java - 如何配置 Gradle 应用程序以将 SLF4J 与 Log4J 2 实现一起使用？

Question

我正在尝试配置一个 Gradle 项目(它使用 Lombok 注释处理器)以将 SLF4J 与 Log4j 2 实现一起使用。该项目 - 使用 gradle init 开始并选择一个 application - 具有以下结构:

.
├── app
│   ├── build
│   │   ├── classes
│   │   │   └── java
│   │   │       └── main
│   │   │           └── log4j
│   │   │               └── App.class
│   │   ├── generated
│   │   │   └── sources
│   │   │       ├── annotationProcessor
│   │   │       │   └── java
│   │   │       │       └── main
│   │   │       └── headers
│   │   │           └── java
│   │   │               └── main
│   │   └── tmp
│   │       └── compileJava
│   │           └── source-classes-mapping.txt
│   ├── build.gradle
│   └── src
│       ├── main
│       │   ├── java
│       │   │   └── log4j
│       │   │       └── App.java
│       │   └── resources
│       └── test
│           ├── java
│           │   └── log4j
│           │       └── AppTest.java
│           └── resources
├── gradle
│   └── wrapper
│       ├── gradle-wrapper.jar
│       └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
├── log4j2.xml
└── settings.gradle

我放了一个 log4j2.xml项目目录下的文件。根据 https://logging.apache.org/log4j/2.x/manual/configuration.html 的自动配置部分中的步骤 9 ,

If a JSON file cannot be located the XML ConfigurationFactory will try to locate log4j2.xml on the classpath.

我的 build.gradle具有所需的依赖项，

/*
 * This file was generated by the Gradle 'init' task.
 *
 * This generated file contains a sample Java application project to get you started.
 * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
 * User Manual available at https://docs.gradle.org/6.8.1/userguide/building_java_projects.html
 */

plugins {
    // Apply the application plugin to add support for building a CLI application in Java.
    id 'application'
}

repositories {
    // Use JCenter for resolving dependencies.
    jcenter()
}

dependencies {
    // Use JUnit test framework.
    testImplementation 'junit:junit:4.13'

    // This dependency is used by the application.
    implementation 'com.google.guava:guava:29.0-jre'

    implementation group: 'org.slf4j', name: 'slf4j-api', version: '2.0.0-alpha1'
    implementation 'org.apache.logging.log4j:log4j-slf4j18-impl:2.14.0'

    compileOnly 'org.projectlombok:lombok:1.18.16'
    annotationProcessor 'org.projectlombok:lombok:1.18.16'

    testCompileOnly 'org.projectlombok:lombok:1.18.16'
    testAnnotationProcessor 'org.projectlombok:lombok:1.18.16'
}

application {
    // Define the main class for the application.
    mainClass = 'log4j.App'
}

和 App类本身是

package log4j;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class App {
    public String getGreeting() {
        return "Hello World!";
    }

    public static void main(String[] args) {
        log.info("Printing a greeting...");
        System.out.println(new App().getGreeting());
    }
}

问题是，如果我使用 ./gradlew run 运行应用程序，它不打印 log.info()线，

> ./gradlew run

> Task :app:run
Hello World!

而如果我将其更改为 log.error() ，它确实被记录:

> ./gradlew run

> Task :app:run
19:26:50.782 [main] ERROR log4j.App - Printing a greeting...
Hello World!

由于我已将级别设置为 trace在 log4j2.xml配置文件，

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
        </Console>
    </Appenders>
    <Loggers>
        <Root level="trace">
            <AppenderRef ref="Console"/>
        </Root>
    </Loggers>
</Configuration>

我建议 info如果配置文件被“拾取”，则显示 -level 日志。这向我表明它不在类路径中。我试过把它复制到 app目录，但无济于事。 log4j2.xml应该在哪里配置文件位于正确配置Log4J 2？

Answer 1

对于 log4j2.xml要在类路径上结束，文件必须移动到 src/main/resources .在官方文档中阅读更多关于资源的信息:

Building Java & JVM projects: Managing resources

The Java Plugin: Project layout