无法实例化SLF4J LoggerFactory

本文介绍了无法实例化SLF4J LoggerFactory的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

所以

我正在使用此示例 BONECP :

package javasampleapps; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import com.jolbox.bonecp.BoneCP; import com.jolbox.bonecp.BoneCPConfig; /** A test project demonstrating the use of BoneCP in a JDBC environment. * @author wwadge */ public class BoneCPExample { /** Start test * @param args none expected. */ public static void main(String[] args) { BoneCP connectionPool = null; Connection connection = null; try { // load the database driver (make sure this is in your classpath!) Class.forName("com.mysql.jdbc.Driver"); } catch (Exception e) { e.printStackTrace(); return; } try { // setup the connection pool BoneCPConfig config = new BoneCPConfig(); config.setJdbcUrl("jdbc:mysql://domain/db"); config.setUsername("root"); config.setPassword("pass"); config.setMinConnectionsPerPartition(5); config.setMaxConnectionsPerPartition(10); config.setPartitionCount(1); connectionPool = new BoneCP(config); // setup the connection pool connection = connectionPool.getConnection(); // fetch a connection if (connection != null){ System.out.println("Connection successful!"); Statement stmt = connection.createStatement(); ResultSet rs = stmt.executeQuery("SELECT id from batches limit 1"); // do something with the connection. while(rs.next()){ System.out.println(rs.getString(1)); // should print out "1"' } } connectionPool.shutdown(); // shutdown connection pool. } catch (SQLException e) { e.printStackTrace(); } finally { if (connection != null) { try { connection.close(); } catch (SQLException e) { e.printStackTrace(); } } } } }

我在netbeans的库"菜单中添加了slf4j， D:/Documents%20and%20Settings/DavidH/My%20Documents/NetBeansProjects/jars/slf4j-api-1.6.4.jar 和 D:/Documents%20and%20Settings/DavidH/My%20Documents/NetBeansProjects/jars/slf4j-log4j12-1.6.4.jar 到图书馆.

I added slf4j in my Libraries menu in netbeans, adding D:/Documents%20and%20Settings/DavidH/My%20Documents/NetBeansProjects/jars/slf4j-api-1.6.4.jar and D:/Documents%20and%20Settings/DavidH/My%20Documents/NetBeansProjects/jars/slf4j-log4j12-1.6.4.jar to the library.

然后，我制作了一个Google Guava库，并将他们为此分发的jar添加到另一个库中.

Then I made a Google Guava library and added the jar that they distribute for that to another library.

然后我将两个库都添加到项目中，然后运行.

I then added both of the libraries to the project and hit run.

我现在收到此错误:

Failed to instantiate SLF4J LoggerFactory Reported exception: java.lang.NoClassDefFoundError: org/apache/log4j/Level at org.slf4j.LoggerFactory.bind(LoggerFactory.java:128) at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108) at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:279) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:252) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:265) at com.jolbox.bonecp.BoneCPConfig.<clinit>(BoneCPConfig.java:60) at javasampleapps.BoneCPExample.main(BoneCPExample.java:28) Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Level at java.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) ... 7 more Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Level at org.slf4j.LoggerFactory.bind(LoggerFactory.java:128) at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108) at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:279) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:252) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:265) at com.jolbox.bonecp.BoneCPConfig.<clinit>(BoneCPConfig.java:60) at javasampleapps.BoneCPExample.main(BoneCPExample.java:28) Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Level at java.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) ... 7 more Java Result: 1 BUILD SUCCESSFUL (total time: 0 seconds)

该如何解决?

推荐答案

如果包含slf4j-log4j12-1.6.4.jar，则还必须包含log4j jar. Slf4j是一个日志记录外观，这意味着它为您提供了到多个其他日志记录API的统一接口.

If you include slf4j-log4j12-1.6.4.jar, then you must also include the log4j jar. Slf4j is a logging facade, which means it gives you a uniform interface to multiple other logging APIs.

slf4j-log4j12提供了到log4j API的转换.由于您不包括log4j库，因此会引发错误.不包括slf4j-log4j12库就足够了(如果仅包括slf4j-api库，则应将其默认为无操作记录器AFAIK).

The slf4j-log4j12 provides a conversion to the log4j API. As you don't include the log4j library, it throws an error. Not including the slf4j-log4j12 library should be enough (if only the slf4j-api library is included, then it should then default to a no-operation logger AFAIK).