spring boot (4） 使用log4 打印日志

1.排除spring boot  原有的日志依赖

在创建Spring Boot工程时，我们引入了spring-boot-starter，其中包含了spring-boot-starter-logging，该依赖内容就是Spring Boot默认的日志框架Logback，所以我们在引入log4j之前，需要先排除该包的依赖，再引入log4j的依赖

     <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

2.引入日志依赖 抽象层 与 实现层

        <!--引入日志依赖 抽象层 与 实现层-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.21</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.21</version>
        </dependency>

3. 配置：

log4j.rootLogger=DEBUG,stdout,file
log4j.additivity.org.apache=true

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.threshold=INFO
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%-5p %c{1}:%L - %m%n

log4j.appender.file=org.apache.log4j.DailyRollingFileAppender
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.DatePattern='.'yyyy-MM-dd-HH-mm
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
log4j.appender.file.Threshold=INFO
log4j.appender.file.append=true
log4j.appender.file.File=/workspaces/logs/foodie-api/imooc.log

4.编写测试类

package com.imooc.controller;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import springfox.documentation.annotations.ApiIgnore;

@ApiIgnore
//@Controller
@RestController
public class Hello {
    final static Logger logger = LoggerFactory.getLogger(Hello.class);
      @GetMapping("/hello111")
      public Object hello() {
          logger.debug("debug: hello~");
          logger.info("info: hello~");
          logger.warn("warn: hello~");
          logger.error("error: hello~");
          return "hello world1";
      }
}

效果：