我正在将slf4j与log4j 2.0或logback一起使用。例如，我的servlet有一个ERROR级别的记录器，我的服务器产生了servlet的100个线程。我将在运行时获得特殊用户的列表。当我检测到某些特殊用户连接时。我想将那些特殊用户/线程的日志级别更改为DEBUG，并保持其他线程的日志级别不受影响(仍然为ERROR)。
我知道logback中的TurboFilter和log4j 2.0中的DynamicThresholdFilter，但是由于我只会在运行时获得特殊用户列表，因此无法使用它们。
这是我的应用程序:
package com.example.logging;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServlet;
import org.slf4j.*;
public class App extends HttpServlet {
private final Logger Logger = LoggerFactory.getLogger(App.class);
Map<String, String> map = new HashMap<String, String>();
public App() {
map.put("user1", "DEBUG");
map.put("user2", "DEBUG");
map.put("user3", "ERROR");
}
public void writeToLogFile(String userName) {
if (map.containsKey(userName)) {
// do something so that I can change the logger to the corresponding log level
}
Logger.error(userName + " error message");
// the logger is of level ERROR, so by default, this log event will not happen
// but I want it to happen for special users
if (Logger.isDebugEnabled()) {
Logger.debug(userName + " debug message");
}
}
}
这是我在log4j2.xml中的日志配置
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="ERROR">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%-5level %class{36} %M %msg%xEx%n" />
</Console>
</Appenders>
<Loggers>
<Logger name="com.example.logging.App" level="ERROR" additivity="false">
<AppenderRef ref="Console" />
</Logger>
<Root level="DEBUG">
<AppenderRef ref="Console" />
</Root>
</Loggers>
</Configuration>
如果我调用以下方法:
App myApp = new App();
// assume the below 4 methods are called concurrently
myApp.writeToLogFile("user1");
myApp.writeToLogFile("user2");
myApp.writeToLogFile("user3");
myApp.writeToLogFile("user4");
预期输出应为:
ERROR com.example.logging.App writeToLogFile - user1 error message
DEBUG com.example.logging.App writeToLogFile - user1 debug message
ERROR com.example.logging.App writeToLogFile - user2 error message
DEBUG com.example.logging.App writeToLogFile - user2 debug message
ERROR com.example.logging.App writeToLogFile - user3 error message
ERROR com.example.logging.App writeToLogFile - user4 error message
最佳答案
我遇到了同样的问题，最终我对DynamicThresholdFilter进行了更改，从而使用了自己的过滤器
对应用程序的更改:
package com.example.logging;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServlet;
import org.slf4j.*;
public class App extends HttpServlet {
private final Logger Logger = LoggerFactory.getLogger(App.class);
Map<String, String> map = new HashMap<String, String>();
public App() {
map.put("user1", "Debug");
map.put("user2", "Debug");
map.put("user3", "Error");
}
public void writeToLogFile(String userName) {
// if the user is in the map, we put it into ThreadConext for filtering
if (map.containsKey(userName)) {
MDC.put("level", map.get(userName));
}
Logger.error(userName + " error message");
if (Logger.isDebugEnabled()) {
Logger.debug(userName + " debug message");
}
// remember to remove it
MDC.remove("level");
}
}
这是基于DynamicThresholdFilter的新定义的过滤器，我们将其称为DynamicThresholdUserFilter，您可以将其与the source code of DynamicThresholdFilter进行比较
package com.example.logging.log4j2.plugin;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.ThreadContext;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.Logger;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.filter.AbstractFilter;
import org.apache.logging.log4j.message.Message;
/**
* Compare against a log level that is associated with an MDC value.
*/
@Plugin(name = "DynamicThresholdUserFilter", category = "Core", elementType = "filter", printObject = true)
public final class DynamicThresholdUserFilter extends AbstractFilter {
private Level defaultThreshold = Level.ERROR;
private final String key;
private DynamicThresholdUserFilter(final String key, final Level defaultLevel,
final Result onMatch, final Result onMismatch) {
super(onMatch, onMismatch);
if (key == null) {
throw new NullPointerException("key cannot be null");
}
this.key = key;
this.defaultThreshold = defaultLevel;
}
public String getKey() {
return this.key;
}
@Override
public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
final Object... params) {
return filter(level);
}
@Override
public Result filter(final Logger logger, final Level level, final Marker marker, final Object msg,
final Throwable t) {
return filter(level);
}
@Override
public Result filter(final Logger logger, final Level level, final Marker marker, final Message msg,
final Throwable t) {
return filter(level);
}
@Override
public Result filter(final LogEvent event) {
return filter(event.getLevel());
}
/* biggest change here */
private Result filter(final Level level) {
final String value = ThreadContext.get(key);
if (value != null) {
Level ctxLevel = Level.toLevel(value);
if (ctxLevel == null) {
// in case the level is invalid
ctxLevel = defaultThreshold;
}
return level.isAtLeastAsSpecificAs(ctxLevel) ? onMatch : onMismatch;
}
return Result.NEUTRAL;
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
sb.append("key=").append(key);
sb.append(", default=").append(defaultThreshold);
return sb.toString();
}
/**
* Create the DynamicThresholdFilter.
* @param key The name of the key to compare.
* @param pairs An array of value and Level pairs.
* @param levelName The default Level.
* @param match The action to perform if a match occurs.
* @param mismatch The action to perform if no match occurs.
* @return The DynamicThresholdFilter.
*/
@PluginFactory
public static DynamicThresholdUserFilter createFilter(
@PluginAttribute("key") final String key,
@PluginAttribute("defaultThreshold") final String levelName,
@PluginAttribute("onMatch") final String match,
@PluginAttribute("onMismatch") final String mismatch) {
final Result onMatch = Result.toResult(match);
final Result onMismatch = Result.toResult(mismatch);
final Level level = Level.toLevel(levelName, Level.ERROR);
return new DynamicThresholdUserFilter(key, level, onMatch, onMismatch);
}
}
将DynamicThresholdUserFilter和程序包名称添加到您的配置文件中
<?xml version="1.0" encoding="UTF-8"?>
<!-- add the package name of the filter-->
<Configuration status="ERROR" packages="com.example.logging.plugin">
<!-- configuration of the new defined filter -->
<DynamicThresholdUserFilter key="level" defaultThreshold="ERROR" onMatch="ACCEPT" onMismatch="NEUTRAL" />
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%-5level %class{36} %M %msg%xEx%n"/>
</Console>
</Appenders>
<Loggers>
<Logger name="com.example.logging.App" level="ERROR" additivity="false">
<AppenderRef ref="Console" />
</Logger>
<Root level="debug">
<AppenderRef ref="Console" />
</Root>
</Loggers>
</Configuration>
新定义的过滤器与DynamicThresholdFilter非常相似。区别在于DynamicThresholdFilter使用配置文件中的预定义级别作为动态阈值，而此过滤器使用映射中以编程方式定义的级别。