如何将SLF4J与Log4J绑定？ [英] How to bind SLF4J with Log4J?

问题描述

我正在尝试用slf4j + log4j设置一个项目，但该死的东西不能正常工作......我一直有异常：

I am trying to setup a project with slf4j + log4j, but the damn thing just doesn't work... I keep getting exception:

Failed to instantiate SLF4J LoggerFactory
Reported exception:
java.lang.NoClassDefFoundError: org/apache/log4j/Level
at org.slf4j.LoggerFactory.bind(LoggerFactory.java:129)
at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108)
at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:302)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:276)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:288)
at TestLog.main(TestLog.java:9)
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Level
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 6 more
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Level
at org.slf4j.LoggerFactory.bind(LoggerFactory.java:129)
at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108)
at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:302)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:276)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:288)
at TestLog.main(TestLog.java:9)
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Level
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 6 more

I检查并且类org.apache.log4j.Level在我的项目Maven Dependencies> log4j-1.2.17.jar下面。 VM为什么不能找到它？

I checked and the class org.apache.log4j.Level is there in my project under "Maven Dependencies > log4j-1.2.17.jar". So why can't the VM find it?

我已经尝试了以下选项：

I tried the below options already:

1. slf4j-api + log4j


2. slf4j-api + slf4j-log4j12


3. slf4j-api + log4j


4. slf4j-api + slf4j-log4j12 + log4j

1. slf4j-api + log4j
2. slf4j-api + slf4j-log4j12
3. slf4j-api + log4j
4. slf4j-api + slf4j-log4j12 + log4j

所有选项均无效：（

这是我的currnet pom.xml：

Here is my currnet pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.sample</groupId>
  <artifactId>DBUnitSample</artifactId>
  <version>1.0</version>

  <dependencies>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.7</version>
    </dependency>

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.7</version>
    </dependency>
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>

  </dependencies>

</project>

另外，我注意到在添加slf4j-log4j12时，它还添加了log4j作为依赖项。树，所以我猜这里明确地添加log4j是多余的，但无论如何我已经添加了它。仍然没有运气。

Also, I noticed that when adding slf4j-log4j12, it adds log4j as a dependency as well in the tree, so I am guessing that adding log4j explicitly here is redundant, but I have added it anyway. Still no luck.

我的主要代码很简单：

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

public class SampleDao {
    private static final Logger log = LoggerFactory.getLogger(SampleDao.class);

    public static void main(String[] args) {
        System.out.println("Hello");
        log.info("Logged");
    }
}

我的log4j.properties：

And my log4j.properties:

log4j.rootLogger=DEBUG, STDOUT
log4j.logger.deng=INFO
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

有人可以告诉我我在做什么错误？我已经尝试在SO上搜索答案，但是所有提到的答案都添加了log4j依赖项，我已经添加了......所以不确定，哪里错了。

Can someone please tell me what am I doing wrong? I already tried searching for answers on SO, but all answers mentioned to add log4j dependency, which I have already added... So not sure, whats wrong.

编辑：这是我的整个项目结构。我点击 SampleDao 并将其作为Java应用程序运行。 （我现在也删除了dbunit依赖，在slf4j问题上为零）

EDIT: Here is my entire project structure. I am R-clicking SampleDao and running it as Java application. ( I have also removed dbunit dependency for now, to zero-in on the slf4j problem)

推荐答案

尝试这些依赖项

Try these dependencies

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.5</version>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>jcl-over-slf4j</artifactId>
    <version>1.7.5</version>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>1.7.5</version>
    <scope>runtime</scope>
</dependency>

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