org.slf4j:slf4j-api:1.7.25
org.slf4j:slf4j-simple:1.7.25

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

final Logger log = LoggerFactory.getLogger("demo");
log.info("hello,slf4j,info");
log.debug("hello,slf4j,debug");

去掉 依赖 slf4j-simple

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.

java.lang.NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder

static final NOPLoggerFactory NOP_FALLBACK_FACTORY = new NOPLoggerFactory();


项目里增加
org.slf4j.impl.MyLoggerFactory
org.slf4j.impl.StaticLoggerBinder.java:6

存在多个

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [file:/Users/dugang/dugang/my/work2024/demo/slf4jdemo/target/classes/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/Users/dugang/.m2/repository/org/slf4j/slf4j-simple/1.7.25/slf4j-simple-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.MyLoggerFactory]


可注释掉 项目里的 StaticLoggerBinder



private static String STATIC_LOGGER_BINDER_PATH = "org/slf4j/impl/StaticLoggerBinder.class";


Set< URL> staticLoggerBinderPathSet = new LinkedHashSet();
        try {
            ClassLoader loggerFactoryClassLoader = LoggerFactory.class.getClassLoader();
            Enumeration paths;
            if (loggerFactoryClassLoader == null) {
                paths = ClassLoader.getSystemResources(STATIC_LOGGER_BINDER_PATH);
            } else {
                paths = loggerFactoryClassLoader.getResources(STATIC_LOGGER_BINDER_PATH);
            }
            while (paths.hasMoreElements()) {
                URL path = paths.nextElement();
                staticLoggerBinderPathSet.add(path);
            }
        } catch (IOException ioe) {
            Util.report("Error getting resources from path", ioe);
        }



System.out.println(LoggerFactory.getILoggerFactory().getClass());
class org.slf4j.impl.MyLoggerFactory
class org.slf4j.impl.SimpleLoggerFactory




初始化状态

    static final int UNINITIALIZED = 0;
    static final int ONGOING_INITIALIZATION = 1;
    static final int FAILED_INITIALIZATION = 2;
    static final int SUCCESSFUL_INITIALIZATION = 3;
    static final int NOP_FALLBACK_INITIALIZATION = 4;

    static volatile int INITIALIZATION_STATE = UNINITIALIZED;

 


 package org.slf4j.impl;

 import org.slf4j.ILoggerFactory;
 import org.slf4j.Logger;
 import org.slf4j.helpers.NOPLogger;

 public class MyLoggerFactory implements ILoggerFactory {
     public Logger getLogger(String name){
         return NOPLogger.NOP_LOGGER;
     }

 }



package org.slf4j.impl;

import org.slf4j.ILoggerFactory;


public class StaticLoggerBinder {

    private static final StaticLoggerBinder SINGLETON = new StaticLoggerBinder();
    private static final String loggerFactoryClassStr = MyLoggerFactory.class.getName();
    private final ILoggerFactory loggerFactory = new MyLoggerFactory();
    public static final StaticLoggerBinder getSingleton() {return SINGLETON;}
    private StaticLoggerBinder() {}
    public ILoggerFactory getLoggerFactory() {return this.loggerFactory;}
    public String getLoggerFactoryClassStr() {return loggerFactoryClassStr;}
}




https://gitee.com/dyyx/work2024/tree/master/demo/slf4jdemo