[英]Log4j2 on Android
我正在嘗試在Android Project上使用log4j2(我正在使用Android Studio)。
為了簡化這個問題,我將解釋我在一個簡單的虛擬項目中所做的事情(我在實際項目中得到的錯誤與這個虛擬項目相同)。
我創建了一個帶有主要活動的簡單虛擬項目。
我添加了log4j2庫...
這是gradle:
apply plugin: 'com.android.application'
android {
packagingOptions {
exclude 'META-INF/LICENSE'
exclude 'META-INF/NOTICE'
}
compileSdkVersion 21
buildToolsVersion "21.1.2"
defaultConfig {
applicationId "com.example.test20150130"
minSdkVersion 19
targetSdkVersion 21
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:21.0.3'
compile 'com.android.support:support-v4:21.0.3'
compile group: 'org.apache.logging.log4j', name: 'log4j-api', version: '2.1'
compile group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.1'
}
我已將log4j2.xml縮減為:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="debug">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<ThresholdFilter level="ALL" onMatch="ACCEPT" onMismatch="DENY"/>
<PatternLayout pattern="%m%n" />
</Console>
</Appenders>
<Loggers>
<root level="INFO">
<AppenderRef ref="Console"/>
</root>
<logger name="Queries" level="ALL" additivity="false">
<AppenderRef ref="Console"/>
</logger>
</Loggers>
在Activity上,我導入了庫...
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
但是當我嘗試使用它們時......
Logger logger= LogManager.getLogger ("Queries");
logger.error ("It works...");
我在'Logger logger = LogManager.getLogger(“Queries”)上有錯誤;'
01-30 00:49:29.413 1685-1685/com.example.test20150130 E/AndroidRuntime? FATAL EXCEPTION: main
Process: com.example.test20150130, PID: 1685
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.test20150130/com.example.test20150130.MainScreenActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at org.apache.logging.log4j.util.ReflectionUtil$PrivateSecurityManager.getCallerClass(ReflectionUtil.java:301)
at org.apache.logging.log4j.util.ReflectionUtil.getCallerClass(ReflectionUtil.java:214)
at org.apache.logging.log4j.util.ReflectionUtil.getCallerClass(ReflectionUtil.java:193)
at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:72)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:195)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:41)
at org.apache.logging.log4j.LogManager.getContext(LogManager.java:160)
at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:492)
at com.example.test20150130.MainScreenActivity.delayedHide(MainScreenActivity.java:162)
at com.example.test20150130.MainScreenActivity.onPostCreate(MainScreenActivity.java:129)
at android.app.Instrumentation.callActivityOnPostCreate(Instrumentation.java:1150)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2178)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
我不確定log4j2.xml文件應該在哪里,所以我把它放在\\ src上,在\\ src \\ main \\ java \\ com \\ example \\ test20150130(與主活動相同的目錄),Test20150130 \\ app \\ build \\ outputs \\ apk(與apk相同的目錄),...
由於錯誤信息,我在各處嘗試了getLogger:最初在onCreate上,然后,我將它托盤在onClick事件上,但是我得到了同樣的錯誤。
(當我托盤調試它時,我看到的來源與實際執行不一致......)
我有log4j已經在Android項目上工作,但我剛剛將一個Java EE項目遷移到log4j2,我想在Android項目上做同樣的事情......
log4j2文檔中關於Android的信息非常少。 它只是說有幾個模塊不能在Android上工作(JNDI,JMX,...),但沒有別的......也許它需要內部的那些模塊(JNDI?)...
尋找信息,我已經建立了這個( https://issues.apache.org/jira/browse/LOG4J2-446?jql=project%20%3D%20LOG4J2%20AND%20text%20 ~%20android )但我做了找到解決方案......
可以在Android上使用log4j2嗎?
非常感謝你提前
我終於得到了我想要的東西......
我正在使用Android,我無法按名稱恢復記錄器(LogManager.getLogger(“xxx”)以最糟糕的方式崩潰應用程序...)
我認為問題在尋找log4j2.xml時開始。 我把文件放在各處,但它不起作用......所以,我想把log4j2.xml內容提供給一個String ...
這就是我所做的......
String log4j2xmlFileContent=getLog4j2xmlContent();//Content of my log4j2.xml
// convert String into InputStream
InputStream is = new ByteArrayInputStream(log4j2xmlFileContent.getBytes());
ConfigurationSource source=null;
try{
source = new ConfigurationSource(is);
} catch (IOException ioe){
ioe.printStackTrace();
}
Configuration config = org.apache.logging.log4j.core.config.xml.XmlConfigurationFactory.getInstance().getConfiguration(source);
loggerContext = (LoggerContext) LogManager.getContext();
try {
//loggerContext.stop();
loggerContext.start(config);
} catch (Exception e){
e.printStackTrace();
}
return loggerContext;
現在,我可以使用loggerContext來獲取我的記錄器......
loggerHitosCarga = context.getLogger("HitosCarga");
loggerPeticiones = context.getLogger("Peticiones");
loggerQueries = context.getLogger("Queries");
loggerDepuracionActual=context.getLogger("DepuracionActual");
loggerDepuracionActual.warn("FUNCIONAAAAA!!!!..");
loggerHitosCarga.info("Loggers inicializados...");
現在我只需要稍微檢討和改進它,但它有效......
基於您自己的答案,但使用簡化的代碼(使用Configurator.initialize()
而不是XmlConfigurationFactory
等):
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.ConfigurationSource;
import org.apache.logging.log4j.core.config.Configurator;
// Content of log4j2.xml
String log4j2xmlFileContent = getLog4j2xmlContent();
// convert String into InputStream
InputStream is = new ByteArrayInputStream(log4j2xmlFileContent.getBytes());
try {
ConfigurationSource source = new ConfigurationSource(is);
return Configurator.initialize(null, source);
} catch (IOException e) {
e.printStackTrace();
}
return null;
注意:
LogManager.getLogger()
Configurator.initialize()
不是log4j2公共API的一部分(參見此處 )
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