嵌入式Tomcat通过logback/sl4j进行日志记录

Question

如何让嵌入式tomcat通过logback写入日志？我找到了一些关于使用log4j的独立tomcat的信息.但是嵌入式tomcat和logback的设置如何？

这些是maven依赖项:

<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-core</artifactId>
    <version>${logback.version}</version>
</dependency>
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
    <version>${tomcat.version}</version>
</dependency>
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-logging-juli</artifactId>
    <version>${tomcat.version}</version>
</dependency>
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-logging-log4j</artifactId>
    <version>${tomcat.version}</version>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>log4j-over-slf4j</artifactId>
    <version>${sl4j.version}</version>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>jul-to-slf4j</artifactId>
    <version>${sl4j.version}</version>
</dependency>

我知道Spring Boot会自动执行tomcat日志记录集成.但在这种情况下我不能使用Spring.

Answer 1

Tomcat 8 有一个ServiceLoader基于发现的机制，可让您部署自己的记录器实现。

org.apache.juli.logging.Log只需在委托给 Logback/SLF4J 的类中实现，并将类名放入META-INF/services/org.apache.juli.logging.Log类路径上的文件中即可。然后 Tomcat 将通过您的类进行登录。

import org.apache.juli.logging.Log;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class DelegateToSlf4jLogger implements Log {
    private final Logger logger;

    // constructor required by ServiceLoader
    public DelegateToSlf4jLogger() {
        logger = null;
    }

    public DelegateToSlf4jLogger(String name){
        logger = LoggerFactory.getLogger(name);
    }

    @Override
    public boolean isDebugEnabled() {
        return logger.isDebugEnabled();
    }

    @Override
    public boolean isErrorEnabled() {
        return logger.isErrorEnabled();
    }

    @Override
    public boolean isFatalEnabled() {
        return logger.isErrorEnabled();
    }

    @Override
    public boolean isInfoEnabled() {
        return logger.isInfoEnabled();
    }

    @Override
    public boolean isTraceEnabled() {
        return logger.isTraceEnabled();
    }

    @Override
    public boolean isWarnEnabled() {
        return logger.isWarnEnabled();
    }

    @Override
    public void trace(Object message) {
        logger.debug(String.valueOf(message));
    }

    @Override
    public void trace(Object message, Throwable t) {
        logger.debug(String.valueOf(message), t);
    }

    @Override
    public void debug(Object message) {
        logger.debug(String.valueOf(message));
    }

    @Override
    public void debug(Object message, Throwable t) {
        logger.debug(String.valueOf(message), t);
    }

    @Override
    public void info(Object message) {
        logger.info(String.valueOf(message));
    }

    @Override
    public void info(Object message, Throwable t) {
        logger.info(String.valueOf(message), t);
    }

    @Override
    public void warn(Object message) {
        logger.warn(String.valueOf(message));
    }

    @Override
    public void warn(Object message, Throwable t) {
        logger.warn(String.valueOf(message), t);
    }

    @Override
    public void error(Object message) {
        logger.error(String.valueOf(message));
    }

    @Override
    public void error(Object message, Throwable t) {
        logger.error(String.valueOf(message), t);
    }

    @Override
    public void fatal(Object message) {
        logger.error(String.valueOf(message));
    }

    @Override
    public void fatal(Object message, Throwable t) {
        logger.error(String.valueOf(message), t);
    }
}