上接：slf4j介绍
说明
slf4j不能单独使用，需要搭配日志框架，这里介绍 log4j
依赖方式
jar包依赖
- slf4j-api-xxx.jar
- slf4j-log4j12-xxx.jar
- log4j-1.2.17.jar
maven依赖
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.30</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.30</version>
</dependency>
log4j.properties
log4j.rootLogger=DEBUG, stdout ,file
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
log4j.appender.file = org.apache.log4j.FileAppender
log4j.appender.file.File = 1.log
log4j.appender.file.Encoding=UTF-8
#只将ERROR输出到文件中
#log4j.appender.file.Threshold=ERROR
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss}[ %p ]%m%n
log4j.appender.file.append = true
java代码
引包
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
创建log对象
static final Logger log= LoggerFactory.getLogger(当前类.class);
log对象打印日志
log.trace("trace级别:: {}",content);
log.debug("debug级别:: {}",content);
log.info("info级别:: {}",content);
log.warn("warn级别:: {}",content);
log.error("error级别:: {}",content);
java 完整代码
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Test {
static final Logger LOGGER= LoggerFactory.getLogger(Test.class);
public static void main(String[] args) {
for(int i=0;i<50;i++) {
LOGGER.debug("test debug");
LOGGER.info("test info");
LOGGER.warn("test warn");
LOGGER.error("test error");
}
}
}