Logback的核心API调用，动态输出日志

前言

项目碰到了不能读logback配置文件，因为配置文件是第一次启动读的，然后我程序运行时要动态写。

比如这种场景：根据不同的业务id，生成不同的日志文件。

因为动态场景，无法写配置文件，我们只能通过调用自己输出，然后自己输出还得写文件，为什么不借助logback的api去写文件呢？毕竟别人开源的代码比我们牛逼！

写代码之前，从官网看一下logback工作原理（为了让你们感觉我是看懂了原理图，手撸出来的代码），然后当然是看不懂的！233。

还是看我的代码实现吧！

实现

新建一个类LoggerBuilder.class

package com.hyperdai.DcServer.utils;

import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
import ch.qos.logback.core.ConsoleAppender;
import ch.qos.logback.core.rolling.RollingFileAppender;
import ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy;
import ch.qos.logback.core.util.FileSize;
import ch.qos.logback.core.util.OptionHelper;
import org.slf4j.LoggerFactory;

import java.text.DateFormat;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

/**
 * author hyperdai
 * create 2019-04-08 17:10
 */
public class LoggerBuilder {

    private static final Map<String,Logger> container = new HashMap<>();
    private static final String LOG_PATH = "/Users/hyperdai/Projects/java_dcserver/water/midas";

    public Logger getLogger(String name) {
        Logger logger = container.get(name);
        if(logger != null) {
            return logger;
        }
        synchronized (LoggerBuilder.class) {
            logger = container.get(name);
            if(logger != null) {
                return logger;
            }
            logger = build(name);
            container.put(name,logger);
        }
        return logger;
    }




    private static Logger build(String name) {
        DateFormat format = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.SIMPLIFIED_CHINESE);
        LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();


        Logger logger = context.getLogger("FILE-" + name);
        logger.setAdditive(false);
        RollingFileAppender appender = new RollingFileAppender();

        appender.setContext(context);
//        appender.setFile(LoggerBuilder.LOG_PATH  + "/[" + name + "]midas.%d.%i.log");
        appender.setName("FILE-" + name);
        SizeAndTimeBasedRollingPolicy policy = new SizeAndTimeBasedRollingPolicy();

        String fp = OptionHelper.substVars(LoggerBuilder.LOG_PATH  + "/"+name+"/%d{yyyy-MM-dd}.%i.log", context);
        policy.setFileNamePattern(fp);
        policy.setMaxFileSize(FileSize.valueOf("128MB"));
        policy.setMaxHistory(15);
        policy.setTotalSizeCap(FileSize.valueOf("32GB"));
        policy.setParent(appender);
        policy.setContext(context);
        policy.start();

        PatternLayoutEncoder encoder = new PatternLayoutEncoder();
        encoder.setContext(context);
        encoder.setPattern("%d %p (%file:%line\\)- %msg%n");
        encoder.start();

        appender.setRollingPolicy(policy);
        appender.setEncoder(encoder);
        appender.start();
        logger.addAppender(appender);

        /*设置动态日志控制台输出*/
        PatternLayoutEncoder encoder1 = new PatternLayoutEncoder();
        encoder1.setContext(context);
        encoder1.setPattern("%d %p (%file:%line\\)- %msg%n");
        encoder1.start();

        ConsoleAppender consoleAppender = new ConsoleAppender();
        consoleAppender.setContext(context);
        consoleAppender.setEncoder(encoder1);
        consoleAppender.start();
        logger.addAppender(consoleAppender);


        return logger;
    }

    public static void main(String[] args) {
        System.out.println("hhhhh");
    }
}

简单调用测试

LoggerBuilder loggerBuilder =new LoggerBuilder();
Logger logger = loggerBuilder.getLogger("1");
logger.info("123456");

控制台ok啊：
2019-05-09 00:58:46,482 INFO (DcServer.java:52)- 123456
我也感觉ok！

参考

https://blog.csdn.net/weixin_42258128/article/details/81942796
https://blog.csdn.net/jasonlibint/article/details/81942790
https://segmentfault.com/a/1190000008315137#articleHeader9