Android 如何使用log4j及注意事项

 android 使用log4j

前言：

 如果要直接在android工程中使用log4j，是有点问题的，会报如下的错：

11-23 09:44:56.947: d/dalvikvm(1585): gc_for_malloc freed 3278 objects / 311568 bytes in 31ms 
rejecting opcode 0x21 at 0x000a 
rejected lorg/apache/log4j/config/propertysetter;.getpropertydescriptor 
(ljava/lang/string;)ljava/beans/propertydescriptor; 
verifier rejected class lorg/apache/log4j/config/propertysetter; 
exception ljava/lang/verifyerror; thrown during lorg/apache/log4j/logmanager;. 
shutting down vm 
threadid=1: thread exiting with uncaught exception (group=0x400259f8) 
fatal exception: main 
java.lang.exceptionininitializererror 
at org.slf4j.impl.log4jloggerfactory.getlogger(log4jloggerfactory.java:64) 
at org.slf4j.loggerfactory.getlogger(loggerfactory.java:253) 
at org.slf4j.loggerfactory.getlogger(loggerfactory.java:265) 
... 
caused by: java.lang.verifyerror: org.apache.log4j.config.propertysetter 
at org.apache.log4j.propertyconfigurator.parseappender(propertyconfigurator.java:772) 
at org.apache.log4j.propertyconfigurator.parsecategory(propertyconfigurator.java:735) 
at org.apache.log4j.propertyconfigurator.configurerootcategory(propertyconfigurator.java:615) 
at org.apache.log4j.propertyconfigurator.doconfigure(propertyconfigurator.java:502) 
at org.apache.log4j.propertyconfigurator.doconfigure(propertyconfigurator.java:547) 
at org.apache.log4j.helpers.optionconverter.selectandconfigure(optionconverter.java:483) 
at org.apache.log4j.logmanager.(logmanager.java:127) 
... 20 more 

因此，可以另外多下载一个叫android-logging-log4j的项目，地址在：

http://code.google.com/p/android-logging-log4j/downloads/list，注意，原本的log4j还是需要的。

  在androidmanifest.xml中，增加如下设置：

<uses-permission android:name="android.permission.write_external_storage" /> 

   然后在程序中如下使用：  

package com.android.myapp; 
  
. 
import java.io.file; 
  
 
import org.apache.log4j.level; 
  
 
import org.apache.log4j.logger; 
. 
import android.app.application; 
  
 
import android.os.environment; 
  
 
import de.mindpipe.android.logging.log4j.logconfigurator; 
 . 
  
public class myapplication extends application { 
  
 
    @override 
  
 
    public void oncreate() { 
  
 
        super.oncreate(); 
  
 
        logconfigurator logconfigurator = new logconfigurator(); 
  
 
        logconfigurator.setfilename(environment.getexternalstoragedirectory() 
  
 
                + file.separator + "myapp" + file.separator + "logs" 
  
 
                + file.separator + "log4j.txt"); 
  
 
        logconfigurator.setrootlevel(level.debug); 
  
 
        logconfigurator.setlevel("org.apache", level.error); 
  
 
        logconfigurator.setfilepattern("%d %-5p [%c{2}]-[%l] %m%n"); 
  
 
        logconfigurator.setmaxfilesize(1024 * 1024 * 5); 
  
 
        logconfigurator.setimmediateflush(true); 
  
 
        logconfigurator.configure(); 
  
 
        logger log = logger.getlogger(myapplication.class); 
  
 
        log.info("my application created"); 
  
 
    } 
  
 
} 

     现在日志则是以：

environment.getexternalstoragedirectory() + file.separator + "myapp" + file.separator + "logs" + file.separator + "log4j.txt
   的方式保存了。其他和log4j的用法差不多了。

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