java - 无法使用log4j生成错误文件

Question

我正在运行gradle项目，并且试图将log4j记录到控制台以及文件中。错误记录到控制台时，没有文件被记录。我在src / main / resources中有我的log4j.properties。我尝试将属性文件移动到src文件夹以及SO上建议的几乎每个文件夹都没有成功。我也尝试了log4j中的rollingFile和File。 log4j.properties文件是否有问题，还是我没有将文件放在正确的位置？

这是我当前的文件

log4j.properties

# root level configurations
log4j.rootLogger=INFO,console,rollingFile

# configuration for console outputs
 log4j.appender.console=org.apache.log4j.ConsoleAppender
 log4j.appender.console.layout=org.apache.log4j.PatternLayout

# configuration for file output (into a file named messages.log)
log4j.appender.rollingFile=org.apache.log4j.RollingFileAppender
log4j.appender.rollingFile.File=/home/cbolles/devel/testing/gradle_testing/messages.log
log4j.appender.rollingFile.layout=org.apache.log4j.PatternLayout 

build.gradle

apply plugin: 'java'

repositories {
    jcenter()
}

dependencies {
    compile group: 'org.apache.logging.log4j', name: 'log4j-api', version: '2.8.2'
    compile group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.8.2'
    compile 'org.slf4j:slf4j-log4j12:1.7.18'

    testCompile 'junit:junit:4.12'
}

task(runSimple, dependsOn: 'classes', type: JavaExec) {
    main = 'com.bolles.ErrorTester'
    classpath = sourceSets.main.runtimeClasspath
    args 'mrhaki'
    systemProperty 'simple.message', 'Hello '
}

defaultTasks 'runSimple'

LogTesting.java

package com.bolles;
import java.io.PrintWriter;
import java.io.StringWriter;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class LogTesting
{

    private static final Logger log = LogManager.getLogger(LogTesting.class);

    public static void reportError(Exception e, boolean consoleLog)
    {
        String errorMessage = "";
        if(e.getMessage() != null)
        {
            errorMessage = e.getMessage();
        }

        StringWriter stackTraceWriter = new StringWriter();
        e.printStackTrace( new PrintWriter(stackTraceWriter));
        String stackTrace = stackTraceWriter.toString();

        log.error(errorMessage);
        log.log(Level.ERROR, errorMessage + "\n" + stackTrace);
    }
}

ErrorTester.java

package com.bolles;
public class ErrorTester 
{

    public static void nullStringTest()
    {
        String errorString = null;
        try
        {
            System.out.print(errorString);
        }
        catch(Exception e)
        {
            LogTesting.reportError(e, true);
        }
    }
    public static void main(String[] args)
    {
        nullStringTest();
    }
}

其他答案似乎都不适用于我的问题。

Answer 1

明显的问题似乎是您正在使用log4j的LogManager和Logger类。对LogTesting类进行以下更改(如我所见，slf4j已经在依赖项中)

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
...
private static final Logger log = LoggerFactory.getLogger(LogTesting.class);
...
log.error(errorMessage);
//log.log(Level.ERROR, errorMessage + "\n" + stackTrace); //no such method in slf4j

并且它也应该按预期将错误写入文件中。

(您似乎也需要修改ErrorTester类，因为当前没有从那里抛出异常，因此不调用LogTesting.reportError())