    }

第二步：經過classpath，enviroment等獲取參數初始化日誌系統

/**
     * Initialize the logging system according to preferences expressed through the
     * {@link Environment} and the classpath.
     * @param environment the environment
     * @param classLoader the classloader
     */
    protected void initialize(ConfigurableEnvironment environment,
            ClassLoader classLoader) {
        new LoggingSystemProperties(environment).apply();
        LogFile logFile = LogFile.get(environment);
        if (logFile != null) {
            logFile.applyToSystemProperties();
        }
        initializeEarlyLoggingLevel(environment);
        initializeSystem(environment, this.loggingSystem, logFile);
        initializeFinalLoggingLevels(environment, this.loggingSystem);
        registerShutdownHookIfNecessary(environment, this.loggingSystem);
    }

第三步：註冊springBootLoggingSystem

private void onApplicationPreparedEvent(ApplicationPreparedEvent event) {
        ConfigurableListableBeanFactory beanFactory = event.getApplicationContext()
                .getBeanFactory();
        if (!beanFactory.containsBean(LOGGING_SYSTEM_BEAN_NAME)) {
            beanFactory.registerSingleton(LOGGING_SYSTEM_BEAN_NAME, this.loggingSystem);
        }
    }

第四步和第五步：日誌系統清洗

private void onContextClosedEvent() {
        if (this.loggingSystem != null) {
            this.loggingSystem.cleanUp();
        }
    }

    private void onApplicationFailedEvent() {
        if (this.loggingSystem != null) {
            this.loggingSystem.cleanUp();
        }
    }

5.自定義配置文件

日誌系統自定義配置文件
Logback

logback-spring.xml, logback-spring.groovy, logback.xml, or logback.groovy

Log4j2

log4j2-spring.xml or log4j2.xml

JDK (Java Util Logging)

logging.properties

6.總結

　　spring boot日誌系統封裝了logback，log4j2和java log，默認狀況下使用java log，一旦使用各類starts，則默認使用Log4J2，也能夠經過classpath來改變，pom.xml指定

<dependency> 
 <groupId>org.springframework.boot</groupId> 
 <artifactId>spring-boot-starter</artifactId> 
 <exclusions> 
  <exclusion> 
   <groupId>org.springframework.boot</groupId> 
   <artifactId>spring-boot-starter-logging</artifactId> 
  </exclusion> 
 </exclusions> 
</dependency> 
<dependency> 
 <groupId>org.springframework.boot</groupId> 
 <artifactId>spring-boot-starter-log4j</artifactId> 
</dependency>