捕获log4j输出 [英] Capture log4j output
问题描述
我们正在系统中广泛使用log4j2
,并使用log4j2.xml
对其进行配置.
We are using log4j2
extensively in our system, and configures it with log4j2.xml
.
现在,我需要一个运行jobs
的新应用,并且我想分别捕获时间X和Y之间生成的所有日志,并将其放入数据库中.从我们的框架进行的正常日志记录应该照常发生(到文件或log4j2.xml指向的任何地方),但是从时间X到时间Y.
Now I need a new app that run jobs
, and I want to separately capture all the logs resulted between time X and Y and put it in a database. Normal logging from our framework should occur as usual (to files or wherever log4j2.xml points to), But from time X to time Y.
我还希望捕获所有日志记录,最好是捕获到字符串列表或可以保存在数据库表中的内容.
I also want all the logging should be captured, preferably to a list of strings or something that can be saved in a database table.
我的想法是创建一个新的Appender(捕获所有日志输出)并动态添加/删除该附加程序以启动和停止日志?那行得通吗?我也可以在框架类中重新配置记录器吗?
My idea is to create a new Appender (that captures all logging output) and dynamically add/remove that appender to start and stop logging? Would that work? Can I reconfigure the loggers in the framework classes too?
推荐答案
有可能.您需要创建一个自定义附加程序.例如:
It is possible. You need to create a custom appender. e.g.:
public class CustomAppender extends AbstractAppender {
private List<String> list = new ArrayList<>();
public CustomAppender(String name, Filter filter, Layout<? extends Serializable> layout) {
super(name, filter, layout);
}
public CustomAppender(String name, Filter filter, Layout<? extends Serializable> layout, boolean ignoreExceptions) {
super(name, filter, layout, ignoreExceptions);
}
@Override
public void append(LogEvent event) {
byte[] data = getLayout().toByteArray(event);
list.add(new String(data).trim()); // optional trim
}
@Override
public void stop() {
// Write to the database
System.out.println(list);
}
}
每个事件都转换为一个字符串,该字符串将添加到列表中. stop
方法是在删除附加程序后自动执行的.
Each event is converted to a string, which is added to the list. The stop
method is automatically executed after removing the appender.
以下代码示例了此附加器的使用.
The following code exemplifies the use of this appender.
public static void main(String[] args) {
// Execute some jobs
for (int n = 0; n < 10; n++) {
dummyJob(n);
}
}
private static void dummyJob(int n) {
final LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
final AbstractConfiguration config = (AbstractConfiguration) ctx.getConfiguration();
// Create and add the appender
CustomAppender appender = new CustomAppender("Custom", null, PatternLayout.createDefaultLayout());
appender.start();
config.addAppender(appender);
// Create and add the logger
AppenderRef[] refs = new AppenderRef[]{AppenderRef.createAppenderRef("Custom", null, null)};
LoggerConfig loggerConfig = LoggerConfig.createLogger("false", Level.INFO, "com.company", "true", refs, null, config, null);
loggerConfig.addAppender(appender, null, null);
config.addLogger("com.company", loggerConfig);
ctx.updateLoggers();
// Run the job
Logger logger = LogManager.getLogger("com.company");
logger.info("Job {}", n);
logger.info("Hello, World!");
logger.info("This is awesome!");
logger.info("Hope it works!");
logger.info("Hope it helps!");
// Remove the logger and appender
config.removeLogger("com.company");
config.removeAppender("Custom");
ctx.updateLoggers();
}
后者的输出:
[Job 0, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 1, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 2, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 3, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 4, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 5, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 6, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 7, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 8, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
[Job 9, Hello, World!, This is awesome!, Hope it works!, Hope it helps!]
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