问题
So,
I'm working from this example 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();
}
}
}
}
}
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.
Then I made a Google Guava library and added the jar that they distribute for that to another library.
I then added both of the libraries to the project and hit run.
I now get this error:
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.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$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.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$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)
What can I do to fix this?
回答1:
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.
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).
来源:https://stackoverflow.com/questions/8388078/failed-to-instantiate-slf4j-loggerfactory