slf4j集成log4j
所属分类 slf4j
浏览量 1233
slf4j 支持占位符号
添加依赖
org.slf4j
slf4j-log4j12
1.7.20
log4j 和 slf4j-api 会简介依赖进来
mvn dependency:tree -Dverbose
[INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ logerror ---
[INFO] dyyx:logerror:jar:1.0
[INFO] \- org.slf4j:slf4j-log4j12:jar:1.7.20:compile
[INFO] +- org.slf4j:slf4j-api:jar:1.7.20:compile
[INFO] \- log4j:log4j:jar:1.2.17:compile
增加log4j配置 log4j.properties
log4j.rootLogger=DEBUG, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n
log4j.properties 不存在则打印warn信息
log4j:WARN No appenders could be found for logger (dyyx.Hello).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
测试代码
import java.util.Date;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Hello {
public static void main(String[] args) throws Exception {
// System.out.println("hello");
Logger log = LoggerFactory.getLogger(Hello.class);
log.error("error,"+new Date());
log.info("hello,{}","tiger");
}
}
ERROR [main] (Hello.java:11) - error,Mon Jun 10 12:55:33 CST 2019
INFO [main] (Hello.java:12) - hello,tiger
日志静态绑定
org/slf4j/impl/StaticLoggerBinder.class
public static Logger getLogger(String name) {
ILoggerFactory iLoggerFactory = getILoggerFactory();
return iLoggerFactory.getLogger(name);
}
LoggerFactory.bind()
private final static void bind() {
try {
Set staticLoggerBinderPathSet = null;
// skip check under android, see also http://jira.qos.ch/browse/SLF4J-328
if (!isAndroid()) {
staticLoggerBinderPathSet = findPossibleStaticLoggerBinderPathSet();
reportMultipleBindingAmbiguity(staticLoggerBinderPathSet);
}
// the next line does the binding
StaticLoggerBinder.getSingleton();
INITIALIZATION_STATE = SUCCESSFUL_INITIALIZATION;
reportActualBinding(staticLoggerBinderPathSet);
replayEvents();
} catch (NoClassDefFoundError ncde) {
String msg = ncde.getMessage();
if (messageContainsOrgSlf4jImplStaticLoggerBinder(msg)) {
INITIALIZATION_STATE = NOP_FALLBACK_INITIALIZATION;
Util.report("Failed to load class \"org.slf4j.impl.StaticLoggerBinder\".");
Util.report("Defaulting to no-operation (NOP) logger implementation");
Util.report("See " + NO_STATICLOGGERBINDER_URL + " for further details.");
} else {
failedBinding(ncde);
throw ncde;
}
} catch (java.lang.NoSuchMethodError nsme) {
String msg = nsme.getMessage();
if (msg != null && msg.contains("org.slf4j.impl.StaticLoggerBinder.getSingleton()")) {
INITIALIZATION_STATE = FAILED_INITIALIZATION;
Util.report("slf4j-api 1.6.x (or later) is incompatible with this binding.");
Util.report("Your binding is version 1.5.5 or earlier.");
Util.report("Upgrade your binding to version 1.6.x.");
}
throw nsme;
} catch (Exception e) {
failedBinding(e);
throw new IllegalStateException("Unexpected initialization failure", e);
}
}
扫描 org.slf4j.impl.StaticLoggerBinder
有多个话 ,只能绑定一个
该类不存在
StaticLoggerBinder.getSingleton() 不存在
其他绑定异常
slf4j-log4j12/1.7.20
StaticLoggerBinder
private StaticLoggerBinder() {
loggerFactory = new Log4jLoggerFactory();
try {
@SuppressWarnings("unused")
Level level = Level.TRACE;
} catch (NoSuchFieldError nsfe) {
Util.report("This version of SLF4J requires log4j version 1.2.12 or later. See also http://www.slf4j.org/codes.html#log4j_version");
}
}
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