Java 9模块化应用程序中的Logback不工作

我有一个使用Java9的Maven项目，正在使用模块。从版本1.3.0-alpha1开始，Logback似乎就支持这一点，但不幸的是，我没有让它工作

我从SLF4J收到以下消息：

SLF4J: No SLF4J providers were found.
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#noProviders for further details.

看起来好像找不到Logback。使用

jimage list…/modules

检查（由Jlink生成的）工件，除了logback.xml配置文件之外，我找不到任何关于logback的信息

可能问题出在我的module-info.java中：

open module my.super.app {
    requires jackson.annotations;
    requires jdk.jsobject;
    requires com.fasterxml.jackson.databind;
    requires com.fasterxml.jackson.core;
    requires javafx.graphics;
    requires javafx.controls;
    requires org.slf4j;

    exports my.super.app;
}

open module my.super.app {
    requires jackson.annotations;
    requires jdk.jsobject;
    requires com.fasterxml.jackson.databind;
    requires com.fasterxml.jackson.core;
    requires javafx.graphics;
    requires javafx.controls;
    requires org.slf4j;
    requires ch.qos.logback.classic; //only runtime dependency

    exports my.super.app;
}

---

如何以及在何处声明依赖于使用Java 9模块的Logback？

我终于找到了答案。最后，我在module-info.java中添加了Logback作为依赖项：

open module my.super.app {
    requires jackson.annotations;
    requires jdk.jsobject;
    requires com.fasterxml.jackson.databind;
    requires com.fasterxml.jackson.core;
    requires javafx.graphics;
    requires javafx.controls;
    requires org.slf4j;

    exports my.super.app;
}

open module my.super.app {
    requires jackson.annotations;
    requires jdk.jsobject;
    requires com.fasterxml.jackson.databind;
    requires com.fasterxml.jackson.core;
    requires javafx.graphics;
    requires javafx.controls;
    requires org.slf4j;
    requires ch.qos.logback.classic; //only runtime dependency

    exports my.super.app;
}

---

我想没有办法声明一个运行时依赖项（类似于Maven）——它现在在编译时也是必需的。

简短回答：您可以通过向模块路径添加logback并使用--bind services选项在jlink调用中声明它。在您的模块中，您仅定义SLF4j的用法

长答案：

我通过以下几个部分在一个简单的示例中实现了它

从版本1.8.0开始，并使用该机制查找其日志后端

Logback classic:1.3.0-alpha4也是模块化的，并且在META-INF/services/org.slf4j.spi.SLF4JServiceProvider及其模块描述符中声明了一个服务：

provides org.slf4j.spi.SLF4JServiceProvider with ch.qos.logback.classic.spi.LogbackServiceProvider;

SLF4J在其模块描述符中声明它需要一个SLF4JServiceProvider：

uses org.slf4j.spi.SLF4JServiceProvider

因此，在我的POM（见下文）中，我只向Logback声明一个运行时依赖项，我的模块描述符只包含一个SLF4J的“requires”子句

我的模块“com.github.gv2011.j9mod.loguse”包含一个将语句记录到SLF4J记录器的主类

此外，它还包含一个logback.xml配置文件作为资源。此文件可供Logback访问，因为它是一个“杂项资源”，这是一个不在模块包中的资源（请参阅源代码）

必须通过jlink“-bind services”选项将Logback明确地添加到运行时映像中（因为它是一个服务实现）

此外，Logback及其依赖项必须在modulepath（jlink“--modulepath”选项）上可用

模块描述符：

module com.github.gv2011.j9mod.loguse {
  requires org.slf4j;
}

<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.github.gv2011.j9mod</groupId>
  <artifactId>j9mod-log-use</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
  <dependencies>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.8.0-beta4</version>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.3.0-alpha4</version>
        <scope>runtime</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <release>11</release>
            </configuration>
        </plugin>
    </plugins>
</build>

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <!-- "+++" just to make it obvious that this file is used: -->
      <pattern>+++ %d{"yyyy-MM-dd'T'HH:mm:ss,SSSXXX", UTC} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
  </appender>

  <logger name="com.github.gv2011.j9mod.loguse.Main" level="INFO" />

  <root level="WARN">
    <appender-ref ref="STDOUT" />
  </root>

</configuration>

package com.github.gv2011.j9mod.loguse;
import static org.slf4j.LoggerFactory.getLogger;
import org.slf4j.Logger;

public class Main {

  private static final Logger LOG = getLogger(Main.class);

  public static void main(final String[] args) {
    LOG.info("Tach.");
  }
}

+++ 2019-05-09T17:43:20,594Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

%JAVA_HOME%\bin\jlink.exe ^
--output target\image ^
--module-path ^
target\classes;^
%M2_REPO%\org\slf4j\slf4j-api\1.8.0-beta4\slf4j-api-1.8.0-beta4.jar;^
%M2_REPO%\ch\qos\logback\logback-classic\1.3.0-alpha4\logback-classic-1.3.0-alpha4.jar;^
%M2_REPO%\ch\qos\logback\logback-core\1.3.0-alpha4\logback-core-1.3.0-alpha4.jar ^
--bind-services ^
--launcher hello=com.github.gv2011.j9mod.loguse/com.github.gv2011.j9mod.loguse.Main ^
--add-modules com.github.gv2011.j9mod.loguse

+++ 2019-05-10T11:45:24,844Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

pom.xml：

module com.github.gv2011.j9mod.loguse {
  requires org.slf4j;
}

<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.github.gv2011.j9mod</groupId>
  <artifactId>j9mod-log-use</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
  <dependencies>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.8.0-beta4</version>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.3.0-alpha4</version>
        <scope>runtime</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <release>11</release>
            </configuration>
        </plugin>
    </plugins>
</build>

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <!-- "+++" just to make it obvious that this file is used: -->
      <pattern>+++ %d{"yyyy-MM-dd'T'HH:mm:ss,SSSXXX", UTC} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
  </appender>

  <logger name="com.github.gv2011.j9mod.loguse.Main" level="INFO" />

  <root level="WARN">
    <appender-ref ref="STDOUT" />
  </root>

</configuration>

package com.github.gv2011.j9mod.loguse;
import static org.slf4j.LoggerFactory.getLogger;
import org.slf4j.Logger;

public class Main {

  private static final Logger LOG = getLogger(Main.class);

  public static void main(final String[] args) {
    LOG.info("Tach.");
  }
}

+++ 2019-05-09T17:43:20,594Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

%JAVA_HOME%\bin\jlink.exe ^
--output target\image ^
--module-path ^
target\classes;^
%M2_REPO%\org\slf4j\slf4j-api\1.8.0-beta4\slf4j-api-1.8.0-beta4.jar;^
%M2_REPO%\ch\qos\logback\logback-classic\1.3.0-alpha4\logback-classic-1.3.0-alpha4.jar;^
%M2_REPO%\ch\qos\logback\logback-core\1.3.0-alpha4\logback-core-1.3.0-alpha4.jar ^
--bind-services ^
--launcher hello=com.github.gv2011.j9mod.loguse/com.github.gv2011.j9mod.loguse.Main ^
--add-modules com.github.gv2011.j9mod.loguse

+++ 2019-05-10T11:45:24,844Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

输出（Eclipse-runas-Java应用程序）：

module com.github.gv2011.j9mod.loguse {
  requires org.slf4j;
}

<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.github.gv2011.j9mod</groupId>
  <artifactId>j9mod-log-use</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
  <dependencies>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.8.0-beta4</version>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.3.0-alpha4</version>
        <scope>runtime</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <release>11</release>
            </configuration>
        </plugin>
    </plugins>
</build>

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <!-- "+++" just to make it obvious that this file is used: -->
      <pattern>+++ %d{"yyyy-MM-dd'T'HH:mm:ss,SSSXXX", UTC} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
  </appender>

  <logger name="com.github.gv2011.j9mod.loguse.Main" level="INFO" />

  <root level="WARN">
    <appender-ref ref="STDOUT" />
  </root>

</configuration>

package com.github.gv2011.j9mod.loguse;
import static org.slf4j.LoggerFactory.getLogger;
import org.slf4j.Logger;

public class Main {

  private static final Logger LOG = getLogger(Main.class);

  public static void main(final String[] args) {
    LOG.info("Tach.");
  }
}

+++ 2019-05-09T17:43:20,594Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

%JAVA_HOME%\bin\jlink.exe ^
--output target\image ^
--module-path ^
target\classes;^
%M2_REPO%\org\slf4j\slf4j-api\1.8.0-beta4\slf4j-api-1.8.0-beta4.jar;^
%M2_REPO%\ch\qos\logback\logback-classic\1.3.0-alpha4\logback-classic-1.3.0-alpha4.jar;^
%M2_REPO%\ch\qos\logback\logback-core\1.3.0-alpha4\logback-core-1.3.0-alpha4.jar ^
--bind-services ^
--launcher hello=com.github.gv2011.j9mod.loguse/com.github.gv2011.j9mod.loguse.Main ^
--add-modules com.github.gv2011.j9mod.loguse

+++ 2019-05-10T11:45:24,844Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

jlink：

module com.github.gv2011.j9mod.loguse {
  requires org.slf4j;
}

<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.github.gv2011.j9mod</groupId>
  <artifactId>j9mod-log-use</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
  <dependencies>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.8.0-beta4</version>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.3.0-alpha4</version>
        <scope>runtime</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <release>11</release>
            </configuration>
        </plugin>
    </plugins>
</build>

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <!-- "+++" just to make it obvious that this file is used: -->
      <pattern>+++ %d{"yyyy-MM-dd'T'HH:mm:ss,SSSXXX", UTC} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
  </appender>

  <logger name="com.github.gv2011.j9mod.loguse.Main" level="INFO" />

  <root level="WARN">
    <appender-ref ref="STDOUT" />
  </root>

</configuration>

package com.github.gv2011.j9mod.loguse;
import static org.slf4j.LoggerFactory.getLogger;
import org.slf4j.Logger;

public class Main {

  private static final Logger LOG = getLogger(Main.class);

  public static void main(final String[] args) {
    LOG.info("Tach.");
  }
}

+++ 2019-05-09T17:43:20,594Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

%JAVA_HOME%\bin\jlink.exe ^
--output target\image ^
--module-path ^
target\classes;^
%M2_REPO%\org\slf4j\slf4j-api\1.8.0-beta4\slf4j-api-1.8.0-beta4.jar;^
%M2_REPO%\ch\qos\logback\logback-classic\1.3.0-alpha4\logback-classic-1.3.0-alpha4.jar;^
%M2_REPO%\ch\qos\logback\logback-core\1.3.0-alpha4\logback-core-1.3.0-alpha4.jar ^
--bind-services ^
--launcher hello=com.github.gv2011.j9mod.loguse/com.github.gv2011.j9mod.loguse.Main ^
--add-modules com.github.gv2011.j9mod.loguse

+++ 2019-05-10T11:45:24,844Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

输出（target/image/bin/hello）：

module com.github.gv2011.j9mod.loguse {
  requires org.slf4j;
}

<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.github.gv2011.j9mod</groupId>
  <artifactId>j9mod-log-use</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
  <dependencies>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.8.0-beta4</version>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.3.0-alpha4</version>
        <scope>runtime</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <release>11</release>
            </configuration>
        </plugin>
    </plugins>
</build>

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <!-- "+++" just to make it obvious that this file is used: -->
      <pattern>+++ %d{"yyyy-MM-dd'T'HH:mm:ss,SSSXXX", UTC} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
  </appender>

  <logger name="com.github.gv2011.j9mod.loguse.Main" level="INFO" />

  <root level="WARN">
    <appender-ref ref="STDOUT" />
  </root>

</configuration>

package com.github.gv2011.j9mod.loguse;
import static org.slf4j.LoggerFactory.getLogger;
import org.slf4j.Logger;

public class Main {

  private static final Logger LOG = getLogger(Main.class);

  public static void main(final String[] args) {
    LOG.info("Tach.");
  }
}

+++ 2019-05-09T17:43:20,594Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

%JAVA_HOME%\bin\jlink.exe ^
--output target\image ^
--module-path ^
target\classes;^
%M2_REPO%\org\slf4j\slf4j-api\1.8.0-beta4\slf4j-api-1.8.0-beta4.jar;^
%M2_REPO%\ch\qos\logback\logback-classic\1.3.0-alpha4\logback-classic-1.3.0-alpha4.jar;^
%M2_REPO%\ch\qos\logback\logback-core\1.3.0-alpha4\logback-core-1.3.0-alpha4.jar ^
--bind-services ^
--launcher hello=com.github.gv2011.j9mod.loguse/com.github.gv2011.j9mod.loguse.Main ^
--add-modules com.github.gv2011.j9mod.loguse

+++ 2019-05-10T11:45:24,844Z [main] INFO  com.github.gv2011.j9mod.loguse.Main - Tach.

---

使用openjdk-11.0.2_windows-x64、apache-maven-3.6.0和eclipse-jee-2019-03-R-win32-x86_64在windows 10上进行测试，64位。

这不是警告，不是错误吗？-是的，这只是一个警告。但它表示它无法记录/查找Logback。我的日志文件也没有被写入。嗯，你把Logback添加到modulepath了吗？是的，但我想它被Jlink删除了。我也有类似的问题。您使用的是哪个版本的SLF4J？1.8.x或更早版本？在Maven中，我导入ch.qos.logback/logback-classic/1.3.0-alpha4，它本身导入org.slf4j/slf4j-api/1.8.0-beta1。